#  How accurate are simulations and experiments for the lattice energies of
molecular crystals?

Flaviano Della Pia 1, Andrea Zen 2,3, Dario Alfè 2,3,4,5, and Angelos
Michaelides 1

1Yusuf Hamied Department of Chemistry, University of Cambridge, Cambridge CB2
1EW, United Kingdom
2 Dipartimento di Fisica Ettore Pancini, Università di Napoli Federico II,
Monte S. Angelo, I-80126 Napoli, Italy
3 Department of Earth Sciences, University College London, London WC1E 6BT,
United Kingdom
4 Thomas Young Centre, University College London, London WC1E 6BT, United
Kingdom
5 London Centre for Nanotechnology, University College London, London WC1E
6BT, United Kingdom

###### Abstract

Molecular crystals play a central role in a wide range of scientific fields,
including pharmaceuticals and organic semiconductor devices. However, they are
challenging systems to model accurately with computational approaches because
of a delicate interplay of intermolecular interactions such as hydrogen
bonding and van der Waals dispersion forces. Here, by exploiting recent
algorithmic developments, we report the first set of diffusion Monte Carlo
lattice energies for all 23 molecular crystals in the popular and widely used
X23 dataset. Comparisons with previous state-of-the-art lattice energy
predictions (on a subset of the dataset) and a careful analysis of
experimental sublimation enthalpies reveals that high-accuracy computational
methods are now at least as reliable as (computationally derived) experiments
for the lattice energies of molecular crystals. Overall, this work
demonstrates the feasibility of high-level explicitly correlated electronic
structure methods for broad benchmarking studies in complex condensed phase
systems, and signposts a route towards closer agreement between experiment and
simulation.

##  1 Introduction

Molecular crystals are of central importance to pharmaceuticals[1], organic
semiconductor devices[2, 3], optoelectronics [4], and medicine[5].
Computational approaches play a central role in molecular crystal research,
both in aiding experimental structure determination and in predicting their
stability. In particular, the computation of lattice energies is pivotal in
Crystal Structure Prediction, as often the relative stabilities of molecular
crystals are approximated using static lattice energies rather than finite
temperature free energy calculations[6, 7, 8].

The most widely used techniques for the calculation of molecular crystals are
empirical force-fields and density functional theory (DFT). These techniques
have been very successfully applied and have significantly advanced
understanding[9, 10, 11, 12, 13, 14, 6], particularly when modern force-field
parameterization and modern DFT exchange-correlation functionals are used.
However, despite the success, the accuracy of these methods is not always
clear and careful validation is required. Experiment and higher level
electronic structure theories are the two obvious sources of validation.
However, neither is entirely straightforward as direct like for like
comparison with experiment is challenging (see below) and high level
electronic structure references are scarce. Indeed, so far each computation of
a single lattice energy with a highly accurate correlated method represents a
tour de force study [15, 16, 17, 18, 19, 20, 17, 21], implying a lack of
extensive high-accuracy reference values for molecular crystals and periodic
solids in general.

Addressing this challenge, recent developments in electronic structure theory
enabled accurate and efficient calculations for both surfaces and condensed
phases[22, 23, 24, 18]. Among these, diffusion Monte Carlo (DMC) is very
promising for small and large molecules. DMC was shown[18] to deliver lattice
energies of molecular crystals at a computational cost comparable to the
Random-Phase-Approximation (RPA) but with the accuracy of the so-called "gold
standard" of quantum chemistry, coupled cluster with single, double, and
perturbative triple excitations [CCSD(T)]. Specifically, DMC has been
successfully applied to study 6 organic molecular crystals[18, 21] as well as
13 ice polymorphs[25], providing valuable insights into their energetics.

In this work, we consider the X23 dataset, the most used dataset for the
lattice energies of molecular crystals comprising 23 materials. Very recent
studies on X23 have shown that near chemical accuracy ($\sim 4\text{ kJ/mol}$)
can be achieved with second order Møller–Plesset perturbation theory (MP2)
calculations [26], and that coupled-cluster methods achieve sub-chemical
accuracy in the computation of the two-body terms[27]. Here, we provide DMC
reference computational values for the entire dataset. In addition, when
comparison with previous state-of-the-art calculations is possible, we show
that different high-accuracy computational methods agree on lattice energies
within $\sim 4\text{ kJ/mol}$, which is better than a sometimes larger
disagreement among experiments. The feasibility and accuracy of DMC for large
molecular crystals open up the road to lattice energies benchmarked directly
against computed high-accuracy computational values as well as the production
of reference values for more complex condensed phase systems.

##  2 Results and discussion

We start by elucidating the difference between lattice energy and sublimation
enthalpy, which is fundamental to the discussion presented throughout the
manuscript. In assessing the relative stability of molecular crystals,
simulations generally focus on computing the (zero temperature) lattice
energy, defined as:

$E_{\text{latt}}=E_{\text{crys}}-E_{\text{gas}},$ (1)

where $E_{\text{crys}}$ is the total energy per molecule in the crystal phase,
and $E_{\text{gas}}$ is the total energy of the isolated molecule in the gas
phase. However, the physical quantity measured in experiments is the
sublimation enthalpy. Experimental estimates of the lattice energy are then
obtained by subtracting from measured sublimation enthalpies a computational
vibrational term:

$E^{\text{exp}}_{\text{latt}}=-\Delta H_{\text{sub}}^{\text{exp}}(T)+\Delta
E^{\text{comp}}_{\text{vib}}(T),$ (2)

where $E^{\text{exp}}_{\text{latt}}$ is the experimental lattice energy,
$\Delta H_{\text{sub}}^{\text{exp}}$ is the measured sublimation enthalpy at
temperature $T$, and $\Delta E^{\text{comp}}_{\text{vib}}$ is the
computational vibrational term, comprising both zero-point energy and thermal
effects. It is important to mention here that $\Delta
E^{\text{comp}}_{\text{vib}}$ is challenging to obtain from computation: the
need for large periodic cells and the importance of anharmonicity in molecular
crystals means that this is in general not affordable with reference ab initio
methods[11].

Overall, this means that reference lattice energies were so far extrapolated
from experiments rather than computed with higher-level methods, which
introduces deviations as a result of comparing an experiment at finite
temperature to a simulated idealized model system. Moreover, our analysis on
the experimental sublimation enthalpy (see below) shows that deviations often
larger than the chemical accuracy limit characterize the measured value of
$\Delta H_{\text{sub}}^{\text{exp}}$. This introduces a (large) uncertainty on
$E^{\text{exp}}_{\text{latt}}$, which is independent of the (additional) error
on the vibrational computational contribution.

In the following, as illustrated schematically in Fig. 1, we show that
consensus within chemical accuracy is achieved on the lattice energy among
explicitly correlated electronic structure methods, in stark contrast to a
sometimes larger disagreement among experiments.

Figure 1: Schematic of the relation between the sublimation enthalpy $\Delta
H_{\text{sub}}$ and the lattice energy $E_{\text{latt}}$. Simulations directly
compute the lattice energy. Experimental estimates of the lattice energies
$E^{\text{exp}}_{\text{latt}}$ are obtained by subtracting a computational
vibrational contribution $\Delta E^{\text{comp}}_{\text{vib}}$ from
experimentally measured sublimation enthalpies $\Delta
H^{\text{exp}}_{\text{sub}}$. Lattice energies and sublimation enthalpies are
reported with red and blue bars, respectively. The left-hand-side illustrates
that different high-accuracy computational methods agree on the estimate of
the lattice energy within the chemical accuracy limit. This is opposed to the
experimental scenario (right-hand-side) which can be characterized by larger
uncertainties. The difference between the blue and red bars highlights that
the lattice energy is the largest contribution ($\sim 80\%$) to the
sublimation enthalpy.

### Consensus of computational methods on lattice energies

| (DMC) | (DMC+DFT) |
---|---|---|---
Crystal | Lattice energy | Sublimation enthalpy |
1,4-cyclohexanedione | -88.3 $\pm$ 1.0 | 79.4 |
Acetic acid | -71.7 $\pm$ 0.6 | 65.7 |
Adamantane | -61.0 $\pm$ 2.3 | 50.7 |
Ammonia | -38.2 $\pm$ 0.1 | 30.7 |
Anthracene | -100.2 $\pm$ 0.5 | 91.7 |
Benzene | -49.8 $\pm$ 0.2 | 39.9 |
CO2 | -29.4 $\pm$ 0.2 | 26.1 |
Cyanamide | -83.6 $\pm$ 0.4 | 77.6 |
Cytosine | -156.2 $\pm$ 1.0 | 149.0 |
Ethyl carbamate | -84.2 $\pm$ 1.3 | 74.7 |
Formamide | -81.0 $\pm$ 1.0 | 71.4 |
Imidazole | -88.2 $\pm$ 0.8 | 79.3 |
Naphthalene | -75.5 $\pm$ 0.5 | 66.7 |
Oxalic acid $\alpha$ | -102.6 $\pm$ 1.4 | 97.6 |
Oxalic acid $\beta$ | -102.3 $\pm$ 0.6 | 99.0 |
Pyrazine | -61.1 $\pm$ 1.1 | 53.2 |
Pyrazole | -77.3 $\pm$ 0.5 | 70.9 |
Triazine | -60.5 $\pm$ 0.6 | 53.6 |
Trioxane | -62.1 $\pm$ 1.9 | 53.7 |
Uracil | -134.3 $\pm$ 0.7 | 127.3 |
Urea | -108.5 $\pm$ 0.3 | 100.2 |
Hexamine | -86.2 $\pm$ 0.6 | 76.9 |
Succinic acid | -125.2 $\pm$ 0.5 | 118.2 |
Table 1: Lattice energies (kJ/mol) of the X23 molecular crystals computed with
DMC. The reported error is the DMC statistical error bar. As discussed in Sec.
2, the overall error due to approximations involved in DMC and the DFT
geometry optimization is estimated to be $\sim 2\text{ kJ/mol}$. The second
column reports the sublimation enthalpy (kJ/mol) at the temperature
$T_{\text{calc}}$, estimated as the sum of the DMC lattice energy computed in
this work and the DFT vibrational energies $\Delta
E^{\text{comp}}_{\text{vib}}(T_{\text{calc}})$ computed in Ref. [28]. The
temperature $T_{\text{calc}}$ is room temperature for every system except:
acetic acid ($T_{\text{calc}}=290\text{ K}$), ammonia
($T_{\text{calc}}=195\text{ K}$), benzene ($T_{\text{calc}}=279\text{ K}$),
carbon dioxide ($T_{\text{calc}}=207\text{ K}$) and formamide
($T_{\text{calc}}=276\text{ K}$). As discussed in Sec. 2, the overall error on
the sublimation enthalpy is estimated to be $\sim 6\text{ kJ/mol}$.

As described in equation 2, the experimental estimates of the lattice energy
are extrapolated via a computational vibrational term. For the X23 molecular
crystals, the term $\Delta E^{\text{comp}}_{\text{vib}}$ has been previously
computed with different approximations in Refs. [29, 30, 28]. The most recent
one, namely X23b[28], was obtained using the quasi-harmonic approximation,
averaging over four DFT functionals and taking into account both electronic
and vibrational energy due to thermal expansion, and is therefore used in this
work. In each of the previously reported datasets, a single initial value for
the sublimation enthalpy was chosen to obtain reference experimental lattice
energies. However, as discussed in Ref. [28], the uncertainty on the initial
value of the sublimation enthalpy can be larger than $\sim 5\text{ kJ/mol}$.
To conduct a careful comparison, we consider all the values of the sublimation
enthalpy $\Delta H_{\text{sub}}^{\text{exp}}$ reported in the literature
(except those highlighted as unreliable[31]), corrected with the X23b
vibrational energy. The values of $\Delta H_{\text{sub}}^{\text{exp}}$ as a
function of temperature were collected from Refs. [31, 32, 33, 34] and are
plotted in the Supporting Information (SI). The vibrational terms $\Delta
E^{\text{comp}}_{\text{vib}}$ were computed at a system specific temperature
$T_{\text{calc}}$ (listed in Table 1 caption and in the SI). The values of
$\Delta H^{\text{exp}}_{\text{sub}}\left(T_{\text{calc}}\right)$ at the
temperature $T_{\text{calc}}$ have been extrapolated according to the ideal
approximation as described in the SI (section 5.1).

The X23 lattice energies computed with DMC are reported in Table 1 and plotted
in Fig. 2. In the upper panel, we plot the DMC lattice energies for each
system, highlighting the variability of the X23 lattice energies over a
relatively large energy range going from $-160\text{ kJ/mol}$ to $-20\text{
kJ/mol}$. The bottom panel shows for each system the difference between the
experimental values (black dots) and the DMC lattice energies. The DMC
statistical error bars are reported in blue. We also report values previously
reported either with RPA with single corrections (RPA+GWSE) in Ref. [19] (red
squares) or with CCSD(T) methods (green triangles) in Refs. [20, 16],
available only for a few systems.

The range in which the experimentally derived lattice energies vary is often
larger than $\sim 4\text{ kJ/mol}$. In Fig. 2, this is evidenced by gold bars
- under which the number of available measurements is reported - highlighting
a current lack of consensus on the experimental value of the sublimation
enthalpy for several molecular crystals. On the other hand, high-accuracy
electronic structure methods generally agree within the chemical accuracy
limit. Noticeable are the cases of anthracene, benzene, naphthalene, and urea,
where computational methods agree within $\sim 4\text{ kJ/mol}$, as opposed to
the experimental uncertainties ranging from $\sim 10$ to $\sim 25\text{
kJ/mol}$.

Overall, the ‘distance’ between the experimental range (gold bar) and DMC is
always within $\sim 4\text{ kJ/mol}$ (with the only exception given by oxalic
acid $\beta$, where only one experimental measurement is available),
qualitatively validating the reliability of our estimates. Considering the
spread in the experimental values of the lattice energy and the additional
uncertainty on the necessary vibrational term (discussed below), we suggest
that directly computed high-accuracy computational lattice energies have
become at least as reliable as experimental ones, and could play a more
significant role in benchmarking empirical and ab initio methods.

Figure 2: Performance of computations and experiments on the X23 lattice
energies. (Top panel) DMC values of the electronic lattice energy for each
system (the dashed line is to guide the eye). DMC has predictive accuracy in a
large energy range going from $-160\text{ kJ/mol}$ to $-20\text{ kJ/mol}$.
(Bottom panel) Difference between experimentally derived lattice energy (black
dots) and DMC. The DMC statistical error bar is reported in blue. Experimental
lattice energies are obtained by correcting experimental sublimation
enthalpies with the most recent vibrational term (X23b), according to Eq. 2.
The gold bar highlights the range of existing experimental measurements. The
number of available experimental values is reported below each bar. Lattice
energies obtained with RPA+GWSE (red squares) and CCSD(T) based methods (green
triangles) are taken from Refs. [19, 20, 16].

### Comparable uncertainties in experiments and simulations on sublimation
enthalpies

So far we have focused on the performance of experiments and computation on
the lattice energy. However, experimental estimates of the lattice energy
involve the subtraction of a computational term. Therefore, we now address the
accuracy of experiments and state-of-the-art simulations for sublimation
enthalpies.

The experimental sublimation enthalpy, $\Delta
H_{\text{sub}}^{\text{exp}}(T)$, is directly measured in experiments.
Following the same procedure mentioned before and described in the SI, to
allow for comparison with simulations, we extrapolated $\Delta
H_{\text{sub}}^{\text{exp}}$ to the temperature $T_{\text{calc}}$ at which the
vibrational contribution was available[28].

We obtain the computational sublimation enthalpy, $\Delta
H_{\text{sub}}^{\text{comp}}$, as

$\Delta
H_{\text{sub}}^{\text{comp}}\left(T_{\text{calc}}\right)=-E_{\text{latt}}^{\text{DMC}}+\Delta
E_{\text{vib}}^{\text{DFT}}\left(T_{\text{calc}}\right),$ (3)

where $E^{\text{DMC}}_{\text{latt}}$ is the DMC lattice energy and $\Delta
E^{DFT}_{\text{vib}}$ is the DFT vibrational thermal contribution computed in
Ref. [28]. The values of $\Delta H_{\text{sub}}^{\text{comp}}$ are reported in
Table 1.

The errors on experimental sublimation enthalpy are due to: (1) the spread in
the reported measurement; and (2) the correction needed to extrapolate $\Delta
H_{\text{sub}}^{\text{exp}}$ to the target temperature. The range of variation
of the computational sublimation enthalpy is due to: (1) errors in the
computation of the lattice energy; and (2) errors in the computation of the
vibrational term. The uncertainty on the DMC lattice energy is due to methods
limitations (statistical error-bar, nodal surface, finite-size effect) and the
considered geometry, optimized at the DFT level. We estimate the total error
to be $\sim 2\text{ kJ/mol}$, as discussed in section 5.3 of the SI. Sources
of errors on the vibrational contribution are due to the inaccuracy of the DFT
potential energy surface (PES) and the considered approximations
(anharmonicity). Overall, an uncertainty of the order of $\sim 4\text{
kJ/mol}$ on $\Delta E_{\text{vib}}^{\text{DFT}}$ has to be taken into account
when comparing to experiments[29, 30, 28]. Finally, we get the total
uncertainty by adding the system specific error on $\Delta
E^{\text{DFT}}_{\text{vib}}$ reported in Ref. [28].

In Fig. 3 we plot the estimated range for the X23 sublimation enthalpies in
both experiments (gold) and computation (cyan). Different from the lattice
energy, it can be seen that state-of-the-art experimental and computational
uncertainties for molecular crystals sublimation enthalpies are comparable.
Moreover, they are overall larger than the sought after chemical accuracy
limit. This poses an interesting question on whether the criterion usually
considered to assess the quality of computational approaches is meaningful for
current methods. Overall, this work shows that to understand the accuracy of
high-level computational methods on sublimation enthalpies, we would need
both: (1) additional and accurate experimental measurements; and (2) to push
the application of high-accuracy methods to the computation of fully
anharmonic vibrational properties.

Figure 3: Comparison of uncertainties for experimental (gold) and state-of-
the-art computational (cyan) sublimation enthalpies. The gold bar is due to
the spread in the literature sublimation enthalpies, extrapolated to the
temperature $T_{\text{calc}}$ for which the computational vibrational
contribution is available[28]. The number of available experimental values is
reported below each bar. The cyan bar is due to geometry and methodological
approximations used in the computation of electronic lattice energies and
vibrational thermal contributions.

##  3 Conclusions

This work has focused on lattice energies of molecular crystals. This quantity
is not directly measured in experiments and corrections are needed for a
direct comparison to simulations. On the other hand, high-accuracy explicitly
correlated wave-functions methods were so far only applied to a few systems
due to the demanding computational cost. Building on recent developments that
enabled accurate and efficient diffusion Monte Carlo for large periodic unit
cells, we computed the lattice energies of the X23 molecular crystals with
DMC. The analysis of the performance of experiments and state-of-the-art
simulations shows that, where direct comparison is possible, different high-
accuracy computational methods have now reached consensus on the lattice
energies within chemical accuracy. Larger uncertainties characterize instead
experimental estimates. This work therefore provides valuable reference values
for 23 molecular crystals. More generally, recent studies showed consensus of
explicitly correlated methods for surface chemistry with chemical accuracy[35,
36, 24, 37]. Together with the advent of machine learning foundational models
for material chemistry[38, 39], potentially requiring minimal data to fine-
tune to a higher level of accuracy than the initial training, finite
temperature simulations with the accuracy of explicitly correlated methods
could soon become feasible. This overall highlights an exciting time for
future application of high-accuracy computational methods to both surfaces and
condensed phases of more complex systems. Finally, we have also shown that
uncertainties of experimental and state-of-the-art computational sublimation
enthalpies are currently comparable in magnitude. Our analysis suggests that
the overall accuracy of sublimation enthalpy estimates could benefit from
additional experiments as well as the application of higher-accuracy
techniques to vibrational properties.

##  4 Methods

Reference values for the lattice energies were computed with Fixed-Node DMC,
using the CASINO[40] code. We use energy-consistent correlated electron
pseudopotentials[41] (eCEPP) with the most recent determinant locality
approximation[42] (DLA). The trial wave functions were of the Slater-Jastrow
type with single Slater determinants, and the single-particle orbitals
obtained from DFT local-density approximation[43] (LDA) plane-wave
calculations performed with PWscf [44, 45] using an energy cut-off of
$600\text{ Ry}$ and re-expanded in terms of B-splines [46]. The Jastrow factor
included a two-body electron-electron (e-e) term, two-body electron-nucleus
(e-n) terms, and three-body electron-electron-nucleus (e-e-n) terms. The
variational parameters of the Jastrow have been optimized by minimizing the
variance in the simulated cell for each analyzed crystal. The size of the
simulation cell imposes some constraints on the Jastrow variational freedom,
in the form of cut-offs in the e-n, e-e, and e-e-n terms. Following the
workflow given in Ref. [18], tested on molecular crystals [18] and ice
polymorphs [25], the simulation cells have been generally defined in order to
guarantee the radius of the sphere inscribed in the Wigner-Seitz cell to be
bigger than $5\text{ \r{A}}$.

The time step $\tau$ is a key factor affecting the accuracy of DMC
calculations. In DMC, a propagation according to the imaginary time
Schrödinger equation is performed to project out the exact ground state from a
trial wave function [47]. A time step $\tau$ must be chosen, but the
projection is exact only in the continuous limit $\tau\to 0$. However, the
ZSGMA [48] DMC algorithm gives better convergence with respect to $\tau$ than
previously used methods because the time-step bias per molecule is independent
of the size of the simulated cell in molecular crystals [18]. In this work, we
have verified the time step convergence for each analyzed system, as reported
in the SI. We note that, in general, even in the limit of zero time step the
DMC energy may be biased by the choice of the Jastrow factor, depending on how
the non-local part of the pseudopotential is treated. This bias is eliminated
if the DLA scheme is employed.

The computation of $E_{\text{crys}}$ involves the use of periodic boundary
conditions that can be subject to significant finite size errors (FSE). We
took into account FSE using the Model Periodic Coulomb[49, 50, 51] (MPC)
correction, and further correct for the (smaller) Independent Particle FSE
(IPFSE) according to the procedure described in Ref. [18].

Further details on the DMC calculations, including the size of the supercell
used in the solid phase calculations, the total energy of the solid phase with
and without FSE corrections, and the total energy of the gas phase, are
reported in the SI.

The geometries of the molecular crystals were optimized at the DFT level with
the dispersion-inclusive functional optB88-vdW[52] using VASP[53, 54, 55, 56],
except for hexamine and succinic acid which were taken from Ref. [30]. The
k-point grid used for each system is reported in the SI. Tests on the effect
of the geometry optimization on the DMC lattice energy are reported in section
5.3 of the SI.

## Supporting Information

See the Supporting Information for: (1) the experimental sublimation
enthalpies reported in literature and extrapolated at the target temperature;
(2) the analysis on the error on the vibrational thermal contribution; (3)
details of the DMC calculations; (4) tests on the errors on the DMC lattice
energies; (5) the geometries used in this study for both condensed and gas
phases.

## Acknowledgements

Calculations were performed using the Cambridge Service for Data Driven
Discovery (CSD3) operated by the University of Cambridge Research Computing
Service (www.csd3.cam.ac.uk), provided by Dell EMC and Intel using Tier-2
funding from the Engineering and Physical Sciences Research Council (capital
grant EP/T022159/1 and EP/P020259/1), and DiRAC funding from the Science and
Technology Facilities Council (www.dirac.ac.uk). This work also used the
ARCHER UK National Supercomputing Service (https://www.archer2.ac.uk), the
United Kingdom Car Parrinello (UKCP) consortium (EP/ F036884/1). This research
used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge
National Laboratory, which is supported by the Office of Science of the U.S.
Department of Energy under Contract No. DE-AC05-00OR22725). AM acknowledges
support from the European Union under the “n-AQUA” European Research Council
project (Grant No. 101071937). D.A. and A.Z. acknowledges support from
Leverhulme grant no. RPG-2020-038, and from the European Union under the Next
generation EU (projects 20222FXZ33 and P2022MC742).

##  5 Supporting Information for ‘How accurate are simulations and experiments
for the lattice energies of molecular crystals?’

In the supporting information we provide:

  * •

the experimental sublimation enthalpies reported in literature and
extrapolated to the target temperature (called $T_{\text{calc}}$ in the main
manuscript) in section 5.1;

  * •

details of the DMC estimates of the lattice energy reported in the main
manuscript in section 5.2;

  * •

tests on the errors on the DMC lattice energies and on the time-step
convergence in sections 5.3 and 5.4;

  * •

the k-point grid used in the geometry optimization in section 5.5,

  * •

the geometry used in this study for each system in X23 in section 5.6.

###  5.1 Experimental sublimation enthalpies

In figure 4 we plot the literature values for the sublimation enthalpies of
each molecular crystal as a function of the temperature. Data are collected
from Refs. [31, 32, 33, 34, 29, 30, 28]. We explicitly report the plotted data
in table LABEL:tab:si-experimental-sublimation-enthalpies. The points are
color-coded according to the year of publication and the black dashed vertical
line highlights room temperature. Figure 4 shows that the spread in the
measured value is usually higher than $\sim 4\text{ kJ/mol}$. We notice that
cases where the experimental uncertainty shown in the main paper is small are
usually due to a lack of data (see, for instance, oxalic acid, pyrazole,
triazine).

Figure 4: Experimental sublimation enthalpies reported in the literature as a
function of the temperature. Points are color-coded according to the year of
publication.

The experimental lattice energies are obtained by subtracting the vibrational
energy computed in Ref. [28], according to the equation:

$E^{\text{exp}}_{\text{latt}}=-\Delta H^{\text{exp}}_{\text{sub}}(T)+\Delta
E^{\text{comp}}_{\text{vib}}(T).$ (4)

Since the vibrational energy is temperature dependent, we first need to
extrapolate the experimental value of the sublimation enthalpy to the
temperature $T_{\text{calc}}$ for which $\Delta E^{\text{comp}}_{\text{vib}}$
was computed[28]. The temperature $T_{\text{calc}}$ is room temperature for
every system except: acetic acid ($T_{\text{calc}}=290\text{ K}$), ammonia
($T_{\text{calc}}=195\text{ K}$), benzene ($T_{\text{calc}}=279\text{ K}$),
carbon dioxide ($T_{\text{calc}}=207\text{ K}$) and formamide
($T_{\text{calc}}=276\text{ K}$).

In figure 5 we plot the values of the sublimation enthalpy extrapolated at the
target temperature $T_{\text{calc}}$ using the ideal system approximation,
i.e.,

$\displaystyle\Delta H^{\text{exp}}_{\text{sub}}(T_{\text{calc}})=\Delta
H(T)-2R(T_{\text{calc}}-T)\hskip 56.9055pt\text{non linear molecules,}$ (5)
$\displaystyle\Delta H^{\text{exp}}_{\text{sub}}(T_{\text{calc}})=\Delta
H(T)-\frac{5}{2}R(T_{\text{calc}}-T)\hskip 56.9055pt\text{linear molecules.}$
(6)

Orange circles represent values experimentally measured at a temperature $T$
different from the temperature $T_{\text{calc}}$ (i.e., the values reported in
figure 4); cyan circles are the extrapolated values at temperature
$T_{\text{calc}}$. Original and extrapolated values are connected by an arrow.
We acknowledge that approaches more sophisticated than the ideal system
correction are possible (i.e., evaluating the vibrational contribution in the
quasi-harmonic approximation or use experimental heat capacity data). However,
the spread in the measured values is such that the error coming from the ideal
system approximation would be a minor correction to the analysis reported in
the main paper.

Figure 5: Experimental sublimation enthalpies extrapolated to the temperature
$T_{\text{calc}}$ according to equations 2 and 3. Orange circles are
experimentally measured values at temperature $T\neq T_{\text{calc}}$. Cyan
circles are the extrapolated values at temperature $T=T_{\text{calc}}$.
Original and extrapolated values are connected by an arrow.

Finally, in table LABEL:tab:si-experimental-sublimation-enthalpies we report
the summary of the experimental sublimation enthalpy measurements considered
in our analysis. The acronyms of the experimental techniques are defined in
Ref. [31] and reported in table 2 for clarity.

ME | Mass Effusion-Knudsen Effusion
---|---
TE | Torsion Effusion
A | calculated from the vapor pressure data reported by the method of least squares
TSGC | Temperature Scanning Gas Chromatography
BG | Bourdon Gauge
I | Isoteniscope
DBM | Dibutyl Pththalate Manometer
CGC-DSC | Combined Correlation Gas chromatography-Differential Scanning Calorimetry
H | Heat capacity
MEM | Modified Entrainment Method
GS | Gas Saturation, transpiration
HSA | Head Space Analysis
LE | Langmuir Evaporation
RG | Rodebush Gauge
DSC | Differential Scanning Calorimeter
MM | mercury manometer
GC | Gas Chromatography
QR | Quartz Resonator
DM | Diaphram manometer
KG | Knudsen Gauge
V | Viscosity gauge
E | Estimated value
QF | Quartz Fiber
MS | Mass Spectrometry
TPD | Temperature Programmed Desorption
TPTD | Temperature Programmed Thermal Expansion
n/a | not available

Table 2: Acronyms of the experimental methods defined in Ref. [31] and used in
table LABEL:tab:si-experimental-sublimation-enthalpies.

Table 3: Summary of experimental measurements of the sublimation enthalpy. For each system, the table reports respectively: the temperature at which the sublimation enthalpy is reported; the sublimation enthalpy (in kJ/mol, error reported in parentheses when available); the temperature range where the measurements was performed; the method used; the year of publication. The acronyms for the experimental methods are defined in Ref. [31] and reported in table 2. When the temperature is not explicitly stated in Ref. [31], we assume for its value the average of the temperature range. 1,4- Cyclohexanedione |  |  |  |
---|---|---|---|---
Temperature | Sublimation enthalpy | Temperature range | Method | Year
289 | 84.4 | n/a | C | 1980-1990
298 | 75(1) | n/a | TE | 1990-2000
298 | 84.2 | n/a | ME | 1980-1990
Acetic acid |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
223 | 67.3(1) | 213-230 | TE,ME | 1970-1980
213 | 70(1) | 213-230 | TE,ME | 1970-1980
Adamantane |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
308 | 58.3 | n/a | n/a | 2000-2010
293 | 59.7 | 278-368 | n/a | 1980-1990
343 | 55.3 | 328-373 | A | 1980-1990
358 | 54.3 | 343-483 | A | 1980-1990
300 | 59.5 | 278-443 | n/a | 1970-1980
326 | 59.7(0.8) | 310-336 | TSGC | 1970-1980
326 | 59.3(0.2) | 310-336 | BG | 1970-1980
332 | 53.6 | 312-366 | I | 1970-1980
333 | 58.6(0.6) | 313-353 | DBM | 1960-1970
298 | 59.0 | n/a | A | 2000-2010
298 | 53.0 | n/a | CGC-DSC | 1990-2000
298 | 58.0 | n/a | C | 1980-1990
298 | 59.6 | n/a | H | 1990-2000
298 | 60.5(1) | n/a | H | 1990-2000
298 | 54.8 | n/a | H | 1990-2000
298 | 59.3(0.2) | n/a | C | 1970-1980
298 | 59.5 | n/a | n/a | 1970-1980
298 | 60.5(1) | n/a | H | 1990-2000
298 | 62.3 | n/a | n/a | 1960-1970
Ammonia |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
186 | 31.2 | 177-195 | n/a | <1960
Anthracene |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
369 | 97.6(1) | 339-399 | ME | 2000-2010
337 | 97.9(0.6) | 320-355 | n/a | 2000-2010
340 | 98.4(0.7) | 320-350 | ME | 2000-2010
337 | 95.6(1) | 320-354 | n/a | 2000-2010
350 | 98.8(0.4) | 340-360 | ME | 2000-2010
358 | 102.5(2) | 348-368 | ME | 2000-2010
455 | 94.5 | 423-488 | MEM | 1990-2000
345 | 102.5 | 338-353 | ME | 1990-2000
341 | 100.0(3) | 318-363 | ME | 1990-2000
383 | 99.7 | 313-453 | GS | 1990-2000
346 | 98.7 | 318-373 | GS | 1980-1990
338 | 102.6 | 313-363 | GS | 1980-1990
376 | 94.3 | 353-399 | GS | 1980-1990
303 | 91.8(1) | 283-323 | GS | 1980-1990
338 | 91.2 | 323-353 | GS | 1980-1990
376 | 94.8 | 358-393 | GS | 1970-1980
405 | 98.8(0.4) | 363-448 | HSA | 1970-1980
350 | 97.2 | 328-372 | ME | 1970-1980
303 | 95.8(6) | 283-323 | LE | 1970-1980
392 | 101.0(0.5) | 353-432 | ME | 1970-1980
393 | 99.7 | n/a | C | 1970-1980
350 | 98.3(2) | 343-369 | n/a | 1970-1980
337 | 90.0(1) | 327-346 | TE | 1960-1970
338 | 103.4(3) | 303-373 | n/a | 1970-1980
408 | 97.5(2) | 396-421 | HSA | <1960
346 | 102.1 | 339-353 | n/a | <1960
345 | 102.1(2) | 338-353 | n/a | 1970-1980
364 | 92.0(2) | n/a | ME | <1960
353 | 90.4 | n/a | ME | <1960
353 | 93.3(4) | n/a | n/a | <1960
388 | 97.3(1) | 378-398 | RG | <1960
298 | 98.2 | 339-399 | ME | 1990-2000
298 | 100.2(0.4) | n/a | ME | 1990-2000
298 | 96.3(1) | n/a | DSC | 1990-2000
298 | 99.4 | n/a | CGC-DSC | 1980-1990
298 | 104.5(2) | n/a | TE,ME | 1980-1990
298 | 102.9(5) | n/a | TE | 1970-1980
Benzene |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
265 | 41.7 | 258-273 | n/a | 1990-2000
264 | 45.2 | 223-279 | A | 1980-1990
278 | 45.1 | n/a | n/a | 1980-1990
193 | 53.9(0.8) | n/a | n/a | 1970-1980
193 | 49.4(0.4) | n/a | n/a | 1970-1980
279 | 45.6 | 221-268 | MM | 1970-1980
261 | 44.1 | n/a | n/a | 1960-1970
229 | 43.1 | n/a | n/a | 1960-1970
279 | 44.6 | n/a | n/a | <1960
282 | 46.6 | 263-270 | A | <1960
273 | 44.6 | n/a | n/a | 1970-1980
226 | 43.4 | 214-238 | A | <1960
298 | 44.4 | 183-197 | TE,ME | 1980-1990
CO2 |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
207 | 26.1 | 198-216 | A | 1980-1990
86 | 27.2(0.4) | 70-102 | LE | 1970-1980
188 | 25.9 | 179-198 | n/a | <1960
167 | 26.3 | 129-195 | A | <1960
195 | 25.2 | 154-196 | n/a | <1960
Cyanamide |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
290 | 75.9 | 227-289 | TE,ME | 1980-1990
298 | 75.2 | n/a | n/a | 1980-1990
Cytosine |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
365 | 167.7(0.5) | 320-410 | QR,ME | 2000-2010
515 | 151.7(0.7) | 505-525 | GS | 1990-2000
453 | 147.2(3) | 423-483 | ME | 1980-1990
298 | 155.0(3) | n/a | n/a | 1980-1990
298 | 167.0(10) | n/a | TE | 1980-1990
298 | 176.0(10) | 450-470 | C | 1980-1990
Ethyl carbamate |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
265 | 77.7 | 256-273 | TE,ME | 1980-1990
322 | 71.9 | n/a | n/a | 1970-1980
299 | 89.1(0.8) | 292-307 | GS | <1960
298 | 76.0 | n/a | n/a | 1980-1990
Formamide |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
264 | 72.4 | 251-273 | TE,ME | 1980-1990
276 | 71.7 | n/a | n/a | 1970-1980
298 | 71.7 | n/a | n/a | 1980-1990
Imidazole |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
300 | 83.1(0.2) | 292-309 | ME | 1980-1990
301 | 80.8 | 288-310 | TE,ME | 1980-1990
298 | 83.1(0.2) | n/a | ME | 1980-1990
298 | 74.5(0.5) | n/a | C | 1980-1990
298 | 85.3 | n/a | n/a | 1960-1970
Naphthalene |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
285 | 88.0(2.5) | 267-303 | ME | 1990-2000
333 | 71.7 | 313-353 | GS | 1990-2000
258 | 73.7(1) | 243-273 | GS | 1990-2000
344 | 78.2(1) | 337-352 | GC | 1980-1990
323 | 70.9(0.4) | n/a | DSC | 1980-1990
315 | 73.4 | 299-331 | GS | 1980-1990
363 | 69.9 | 333-393 | GS | 1980-1990
312 | 72.3(1) | 293-331 | QR | 1980-1990
303 | 75.8(1) | 283-323 | GS | 1980-1990
327 | 72.8 | 302-352 | GS | 1980-1990
278 | 72.8(0.3) | 271-285 | ME | 1980-1990
313 | 72.5(0.1) | 274-353 | DM | 1980-1990
363 | 76.0(2) | 328-398 | DSC | 1980-1990
263 | 72.6(0.6) | 253-273 | TE | 1980-1990
293 | 71.3 | 280-305 | GS | 1970-1980
263 | 74.8(0.4) | 253-273 | TE | 1970-1980
263 | 73.9(0.2) | 253-273 | ME | 1970-1980
316 | 74.3(2) | 303-329 | TSGC | 1970-1980
303 | 72.5(0.3) | 263-343 | DM | 1970-1980
280 | 67.8(3.5) | n/a | HSA | 1970-1980
285 | 64.0(5) | 281-290 | LE | 1970-1980
303 | 72.7 | 283-323 | ME | 1970-1980
245 | 72.7(0.3) | 230-260 | KG | 1960-1970
280 | 66.3 | 276-283 | V | <1960
293 | 65.8 | 283-303 | Effusion | <1960
268 | 69.2 | 253-283 | n/a | <1960
292 | 72.1 | 273-311 | n/a | <1960
286 | 72.4 | 279-294 | n/a | <1960
298 | 70.4 | n/a | CGC-DSC | 1990-2000
298 | 72.3(0.4) | n/a | DSC | 1980-1990
298 | 72.6(0.1) | n/a | TE,ME,DM | 1980-1990
298 | 72.4(1) | n/a | C | 1980-1990
298 | 72.5 | n/a | GS | 1970-1980
298 | 72.1(0.25) | n/a | C | 1970-1980
298 | 73.0(0.3) | n/a | C | 1970-1980
298 | 64.0 | n/a | ME | <1960
298 | 66.5(2) | n/a | QF | <1960
Oxalic acid alpha |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
316 | 93.4 | 303-328 | n/a | 1980-1990
298 | 93.7(1) | n/a | TE | 1970-1980
Oxalic acid beta |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
318 | 93.3 | 310-325 | n/a | 1980-1990
Pyrazine |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
303 | 56.2 | 288-317 | n/a | 1990-2000
Pyrazole |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
275 | 74.3(0.4) | 268-287 | ME | 1980-1990
265 | 72.7 | 253-273 | TE,ME | 1980-1990
298 | 74.0(0.4) | n/a | n/a | 1980-1990
298 | 69.2(0.3) | n/a | C | 1980-1990
Triazine |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
222 | 58.2 | 212-229 | TE,ME | 1980-1990
298 | 54.2(0.2) | n/a | n/a | 1980-1990
Trioxane |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
223 | 57.9 | 212-231 | TE,ME | 1980-1990
298 | 55.6 | n/a | n/a | 1980-1990
298 | 56.5 | n/a | C | 1970-1980
298 | 56.2(0.2) | n/a | C | 1970-1980
Uracil |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
425 | 125.3(0.2) | 315-435 | QR,ME | 2000-2010
405 | 130.8 | 399-411 | ME | 2000-2010
439 | 127.0(2) | 394-494 | TE | 2000-2010
519 | 130.6(4) | 452-587 | TE,ME | 1980-1990
403 | 120.5(1) | 378-428 | QR | 1980-1990
425 | 121.7 | n/a | MS | 1970-1980
523 | 133.9(8) | 500-545 | HSA | 1970-1980
440 | 126.5(2) | n/a | C | 1970-1980
426 | 120.5(5) | 393-458 | LE | 1970-1980
298 | 131.0(5) | 452-587 | TE,GS | 1970-1980
Urea |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
370 | 94.6(2) | 329-403 | ME | 2000-2010
350 | 95.1(2) | 329-403 | ME | 2000-2010
350 | 94.6(0.5) | n/a | C | 2000-2010
381 | 90.9 | n/a | n/a | 1980-1990
357 | 87.7 | 345-368 | n/a | 1980-1990
351 | 96.9 | 338-362 | TE,ME | 1980-1990
361 | 95.4 | n/a | n/a | 1970-1980
356 | 87.9(2) | 345-368 | n/a | 1970-1980
357 | 88.2 | n/a | n/a | 1980-1990
298 | 95.5(0.3) | 358-402 | GS | 2000-2010
298 | 98.6 | n/a | n/a | 1980-1990
Hexamine |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
359 | 77.7 | 338-378 | GS | 2000-2010
313 | 76.8 | 298-453 | A | 1980-1990
316 | 78.8 | 302-328 | TE,ME | 1980-1990
289 | 74.1 | 281-298 | TE | <1960
298 | 80.0 | n/a | GS | 2000-2010
298 | 75.0(3) | n/a | V | 1970-1980
298 | 75.0(3) | n/a | n/a | <1960
Succinic acid |  |  |  |
Temperature | Sublimation enthalpy | Temperature range | Method | Year
338 | 128.0(2) | 318-358 | TPD | 2000-2010
291 | 119.5 | 280-302 | TPTD | 2000-2010
368 | 120.5 | 356-376 | TE,ME | 1980-1990
386 | 118.1(3) | 372-401 | ME | 1970-1980
298 | 123.0(3) | n/a | n/a | 2000-2010
298 | 122.0(3) | n/a | n/a | 1990-2000
298 | 120.0(4) | n/a | n/a | 1970-1980

###  5.2 Details of the DMC estimates of the lattice energy

In table 4 we report further details on the estimates of the X23 lattice
energies with DMC. In particular, we report for each system: (1) the size of
the supercell used in the DMC calculation; (2) the number of electrons per
molecule, $N_{\text{e}}$; (3) the number of molecules in the unit cell,
$N_{\text{mol}}$; (4) the total energy of the solid with the Ewald summation;
(5) the total energy of the solid with the Model Periodic Coulomb (MPC)
correction; (5) the Independent Particle Finite Size Error (IPFSE); and (5)
the total energy of the gas phase.

Crystal | Cell | $N_{\text{e}}$ | $N_{\text{mol}}$ | Ewald (eV/unit cell) | MPC (eV/unit cell) | IPFSE (eV/unit cell) | Gas phase (eV/atom)
---|---|---|---|---|---|---|---
1,4-cyclohexanedione | 2x2x2 | 44 | 2 | -3858.690 (0.019) | -3858.184 (0.020) | 0.0041 | -1928.179 (0.002)
Acetic acid | 1x3x2 | 24 | 4 | -4986.300 (0.022) | -4985.664 (0.023) | 0.0013 | -1245.673 (0.002)
Adamantane | 2x2x2 | 56 | 2 | -3616.719 (0.046) | -3616.198 (0.048) | 0.0197 | -1807.476 (0.002)
Ammonia | 2x2x2 | 8 | 4 | -1279.108 (0.002) | -1278.718 (0.002) | 0.0057 | -319.285 (0.001)
Anthracene | 1x2x1 | 66 | 2 | -4655.195 (0.010) | -4652.944 (0.009) | -0.0418 | -2325.454 (0.003)
Benzene | 2x2x2 | 30 | 4 | -4100.258 (0.008) | -4099.797 (0.008) | 0.0002 | -1024.433 (0.001)
CO2 | 2x2x2 | 16 | 4 | -4105.625 (0.009) | -4105.159 (0.009) | 0.0003 | -1025.986 (0.001)
Cyanamide | 2x2x2 | 16 | 8 | -5818.815 (0.037) | -5818.347 (0.032) | 0.0012 | -726.427 (0.001)
Cytosine | 1x1x3 | 42 | 4 | -7789.765 (0.039) | -7788.162 (0.041) | 0.0315 | -1945.429 (0.002)
Ethyl carbamate | 2x2x2 | 36 | 2 | -3441.354 (0.026) | -3440.894 (0.026) | 0.0120 | -1719.580 (0.002)
Formamide | 3x2x2 | 18 | 4 | -3640.269 (0.038) | -3639.963 (0.039) | 0.0020 | -909.152 (0.001)
Imidazole | 2x2x2 | 26 | 4 | -4277.264 (0.035) | -4276.749 (0.033) | 0.0035 | -1068.274 (0.002)
Naphthalene | 2x2x2 | 48 | 2 | -3352.167 (0.010) | -3351.621 (0.010) | 0.0066 | -1675.031 (0.003)
Oxalic acid alpha | 2x2x2 | 34 | 4 | -8339.690 (0.054) | -8339.118 (0.056) | 0.0004 | -2083.716 (0.002)
Oxalic acid beta | 2x2x3 | 34 | 2 | -4169.899 (0.011) | -4169.514 (0.011) | 0.0273 | -2083.711 (0.002)
Pyrazine | 2x2x3 | 30 | 2 | -2445.925 (0.023) | -2445.602 (0.023) | -0.0025 | -1222.167 (0.001)
Pyrazole | 2x1x2 | 26 | 8 | -8549.553 (0.042) | -8548.540 (0.043) | 0.0004 | -1067.766 (0.002)
Triazine | 1x2x2 | 30 | 6 | -7933.725 (0.072) | -7932.856 (0.034) | 0.0354 | -1321.522 (0.002)
Trioxane | 1x2x2 | 36 | 6 | -11205.590 (0.111) | -11204.542 (0.117) | 0.0165 | -1866.782 (0.002)
Uracil | 1x1x3 | 42 | 4 | -8386.464 (0.028) | -8384.954 (0.028) | 0.0211 | -2094.852 (0.002)
Urea | 2x2x2 | 24 | 2 | -2395.398 (0.005) | -2394.889 (0.006) | 0.0383 | -1196.339 (0.001)
Hexamine | 2x2x2 | 56 | 1 | -2203.616 (0.006) | -2203.079 (0.006) | -0.0071 | -2202.178 (0.003)
Succnic acid | 2x1x2 | 46 | 2 | -4921.200 (0.008) | -4920.115 (0.009) | -0.0017 | -2458.760 (0.002)

Table 4: Details of the DMC calculations of the lattice energies. The table
reports respectively: name of the system; cell used in the DMC simulations;
number of electrons $N_{\text{e}}$ per molecule; number of molecules
$N_{\text{mol}}$ in the unit cell; Ewald energy; MPC energy; IPFSE; energy in
the gas phase. The energies of the solid phases are in eV/unit cell. The
statistical DMC error bar on each energy is reported in parentheses. All the
energies are computed with a time step of $0.01\text{ au}$.

###  5.3 Error on the DMC lattice energies

As discussed in the main paper, the main source of errors on the DMC estimates
of the lattice energies are: (1) the considered geometry (because it is
optimized at the DFT level); and (2) the pseudopotentials. We tested these
errors on two showcase systems and estimate the total DMC error to be $\sim
1-2\text{ kJ/mol}$. We report the error analysis in figure 6 as follows. In
panels a and b we compute the DMC lattice energy of urea and cytosine
considering geometries optimized with different DFT functionals. We estimate
the error due to the DFT geometry optimization to be $\sim 1-2\text{ kJ/mol}$.
In panel c we report the DMC lattice energy of urea with two different
pseudopotentials, namely eCEPP[41] (used in this work) and the Dirac-Fock [57,
58] used in a previous work [18]. The DMC estimates (converged with respect to
the time step) are consistent within the statistical error bar.

Figure 6: Panels (a,b): DMC lattice energy of urea (a) and cytosine (b) as a
function of the time step for geometries optimized with different DFT
functionals. (c) Test on the dependence of the DMC lattice energy of cytosine
on the pseudopotentials: the results obtained with two different
pseudopotentials, eCEPP and Dirac-Fock, agree within the DMC statistical error
bar.

###  5.4 Time step convergence of the DMC lattice energies

The time step convergence is a key factor affecting the DMC estimates of the
lattice energy, as discussed in the methodological section of the main paper.
In figure 7, we report the DMC lattice energy as a function of the simulation
time step for each molecular crystal. The DMC values reported in the main
manuscript are computed with a time step of $0.01\text{ au}$.

Figure 7: Convergence of the DMC estimates of the lattice energies with
respect to the simulation time step. For each system, we plot the DMC lattice
energy (in kJ/mol) as a function of the time step (in atomic units). The DMC
values reported in the main manuscript are computed with a time step of
$0.01\text{ au}$.

###  5.5 DFT geometry optimization: k-point grid

Table 5 reports the k-point grid used in the geometry optimization of the C21
molecular crystals. The geometries of hexamine and succinic acid were instead
taken from Ref. [30].

Crystal | k-point
---|---
1,4-cyclohexanedione | 4 $\times$ 4 $\times$ 4
Acetic acid | 2 $\times$ 6 $\times$4
Adamantane | 4 $\times$4 $\times$3
Ammonia | 5$\times$ 5$\times$ 5
Anthracene | 3 $\times$4$\times$ 3
Benzene | 3$\times$ 3 $\times$4
CO2 | 4 $\times$4$\times$ 4
Cyanamide | 4 $\times$4$\times$ 3
Cytosine | 2 $\times$3 $\times$6
Ethyl carbamate | 5$\times$ 4 $\times$4
Formamide | 7 $\times$3$\times$ 4
Imidazole | 3 $\times$5$\times$ 3
Naphthalene | 3 $\times$4 $\times$4
Oxalic acid $\alpha$ | 4 $\times$3 $\times$4
Oxalic acid $\beta$ | 5 $\times$4$\times$ 5
Pyrazine | 3 $\times$4 $\times$6
Pyrazole | 3 $\times$2$\times$ 4
Trazine | 3 $\times$3 $\times$4
Trioxane | 3 $\times$3 $\times$3
Uracil | 2 $\times$2$\times$ 8
Urea | 4$\times$ 4 $\times$5
Table 5: K-point grid used in the DFT geometry optimization of the C21
molecular crystals.

###  5.6 Geometries input file

In this section we report the geometries used in this study for the solid and
gas phase of each system in X23.

#1,4-cyclohexanedione solid
32
Lattice="6.65 0.0 0.0 0.0 6.21 0.0 -1.1717 0.0 6.76934"
C 2.33943089 1.04586116 3.02756362
C 3.13887313 4.15083595 3.74173847
C 3.14137928 1.05381535 1.74135694
C 2.33691542 4.15883532 5.02795636
C 2.29867793 1.33346282 0.48877110
C 3.17959951 4.43849035 6.28055129
C 1.08332498 0.43536293 0.40805506
C 4.39495512 3.54038448 6.36128494
C 0.37649894 0.15086096 1.71907703
C 5.10180566 3.25587766 5.05026518
C 0.83730031 1.05013608 2.87842371
C 4.64100946 4.15512845 3.89089757
H 3.96089164 1.78027943 1.83683828
H 1.51740513 4.88529816 4.93245801
H 3.60389202 0.05582253 1.67214589
H 1.87438580 3.16085041 5.09717249
H 1.90932203 2.36598386 0.54620435
H 3.56892295 5.47102280 6.22313664
H 1.71476999 1.23496380 6.33619097
H 3.76351179 4.33995724 0.43312965
H 0.57544710 5.30210115 1.95712011
H 4.90286638 2.19711347 4.81225456
H 5.94594506 0.24488577 1.55324000
H -0.46764658 3.34991784 5.21610880
H 0.55431857 2.09483363 2.65179757
H 4.92397862 5.19982866 4.11753328
H 0.37110885 0.76904526 3.83221532
H 5.10722007 3.87403276 2.93710016
O 2.89744551 1.02711290 4.12245462
O 2.58085944 4.13202363 2.64683262
O -0.47541052 6.15417747 6.12126120
O 5.95364385 3.04915853 0.64807731
#1,4-cyclohexanedione molecule
16
Lattice="19.0 0.0 0.0 0.0 19.0 0.0 0.0 0.0 19.0"
C 8.88549500 8.18627000 9.31883000
C 10.38056500 8.38655000 9.03672000
C 9.95913500 10.72654000 10.02168000
C 8.78468500 10.74207000 9.03431000
C 10.95393500 9.60975000 9.73853000
C 8.04929500 9.41075000 8.97339000
H 10.97825500 7.51183000 9.31492000
H 10.53646500 8.53934000 7.95552000
H 8.73398500 7.99364000 10.39427000
H 9.58108500 10.56042000 11.04448000
H 10.49919500 11.67930000 10.04260000
H 9.15869500 10.94424000 8.01650000
H 8.06013500 11.53179000 9.26022000
H 8.47349500 7.32070000 8.78900000
O 12.12625500 9.68930000 10.05298000
O 6.87374500 9.33069000 8.67122000
————————————————–
#Acetic acid solid
32
Lattice="13.151 0.0 0.0 0.0 3.923 0.0 0.0 0.0 5.762"
C 4.40741914 2.74913621 1.21164337
C 8.74357321 1.17389375 4.09262644
C 10.98296382 3.13530616 1.21169907
C 2.16803416 0.78771224 4.09271522
C 5.39825986 2.42504225 2.28754074
C 7.75273569 1.49797023 5.16853109
C 11.97382209 3.45942900 2.28757823
C 1.17717269 0.46357601 5.16858919
H 4.19452344 3.72797287 5.30862135
H 8.95647340 0.19506169 2.42760164
H 10.77006915 2.15646549 5.30867882
H 2.38092565 1.76656395 2.42769936
H 4.91284832 1.87478714 3.09684732
H 8.23814574 2.04822169 0.21584139
H 11.48840010 0.08669600 3.09686908
H 1.66259297 3.83630400 0.21587789
H 6.20651838 1.81612928 1.85997857
H 6.94446882 2.10688253 4.74098133
H 12.78205678 0.14535254 1.85999429
H 0.36894322 3.77765588 4.74099344
H 5.85762740 3.34640838 2.66509913
H 7.29337796 0.57659672 5.54608280
H 12.43318067 2.53807833 2.66514894
H 0.71780489 1.38492438 5.54615861
O 4.90922284 3.49806769 0.23572895
O 8.24177516 0.42495788 3.11671120
O 11.48474579 2.38629810 0.23582311
O 1.66624824 1.53671580 3.11683815
O 3.23161621 2.36369990 1.19313692
O 9.91937265 1.55934591 4.07411440
O 9.80718018 3.52079449 1.19315582
O 3.34381995 0.40223756 4.07417882
#Acetic acid molecule
8
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 9.70683000 11.13026000 11.00030000
C 11.20960000 11.11776000 11.00128000
O 11.93428000 12.08798000 11.00089000
O 11.69701000 9.83950000 11.00357000
H 9.35016000 12.16050000 11.00002000
H 9.32984000 10.60096000 10.11785000
H 9.32921000 10.60076000 11.88215000
H 12.67079000 9.91916000 11.00080000
————————————————–
#Adamantane solid
52
Lattice="6.639 0.0 0.0 0.0 6.639 0.0 0.0 0.0 8.918"
C 6.58155455 6.58155701 1.77900740
C 6.41734506 1.19108982 0.89108350
C 1.02232719 1.35546855 8.91359096
C 0.10676434 5.33302432 0.89108306
C 5.16864494 1.02233000 0.00440917
C 1.19108652 0.10676835 8.02691752
C 5.50178203 5.16864547 8.91359094
C 1.35546421 5.50178415 0.00440904
C 5.33302277 6.41734608 8.02691754
C 6.58155411 6.58155710 7.13899232
C 3.26205485 3.26205737 2.67999144
C 3.26205510 3.26205712 6.23800612
C 3.42626403 4.51058999 3.56791565
C 4.51058677 3.09784590 5.35008113
C 3.09784543 2.01352437 3.56791523
C 2.01352303 3.42626818 5.35008134
C 2.18228182 4.67496862 4.46340822
C 4.67496442 4.34182982 4.45458981
C 4.34182770 1.84914562 4.46340781
C 1.84914523 2.18228448 4.45458944
H 0.82123061 0.05744290 2.43499833
H 6.30172863 2.08544737 1.52708636
H 1.92070069 1.50152990 0.61686072
H 0.91664809 2.25503076 8.28349222
H 5.70287867 6.46667122 2.43499834
H 0.22238051 4.43866674 1.52708624
H 5.02258571 1.92069984 8.30113287
H 4.26908091 0.91665330 0.63450513
H 2.08544653 0.22238246 7.39091822
H 4.60340841 5.02258419 0.61686058
H 5.60746114 4.26908328 8.28349203
H 1.50152343 4.60341419 8.30113275
H 2.25502822 5.60746074 0.63450508
H 4.43866268 6.30173163 7.39091814
H 6.46666367 0.82123094 6.48299920
H 0.05744545 5.70288373 6.48299911
H 2.38337863 3.37694333 2.02400079
H 3.37694538 4.14073051 6.89399969
H 4.14073079 3.14717153 2.02400075
H 3.14716401 2.38338357 6.89399980
H 3.54188065 5.40494761 2.93191255
H 5.40494655 2.98223188 5.98608044
H 2.98222893 1.11916692 2.93191212
H 1.11916279 3.54188211 5.98608044
H 1.28390869 4.82102984 3.84213813
H 4.82102342 5.24020017 5.07586612
H 5.24020092 1.70308456 3.84213796
H 1.70308602 1.28391414 5.07586565
H 2.28796110 5.57453062 5.09350675
H 5.57452852 4.23615372 3.82449360
H 4.23614839 0.94958366 5.09350634
H 0.94958103 2.28796079 3.82449334
#Adamantane molecule
26
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 11.00033000 11.00006000 9.22329000
C 10.99981000 10.99999000 12.77707000
C 11.16530000 12.24794000 10.10991000
C 9.75197000 11.16532000 11.89040000
C 10.83484000 9.75212000 10.10977000
C 12.24780000 10.83463000 11.89061000
C 9.92053000 12.41087000 11.00134000
C 9.58918000 9.92069000 10.99865000
C 12.07938000 9.58908000 11.00150000
C 12.41075000 12.07938000 10.99913000
H 10.12250000 11.11569000 8.56868000
H 10.88401000 10.12194000 13.43126000
H 11.87861000 10.88437000 8.56922000
H 11.11564000 11.87808000 13.43132000
H 11.28308000 13.13899000 9.47466000
H 8.86077000 11.28300000 12.52556000
H 10.71699000 8.86110000 9.47442000
H 13.13892000 10.71682000 12.52582000
H 9.02510000 12.55174000 10.37645000
H 9.44800000 9.02511000 11.62331000
H 12.97502000 9.44796000 10.37686000
H 12.55165000 12.97493000 11.62391000
H 10.02212000 13.31003000 11.62874000
H 8.69013000 10.02241000 10.37117000
H 11.97774000 8.68997000 11.62893000
H 13.30987000 11.97806000 10.37165000
————————————————–
#Ammonia solid
16
Lattice="5.1305 0.0 0.0 0.0 5.1305 0.0 0.0 0.0 5.1305"
N 1.04470891 1.04467975 1.04472578
N 3.60995847 1.52057361 4.08577516
N 4.08580811 3.60992798 1.52051951
N 1.52055891 4.08582692 3.60997900
H 1.86198440 1.39631721 0.53263233
H 1.39638414 0.53260446 1.86208330
H 0.53256637 1.86191453 1.39633557
H 4.42723342 1.16893701 4.59786767
H 3.96163521 2.03264968 3.26841562
H 3.09781668 0.70333959 3.73416376
H 3.73412397 3.09785652 0.70317001
H 4.59793363 4.42716029 1.16892118
H 2.03268616 3.26859071 3.96157834
H 0.70326905 3.73418703 3.09787790
H 1.16887653 4.59789554 4.42732765
H 3.26851588 3.96156632 2.03262046
#Ammonia molecule
4
Lattice="20.0 0.0 0.0 0.0 20.0 0.0 0.0 0.0 20.0"
N 9.82043500 9.82050500 9.82051000
H 10.66326500 10.12949500 9.33673000
H 10.12951500 9.33672500 10.66327000
H 9.33673500 10.66327500 10.12951000
————————————————–
#Anthracene solid
48
Lattice="8.4144 0.0 0.0 0.0 5.9903 0.0 -6.4104 0.0 9.05607"
C -1.64278629 0.15473549 3.34291581
C -0.82774836 0.93576416 2.55997539
C -0.40533504 0.49190276 1.27088277
C 0.41565004 1.27145567 0.44481548
C 7.58120584 5.17873552 0.81242098
C 6.73745618 4.39918051 1.65680431
C 6.33623125 4.86911648 2.88318636
C -5.57720583 0.81156448 8.24364899
C 1.58834997 4.71884433 8.61125450
C 2.40933505 5.49839724 7.78518721
C -4.73345617 1.59111950 7.39926567
C 2.83174837 5.05453585 6.49609459
C -4.33223124 1.12118352 6.17288362
C 3.64678630 5.83556451 5.71315417
C -0.56041402 3.14988618 5.71315393
C 2.56441402 2.84041385 3.34291606
C -1.37545161 3.93091483 6.49609473
C 3.37945162 2.05938520 2.55997526
C -1.79786502 3.48705332 7.78518757
C 3.80186503 2.50324672 1.27088242
C -2.61884992 4.26660587 8.61125510
C 4.62284993 1.72369417 0.44481490
C -1.37000589 2.18358588 8.24364882
C 3.37400590 3.80671415 0.81242118
C -0.52625663 1.40403077 7.39926513
C 2.53025663 4.58626926 1.65680486
C -0.12503183 1.87396707 6.17288300
C 2.12903183 4.11633295 2.88318700
H -1.95525169 0.51408641 4.32354488
H -0.49437099 1.91459330 2.90572735
H 0.74568187 2.25281061 0.79155651
H 6.41437812 3.41943849 1.30782470
H 5.68509061 4.25802909 3.51036065
H 1.25831814 3.73748940 8.26451346
H -4.41037811 2.57086151 7.74824528
H 2.49837100 4.07570670 6.15034263
H -3.68109059 1.73227091 5.54570933
H 3.95925171 5.47621359 4.73252511
H -0.24794889 3.50923732 4.73252491
H 2.25194889 2.48106270 4.32354508
H -1.70882924 4.90974402 6.15034314
H 3.71282925 1.08055601 2.90572686
H -2.94888200 5.24796087 8.26451427
H 4.95288201 0.74233917 0.79155573
H -0.20317849 0.42428874 7.74824482
H 2.20717849 5.56601129 1.30782518
H 0.52610877 1.26287955 5.54570871
H 1.47789123 4.72742047 3.51036129
#Anthracene molecule
24
Lattice="25.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 20.0"
C 9.70814500 8.53389500 9.99697000
C 11.07889500 8.53406500 10.00191000
C 11.81211500 9.75713500 10.00117000
C 11.07957500 11.00333500 9.99515000
C 9.65442500 10.95759500 9.99026000
C 8.98762500 9.75985500 9.99104000
C 13.21132500 9.78972500 10.00587000
C 11.78851500 12.21014500 9.99437000
C 13.18784500 12.24273500 9.99904000
C 13.92026500 10.99656500 10.00492000
C 15.34546500 11.04238500 10.00967000
C 16.01246500 12.24008500 10.00877000
C 15.29176500 13.46595500 10.00303000
C 13.92096500 13.46576500 9.99820000
H 15.89636500 10.10276500 10.01423000
H 13.76386500 8.84969500 10.01026000
H 9.16195500 7.59306500 9.99738000
H 11.63208500 7.59581500 10.00630000
H 9.10357500 11.89719500 9.98577000
H 7.89983500 9.74040500 9.98735000
H 11.23587500 13.15021500 9.98997000
H 17.10016500 12.25958500 10.01261000
H 15.83786500 14.40693500 10.00258000
H 13.36776500 14.40398500 9.99404000
————————————————–
#Benzene solid
48
Lattice="7.39 0.0 0.0 0.0 9.42 0.0 0.0 0.0 6.81"
C 6.94634688 1.32481685 6.76645828
C 6.37040201 0.42621627 0.85894469
C 0.57262390 0.89722475 5.90790629
C 6.81737613 8.52277523 0.90209378
C 1.01959799 8.99378373 5.95105534
C 0.44365317 8.09518316 0.04354179
C 4.13865312 6.03481667 6.76645828
C 6.94634683 3.38518320 3.36145818
C 4.13865302 8.09518314 3.36145840
C 3.25134692 3.38518330 0.04354172
C 0.44365312 6.03481680 3.44854181
C 3.25134694 1.32481683 3.44854166
C 4.71459796 5.13621624 0.85894466
C 6.37040204 4.28378370 4.26394470
C 4.71459806 8.99378370 4.26394474
C 2.67540204 4.28378373 5.95105538
C 1.01959796 5.13621630 2.54605532
C 2.67540194 0.42621627 2.54605529
C 3.12237615 5.60722456 5.90790637
C 0.57262383 3.81277531 2.50290624
C 3.12237604 8.52277526 2.50290643
C 4.26762388 3.81277542 0.90209362
C 6.81737614 5.60722467 4.30709374
C 4.26762394 0.89722472 4.30709365
H 6.60387371 2.35960826 6.73054386
H 5.56968034 0.74691993 1.52593899
H 1.01434081 1.59339679 5.19625918
H 6.37565919 7.82660320 1.61374085
H 1.82031966 8.67308006 5.28406104
H 0.78612630 7.06039173 0.07945617
H 4.48112628 7.06960836 6.73054385
H 6.60387368 2.35039169 3.32554380
H 4.48112633 7.06039163 3.32554387
H 2.90887372 2.35039162 0.07945618
H 0.78612632 7.06960829 3.48445623
H 2.90887367 2.35960835 3.48445616
H 5.51531957 5.45691993 1.52593892
H 5.56968038 3.96308001 4.93093892
H 5.51531958 8.67308007 4.93093888
H 1.87468043 3.96308005 5.28406111
H 1.82031962 5.45691998 1.87906111
H 1.87468042 0.74691991 1.87906115
H 2.68065919 6.30339674 5.19625914
H 1.01434083 3.11660328 1.79125911
H 2.68065912 7.82660315 1.79125910
H 4.70934081 3.11660323 1.61374088
H 6.37565917 6.30339671 5.01874091
H 4.70934088 1.59339683 5.01874093
#Benzene molecule
12
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 11.41535000 9.66832500 10.97953500
C 10.58467000 12.33172500 11.02047500
C 11.99903000 10.56740500 11.87250500
C 10.00100000 11.43261500 10.12750500
C 11.58370000 11.89910500 11.89295500
C 10.41635000 10.10087500 10.10701500
H 11.73936000 8.62955500 10.96361500
H 10.26066000 13.37044500 11.03640500
H 12.77822000 10.22990500 12.55304500
H 9.22178000 11.77011500 9.44696500
H 12.03887000 12.60043500 12.58950500
H 9.96113000 9.39956500 9.41049500
————————————————–
#CO2 solid
12
Lattice="5.624 0.0 0.0 0.0 5.624 0.0 0.0 0.0 5.624"
C 0.33737131 0.33737125 0.33737125
C 3.14937126 0.33737121 3.14937118
C 0.33737126 3.14937119 3.14937121
C 3.14937123 3.14937122 0.33737122
O 1.01211377 1.01211367 1.01211370
O 5.28662874 5.28662874 5.28662871
O 2.47462878 5.28662879 3.82411372
O 3.82411371 1.01211365 2.47462871
O 5.28662862 3.82411384 2.47462854
O 1.01211391 2.47462859 3.82411386
O 3.82411364 2.47462875 5.28662878
O 2.47462887 3.82411364 1.01211366
#CO2 molecule
3
Lattice="20.0 0.0 0.0 0.0 20.0 0.0 0.0 0.0 20.0"
C 10.00061500 9.99922500 10.00163500
O 10.67966500 9.32001500 9.33519500
O 9.32033500 10.67998500 10.66480500
————————————————–
#Cyanamide solid
40
Lattice="6.856 0.0 0.0 0.0 6.628 0.0 0.0 0.0 9.147"
N 0.98678911 1.10121243 0.99077714
N 5.86921305 5.52682299 8.15622040
N 2.44123171 5.52683243 5.56427784
N 4.41477435 1.10120445 3.58272460
N 5.86923013 4.41522049 3.58273232
N 0.98677058 2.21281036 5.56426921
N 4.41477470 2.21281058 8.15622196
N 2.44121109 4.41522122 0.99079308
N 1.00418807 6.60938087 3.20381811
N 5.85180871 0.01865656 5.94318052
N 2.42381641 0.01859504 7.77727817
N 4.43220989 6.60940496 1.36974230
N 5.85183345 3.29537075 1.36974155
N 1.00416241 3.33266396 7.77725785
N 4.43217819 3.33259595 5.94314838
N 2.42384593 3.29539420 3.20386558
C 0.99084076 0.49271138 2.14750428
C 5.86515902 6.13532592 6.99949613
C 2.43716021 6.13530272 6.72102533
C 4.41885426 0.49271529 2.42598724
C 5.86515277 3.80670123 2.42594728
C 0.99084508 2.82133178 6.72105241
C 4.41881034 2.82132239 6.99944631
C 2.43717779 3.80669979 2.14757469
H 1.44155719 0.67055139 0.17058773
H 5.41443985 5.95747474 8.97641252
H 1.98648545 5.95746271 4.74414103
H 4.86951020 0.67058557 4.40287378
H 5.41447961 3.98459053 4.40291523
H 1.44151673 2.64344230 4.74408475
H 4.86953587 2.64349042 8.97641347
H 1.98645601 3.98454595 0.17058653
H 0.31571373 1.87180537 0.86440283
H 6.54028750 4.75622829 8.28259175
H 3.11223508 4.75627221 5.43788177
H 3.74375951 1.87175865 3.70910561
H 6.54028342 5.18579686 3.70912097
H 0.31571250 1.44223840 5.43787943
H 3.74367631 1.44220161 8.28258266
H 3.11232348 5.18582400 0.86441911
#Cyanamide molecule
5
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
N 10.74996500 11.26105000 10.27863000
N 10.86924500 10.12084000 12.50888000
C 10.84030500 10.62328000 11.45798000
H 10.47311500 10.68276000 9.49112000
H 11.52688500 11.87916000 10.06258000
————————————————–
#Cytosine solid
5252
Lattice="13.044 0.0 0.0 0.0 9.496 0.0 0.0 0.0 3.814"
C 12.83107499 1.46376843 1.23794632
C 6.73492849 8.03221372 3.14494625
C 0.21291826 6.21178009 0.66907077
C 6.30910263 3.28421291 2.57606930
C 1.70547959 2.50687019 2.09939188
C 4.81650979 6.98914290 0.19237955
C 11.33851972 7.25483573 3.62161916
C 8.22751524 2.24114502 1.71462439
C 2.22843641 1.26156776 2.56715488
C 4.29357061 8.23443310 0.66015863
C 10.81557991 6.00955398 3.15384832
C 8.75044460 3.48643594 1.24685571
C 1.47708890 0.15122457 2.33346513
C 5.04491201 9.34477543 0.42646806
C 11.56690582 4.89921607 3.38753120
C 7.99910280 4.59677784 1.48054908
H 12.90497622 8.85152191 1.31903395
H 6.66103350 0.64446126 3.22603785
H 0.13902378 4.10353677 0.58797128
H 6.38298561 5.39246154 2.49497702
H 2.01521512 4.53678374 1.97546003
H 4.50677748 4.95923450 0.06845208
H 11.02877600 9.28474347 3.74554792
H 8.53725427 0.21125141 1.83855323
H 3.37048911 3.57895190 2.61472445
H 3.15149628 5.91705023 0.70771869
H 9.67349667 8.32692273 3.10628417
H 9.89254336 1.16907280 1.19928893
H 3.17784495 1.22154206 3.08849984
H 3.34415989 8.27446609 1.18150145
H 9.86617044 5.96952568 2.63249684
H 9.69985954 3.52647035 0.72550255
H 1.76095250 8.64035409 2.64050615
H 4.76106885 0.85564721 0.73350243
H 11.28307572 3.89233456 3.08049837
H 8.28294684 5.60365682 1.17350594
N 0.29137105 0.24386573 1.68094157
N 6.23064454 9.25213959 3.58792561
N 12.75265039 4.99184306 0.22608698
N 6.81336251 4.50414085 2.13308818
N 0.51536959 2.58763483 1.47237257
N 6.00661919 6.90836363 3.37936008
N 12.52862352 7.33562211 0.43464730
N 7.03740486 2.16036632 2.34165711
N 2.40229736 3.63827254 2.28936198
N 4.11967443 5.85773770 0.38234347
N 10.64166915 8.38624836 3.43164085
N 8.92435133 1.10974565 1.52466007
O 11.73477809 1.48662658 0.61793295
O 7.83123705 8.00935635 2.52494932
O 1.30922684 6.23463023 1.28907971
O 5.21277719 3.26134733 3.19606926
#Cytosine molecule
13
Lattice="25.0 0.0 0.0 0.0 25.0 0.0 0.0 0.0 22.0"
C 11.24786000 12.78985500 11.64078500
C 13.17995000 11.81944500 10.75268500
C 13.71462000 13.07304500 10.30327500
C 12.95730000 14.17489500 10.55414500
H 11.18849000 14.85318500 11.39457500
H 13.52822000 9.82129500 10.92847500
H 14.83162000 10.70315500 10.18711500
H 14.66445000 13.14725500 9.78518500
H 13.25509000 15.17870500 10.26230500
N 11.77133000 14.04717500 11.19433500
N 12.02305000 11.69031500 11.38235500
N 13.87564000 10.67414500 10.50889500
O 10.16838000 12.78283500 12.21481500
————————————————–
#Ethyl carbamate solid
26
Lattice="5.051 0.0 0.0 1.61883 6.82155 0.0 -1.89881 -1.07775 7.2201"
C 4.94843622 5.03868645 2.64153873
C -0.17728522 0.70496460 4.57865724
C 4.39308219 3.78967588 1.99505226
C 0.37805745 1.95398964 5.22510042
C 0.20252159 1.74281031 1.10683178
C 4.56847247 4.00089363 6.11328203
N 1.28873600 0.96878754 0.95087115
N 3.48237352 4.77479927 6.26928189
O 0.48145171 2.91027211 1.73336051
O 4.28965578 2.83335504 5.48677947
O 4.10717294 1.42486705 0.74292884
O 0.66391746 4.31882578 6.47703076
H 4.12460418 5.72648462 2.87648135
H 0.64658470 0.01720103 4.34375993
H 0.42570004 4.80065562 3.57368751
H 4.34549414 0.94290719 3.64645003
H 5.64428566 5.55594027 1.96830028
H -0.87312095 0.18765022 5.25188585
H 3.69174724 3.26460847 2.65941690
H 1.07939921 2.47902940 4.56073336
H 3.88354726 4.00550209 1.04757892
H 0.88758288 1.73815583 6.17257783
H 2.22575902 1.33808247 1.11945121
H 2.54533410 4.40553251 6.10071505
H 1.18581231 0.11386032 0.39366181
H 3.58527219 5.62993968 6.82643819
#Ethyl carbamate molecule
13
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 10.20352500 12.19071000 11.15459000
C 12.17506500 10.87041000 11.08975000
C 12.56559500 9.42006000 10.91172000
N 8.83649500 12.13133000 11.12503000
O 10.85947500 13.20349000 11.31353000
O 10.72612500 10.93578000 11.01325000
H 8.34400500 13.00833000 11.04008000
H 8.38117500 11.28726000 10.80669000
H 12.49306500 11.26833000 12.06130000
H 12.59878500 11.51269000 10.30793000
H 13.65599500 9.32217000 10.96549000
H 12.12410500 8.79651000 11.69710000
H 12.23315500 9.04133000 9.93870000
————————————————–
#Formamide solid
24
Lattice="3.604 0.0 0.0 0.0 9.041 0.0 -1.27456 0.0 6.87688"
C 0.86868335 0.49796107 1.76956771
C 1.46078838 8.54303893 5.10729956
C 0.29604336 5.01836482 1.66885272
C 2.03338466 4.02243212 5.20808014
O 1.39099161 8.40103458 1.70750974
O 0.93850318 0.63994271 5.16936693
O -0.22627431 3.88050592 1.73093786
O 2.55569758 5.16032638 5.14603239
N 0.91200333 1.41044869 0.80489020
N 1.41747311 7.63054479 6.07200168
N 0.25269332 5.93089010 2.63353882
N 2.07671371 3.10994660 4.24339014
H 0.49812091 2.33599769 0.97933043
H 1.83132413 6.70497823 5.89760088
H 0.66662493 6.85646147 2.45909899
H 1.66278004 2.18437354 4.41784395
H 0.10070188 1.19157059 6.78576607
H 2.22876790 7.84943228 0.09111393
H -0.21053509 5.71203241 3.52950647
H 2.53995202 3.32882087 3.34740403
H 0.33433629 0.81741912 2.68369519
H 1.99515332 8.22355938 4.19318480
H 0.83043791 5.33781192 0.75473835
H 1.49902295 3.70300371 6.12221516
#Formamide molecule
6
Lattice="20.0 0.0 0.0 0.0 20.0 0.0 0.0 0.0 20.0"
C 10.58759000 9.98113000 10.01158000
O 11.34070000 10.70746000 9.38703000
N 9.23423000 10.12246000 10.05831000
H 8.65930000 9.49550000 10.60397000
H 8.79391000 10.88372000 9.55515000
H 10.94198000 9.11628000 10.61297000
————————————————–
#Imidazole solid
36
Lattice="7.582 0.0 0.0 0.0 5.371 0.0 -4.7433 0.0 8.56418"
C 0.33729660 1.16812487 1.53226658
C 2.50140339 4.20287511 7.03191345
C 4.87305375 3.85362491 2.74982372
C -2.03435370 1.51737491 5.81435623
C 0.92261763 2.97476250 2.56311008
C 1.91608253 2.39623754 6.00106975
C 4.28773320 0.28926257 1.71897980
C -1.44903310 5.08173723 6.84520007
C 1.63393529 2.94163032 1.38697445
C 1.20476490 2.42936951 7.17720539
C 3.57641534 0.25613076 2.89511573
C -0.73771510 5.11486919 5.66906426
N 1.24794517 1.78824454 0.74211690
N 1.59075492 3.58275524 7.82206308
N 3.96240535 4.47374463 3.53997318
N -1.12370514 0.89725534 5.02420685
N 0.11121190 1.85960718 2.64921081
N 2.72748814 3.51139296 5.91496913
N 5.09913854 4.54510687 1.63287919
N -2.26043855 0.82589284 6.93130070
H -3.10238840 1.43135509 8.39660305
H 5.94108843 3.93964462 0.16757695
H 3.56943875 4.11685543 4.44966700
H -0.73073855 1.25414462 4.11451304
H -0.13519440 0.22445223 1.28500474
H 2.97389433 5.14654777 7.27917538
H 5.34554468 2.90995214 2.99708540
H -2.50684467 2.46104768 5.56709457
H 0.95135157 3.72625155 3.34275642
H 1.88734865 1.64474856 5.22142335
H 4.25899894 1.04075140 0.93933366
H -1.42029886 4.33024836 7.62484620
H 2.36706420 3.62428203 0.97583871
H 0.47163606 1.74671768 7.58834109
H 2.84328669 0.93878230 3.30625128
H -0.00458635 4.43221772 5.25792871
#Imidazole molecule
9
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 10.34888500 9.82964500 11.00015500
C 12.05692500 11.13122500 10.99943500
C 10.96063500 11.95890500 10.99986500
N 9.87032500 11.11220500 11.00084500
N 11.66705500 9.80854500 10.99976500
H 8.89782500 11.39232500 10.99941500
H 9.69610500 8.96604500 10.99965500
H 13.10217500 11.41135500 10.99915500
H 10.85327500 13.03395500 10.99915500
————————————————–
#Naphthalene solid
36
Lattice="8.0846 0.0 0.0 0.0 5.9375 0.0 -4.91153 0.0 7.1003"
C -0.94973915 0.11743516 2.34434104
C 4.12280915 5.82006484 4.75595897
C 0.08050915 3.08618512 4.75595941
C 3.09256057 2.85131481 2.34434067
C -0.18069041 0.97674390 1.58828068
C 3.35376039 4.96075611 5.51201933
C -0.68853999 3.94549402 5.51201981
C 3.86160968 1.99200591 1.58828026
C 0.20693460 0.63246278 0.26731594
C 2.96613539 5.30503723 6.83298406
C -1.07616418 3.60121341 6.83298500
C 4.24923388 2.33628652 0.26731509
C -3.92114814 1.49896467 6.56173323
C 7.09421811 4.43853534 0.53856676
C 3.05191766 4.46771482 0.53856792
C 0.12115207 1.46978513 6.56173219
C -3.55163422 1.13139694 5.28458738
C 6.72470421 4.80610307 1.81571263
C 2.68240326 4.10014667 1.81571343
C 0.49066648 1.83735330 5.28458667
H -1.24420859 0.40588482 3.35327114
H 4.41727857 5.53161518 3.74702886
H 0.37497846 3.37463495 3.74703023
H 2.79809125 2.56286501 3.35326987
H 0.13369636 1.94022491 1.98886185
H 3.03937358 3.99727512 5.11143815
H -1.00292639 4.90897510 5.11143829
H 4.17599609 1.02852488 1.98886180
H -3.61071009 2.45931442 6.97232726
H 6.78378002 3.47818560 0.12797274
H 2.74148016 5.42806396 0.12797299
H 0.43158959 0.50943599 6.97232709
H -2.93800303 1.80454192 4.68314386
H 6.11107300 4.13295810 2.41715615
H 2.06877153 4.77329223 2.41715672
H 1.10429822 1.16420776 4.68314336
#Naphthalene molecule
18
Lattice="25.0 0.0 0.0 0.0 25.0 0.0 0.0 0.0 20.0"
C 10.75943000 10.66175000 9.99986000
C 12.13611000 10.66289000 9.99967000
C 12.86236000 11.88117000 9.99974000
C 12.13744000 13.11907000 10.00005000
C 10.71974000 13.08188000 10.00038000
C 10.04504000 11.88190000 10.00018000
C 14.28022000 11.91822000 9.99954000
C 12.86373000 14.33727000 10.00022000
C 14.24050000 14.33842000 10.00010000
C 14.95482000 13.11832000 9.99971000
H 14.82925000 10.97742000 9.99944000
H 10.21474000 9.71991000 9.99991000
H 12.68835000 9.72395000 9.99945000
H 10.17105000 14.02285000 10.00056000
H 8.95724000 11.86783000 10.00049000
H 12.31181000 15.27634000 10.00053000
H 14.78552000 15.28009000 10.00015000
H 16.04276000 13.13255000 9.99967000
————————————————–
#Oxalic acid alpha solid
32
Lattice="6.548 0.0 0.0 0.0 7.844 0.0 0.0 0.0 6.086"
C 0.37583320 0.43232711 5.56714048
C 6.17216680 7.41167289 0.51885952
C 2.89816686 0.43232726 2.52414046
C 3.64983329 3.48967259 5.56714077
C 6.17216695 3.48967268 2.52414055
C 3.64983314 7.41167274 3.56185954
C 2.89816671 4.35432741 0.51885923
C 0.37583305 4.35432732 3.56185945
H 0.63014501 2.31842781 5.13526789
H 5.91785499 5.52557219 0.95073211
H 2.64385478 2.31842790 2.09226848
H 3.90414549 1.60357209 5.13526836
H 5.91785480 1.60357199 2.09226856
H 3.90414522 5.52557210 3.99373152
H 2.64385451 6.24042791 0.95073164
H 0.63014520 6.24042801 3.99373144
O 1.02885192 7.78797454 4.65332457
O 0.20000596 1.71027152 5.81226428
O 5.51914808 0.05602546 1.43267543
O 6.34799404 6.13372848 0.27373572
O 2.24514883 7.78797525 1.61032426
O 4.30285199 3.97802499 4.65332480
O 5.51914872 3.97802522 1.61032446
O 4.30285117 0.05602475 4.47567574
O 2.24514801 3.86597501 1.43267520
O 1.02885128 3.86597478 4.47567554
O 3.07399372 1.71027191 2.76926524
O 3.47400595 2.21172807 5.81226494
O 6.34799398 2.21172823 2.76926519
O 3.47400628 6.13372809 3.31673476
O 3.07399405 5.63227193 0.27373506
O 0.20000602 5.63227177 3.31673481
#Oxalic acid alpha molecule
8
Lattice="20.0 0.0 0.0 0.0 20.0 0.0 0.0 0.0 20.0"
C 10.36587000 9.59569000 9.45311500
C 9.63408000 10.40374000 10.54673500
H 9.27416000 8.21411000 10.07709500
H 10.72505000 11.78589000 9.92217500
O 11.21197000 10.09969000 8.74899500
O 8.78803000 9.90032000 11.25100500
O 9.96469000 8.32590000 9.38345500
O 10.03446000 11.67365000 10.61542500
————————————————–
#Oxalic acid beta solid
16
Lattice="5.33 0.0 0.0 0.0 6.015 0.0 -2.36848 0.0 4.89289"
C -1.59862081 0.01833967 4.88466362
C 4.56014081 5.99666033 0.00822638
C 3.37590051 3.02583970 2.45467197
C -0.41438051 2.98916030 2.43821803
H 2.31293959 5.40473072 0.93895207
H 0.64858041 0.61026928 3.95393793
H 1.83282006 2.39723053 1.50749338
H 1.12869994 3.61776947 3.38539662
O -0.98133805 0.63431893 4.01775147
O 1.29558040 5.36571883 0.99010253
O 3.94285805 5.38068107 0.87513853
O 1.66593960 0.64928117 3.90278747
O 2.75861824 3.64181890 3.32158390
O 0.20290176 2.37318110 1.57130611
O 2.85017950 2.35821859 1.45634322
O 0.11134050 3.65678142 3.43654678
#Oxalic acid beta molecule
8
Lattice="20.0 0.0 0.0 0.0 20.0 0.0 0.0 0.0 20.0"
C 10.36587000 9.59569000 9.45311500
C 9.63408000 10.40374000 10.54673500
H 9.27416000 8.21411000 10.07709500
H 10.72505000 11.78589000 9.92217500
O 11.21197000 10.09969000 8.74899500
O 8.78803000 9.90032000 11.25100500
O 9.96469000 8.32590000 9.38345500
O 10.03446000 11.67365000 10.61542500
————————————————–
#Pyrazine solid
20
Lattice="9.325 0.0 0.0 0.0 5.85 0.0 0.0 0.0 3.733"
N 1.40499064 5.84998041 3.73297772
N 7.92001424 0.00001959 0.00002228
N 6.06753258 2.92509006 1.86644313
N 3.25751491 2.92492431 1.86655294
C 0.69836538 1.04337826 0.46254872
C 0.69832735 4.80661044 3.27041876
C 8.62667265 1.04335779 0.46257865
C 8.62663679 4.80664948 3.27047302
C 5.36087000 1.88165371 2.32903541
C 3.96423188 1.88162545 2.32909675
C 3.96416917 3.96835664 1.40396090
C 5.36081816 3.96839334 1.40389856
H 1.26652668 1.89307486 0.85085658
H 1.26645924 3.95691268 2.88207739
H 8.05852889 1.89309050 0.85094731
H 8.05845493 3.95690589 2.88216080
H 5.92917440 1.03196080 2.71733985
H 3.39616265 1.03191180 2.71748655
H 3.39586849 4.81805766 1.01566459
H 5.92888770 4.81809866 1.01552052
#Pyrazine molecule
10
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
N 12.40806500 11.00001000 11.00021000
N 9.59193500 11.00003000 11.00019000
C 11.69754500 9.95150000 11.43245000
C 10.30240500 9.95149000 11.43252000
C 10.30245500 12.04847000 10.56756000
C 11.69764500 12.04854000 10.56762000
H 12.25709500 9.08625000 11.78912000
H 9.74341500 9.08610000 11.78931000
H 9.74341500 12.91390000 10.21069000
H 12.25707500 12.91372000 10.21078000
————————————————–
#Pyrazole solid
72
Lattice="8.19 0.0 0.0 0.0 12.588 0.0 0.0 0.0 6.773"
C 2.37238002 0.70669445 2.61975653
C 6.46740079 11.88136297 4.15317427
C 2.37238143 5.58728983 6.00626851
C 6.46741482 7.00067670 0.76670599
C 3.21047888 1.47171391 3.45257555
C 7.30547541 11.11630143 3.32038996
C 3.21047705 4.82226682 0.06609731
C 7.30549435 7.76570929 6.70689087
C 2.40361542 2.50055385 3.92012162
C 6.49859529 10.08747247 2.85283860
C 2.40359389 3.79344635 0.53364899
C 6.49862009 8.79453972 6.23933801
C 5.84191897 2.35717102 6.27863951
C 1.74697328 10.23080098 0.49432366
C 5.84197608 3.93683676 2.89216567
C 1.74695457 8.65119192 3.88083817
C 4.97070673 1.37375737 0.00735274
C 0.87575907 11.21423689 6.76562552
C 4.97073282 4.92023648 3.39386440
C 0.87573932 7.66777188 3.37913752
C 5.72638851 0.66428786 0.93058490
C 1.63142600 11.92369465 5.84237652
C 5.72638587 5.62971737 4.31711583
C 1.63140643 6.95829964 2.45589283
H 0.33388181 2.93712774 3.45397007
H 4.42886289 9.65094960 3.31899726
H 0.33386317 3.35688868 0.06747992
H 4.42888190 9.23108750 6.70550917
H 2.61802416 3.33652591 4.57458815
H 6.71300070 9.25149511 2.19839955
H 2.61800175 2.95747968 1.18811801
H 6.71301638 9.63051141 5.58487978
H 4.25276812 1.29728668 3.68354698
H 0.15778290 11.29069714 3.08943542
H 4.25275750 4.99668989 0.29705761
H 0.15778243 7.59129527 6.47591908
H 2.60116941 12.39469471 2.05639446
H 6.69619278 0.19337261 4.71653156
H 2.60118260 6.48727935 5.44289084
H 6.69620976 6.10068117 1.33007017
H 7.78136977 1.02587574 1.55639652
H 3.68640726 11.56210878 5.21654877
H 7.78138623 5.26818139 4.94293013
H 3.68639108 7.31987668 1.83007397
H 5.48106643 12.40663292 1.56174091
H 1.38611556 0.18136708 5.21124316
H 5.48104473 6.47537158 4.94825894
H 1.38608564 6.11263943 1.82475017
H 3.93715993 1.20228245 6.51128341
H 8.03221757 11.38573482 0.26171662
H 3.93718864 5.09168470 3.12478479
H 8.03219589 7.49628749 3.64822845
H 5.64637762 3.12299610 5.53698809
H 1.55141628 9.46499132 1.23597645
H 5.64646070 3.17100155 2.15051939
H 1.55141630 9.41701566 4.62248403
N 1.17467838 2.31769763 3.38131801
N 5.26966782 10.27037113 3.39162670
N 1.17465631 3.97630274 6.76785316
N 5.26968836 8.61166546 0.00514684
N 1.13306782 1.22732131 2.57208434
N 5.22807273 11.36077100 4.20083495
N 1.13307041 5.06668277 5.95860370
N 5.22809757 7.52128355 0.81438530
N 6.96009693 1.22528901 0.94517764
N 2.86512273 11.36265952 5.82776694
N 6.96010156 5.06872042 4.33170964
N 2.86511193 7.51932118 2.44129023
N 7.05384808 2.26635459 0.07941876
N 2.95888217 10.32161193 6.69353482
N 7.05387107 4.02767586 3.46594293
N 2.95887315 8.56037566 3.30705089
#Pyrazole molecule
9
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 11.01591500 11.87821500 11.66172500
C 10.13161500 10.89700500 11.16415500
C 10.86960500 10.20272500 10.22384500
H 10.62191500 9.36725500 9.58343500
H 9.10345500 10.71911500 11.44618500
H 10.83242500 12.63274500 12.41656500
H 12.89654500 10.52869500 9.63866500
N 12.10053500 10.77938500 10.20966500
N 12.21825500 11.80898500 11.08057500
————————————————–
#Triazine solid
54
Lattice="9.647 0.0 0.0 -4.8235 8.35455 0.0 0.0 0.0 7.281"
C -0.65235583 1.12991458 1.82024997
C 5.47585596 7.22463544 5.46074985
C 4.17114312 7.22463397 1.82024946
C 0.65235762 1.12991641 5.46075067
C 1.30471321 0.00000018 1.82025006
C 3.51878737 8.35454985 5.46074955
C 4.17093746 3.91467714 4.24717658
C 5.47567719 1.65480059 0.60667625
C 4.17132180 1.65479939 4.24717607
C 5.47606364 3.91467857 0.60667673
C 6.12824050 2.78507284 4.24717625
C 3.51875967 2.78507236 0.60667642
C -0.65217675 6.69974979 6.67432374
C 0.65256302 4.43987253 3.03382330
C -0.65256401 4.43987141 6.67432375
C 0.65217880 6.69975102 3.03382334
C 1.30474087 5.56947740 6.67432370
C -1.30474020 5.56947714 3.03382359
H 8.44845324 2.07594425 1.82025026
H -3.62495283 6.27860577 5.46074975
H 3.62495264 6.27860452 1.82024979
H 1.19854785 2.07594557 5.46075032
H -2.42640502 8.35454989 1.82024993
H 7.24990554 0.00000011 5.46074993
H 3.62481769 4.86067365 4.24726822
H 6.02187490 0.70884918 0.60676776
H 3.62512506 0.70884813 4.24726774
H 6.02218264 4.86067459 0.60676831
H 7.22055738 2.78502755 4.24726785
H 2.42644271 2.78502761 0.60676828
H -1.19837445 7.64570093 6.67423232
H 1.19868264 3.49387636 3.03373160
H -1.19868258 3.49387533 6.67423194
H 1.19837551 7.64570193 3.03373186
H 2.39705770 5.56952212 6.67423186
H -2.39705718 5.56952264 3.03373203
N 3.44794953 8.35454968 1.82025019
N 1.37555106 0.00000050 5.46074993
N -4.13572481 7.16328837 1.82024958
N -0.68777450 1.19126185 5.46075034
N 0.68777606 1.19126208 1.82025009
N 4.13572442 7.16328812 5.46074957
N 3.44795759 2.78455816 4.24723519
N 6.19904226 2.78455894 0.60673497
N 5.51152337 1.59374116 4.24723453
N 4.13598173 3.97625069 0.60673557
N 5.51101884 3.97625082 4.24723510
N 4.13547576 1.59374102 0.60673496
N -1.37554199 5.56999124 6.67426528
N 1.37554286 5.56999203 3.03376449
N 0.68751824 4.37829896 6.67426461
N -0.68802301 6.76080886 3.03376517
N 0.68802476 6.76080851 6.67426520
N -0.68751835 4.37829937 3.03376475
#Triazine molecule
9
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 9.91484000 9.91148500 10.99987000
C 11.78950000 11.14893500 10.99987000
C 9.78050000 12.15370500 10.99993000
H 12.87815000 11.21446500 10.99981000
H 9.42702000 8.93600500 10.99979000
H 9.17989000 13.06399500 10.99980000
N 11.25283000 9.92324500 10.99988000
N 9.12185000 10.98906500 10.99979000
N 11.11021000 12.30179500 11.00021000
————————————————–
#Trioxane solid
72
Lattice="9.32 0.0 0.0 -4.66 8.07136 0.0 0.0 0.0 8.196"
C 0.56242606 1.21971970 8.06617326
C 3.32304792 7.94752329 8.06617957
C -3.88371403 6.97437796 8.06615026
C 3.88490521 6.97442470 3.96817326
C -0.56123035 1.21975328 3.96817957
C -3.32184309 7.94756738 3.96815026
C 5.22320752 3.90969515 2.60276186
C 3.32310867 2.56751274 2.60276308
C 5.43550948 1.59307845 2.60278213
C 3.88570980 1.59308021 6.70076186
C 4.09802396 3.90970595 6.70076308
C 5.99810888 2.56752960 6.70078213
C 0.56285368 6.60029444 5.33396527
C -1.33692143 5.25764647 5.33397494
C 0.77573782 4.28371321 5.33393003
C -0.77459352 4.28376700 1.23596527
C -0.56171430 6.60034515 1.23597494
C 1.33806593 5.25769447 1.23593003
H 0.56889287 1.23152076 6.95995251
H 3.30960026 7.94727271 6.95996112
H -3.87676292 6.96285105 6.95993453
H 3.87791860 6.96292374 2.86195251
H -0.56773717 1.23152460 2.86196112
H -3.30838493 7.94731100 2.86193453
H 5.22940201 3.92100379 1.49664673
H 3.31023327 2.56722229 1.49664747
H 5.44222006 1.58204116 1.49666753
H 3.87901348 1.58206130 5.59464673
H 4.09183781 3.92100160 5.59464747
H 6.01102275 2.56723670 5.59466753
H 0.56924717 6.61194364 4.22786142
H -1.35019210 5.25745110 4.22786453
H 0.78257594 4.27232307 4.22782043
H -0.78148528 4.27240547 0.12986142
H -0.56818043 6.61193558 0.12986453
H 1.35134914 5.25746755 0.12982043
H 0.98609856 2.13494696 0.29091773
H 2.31860250 7.85680929 0.29091918
H -3.30292666 6.14986448 0.29089202
H 3.30413172 6.14989978 4.38891773
H -0.98489246 2.13498589 4.38891918
H -2.31740006 7.85684731 4.38889202
H 5.64746374 4.82487170 3.02304796
H 2.31841988 2.47735361 3.02305364
H 6.01595670 0.76807791 3.02305733
H 3.30527208 0.76807513 7.12104796
H 3.67375964 4.82487187 7.12105364
H 7.00280363 2.47734763 7.12105733
H 0.98693826 7.51541780 5.75471944
H -2.34145965 5.16733580 5.75470317
H 1.35621756 3.45890274 5.75466147
H -1.35507099 3.45893715 1.65671944
H -0.98577210 7.51545645 1.65670317
H 2.34261234 5.16738930 1.65666147
O 1.34879253 0.12379262 0.34052837
O 8.53896985 1.10511505 0.34060865
O 4.09400830 6.84133073 0.34055552
O 5.22718875 6.84137463 4.43852837
O 7.97242760 0.12383470 4.43860865
O 0.78224032 1.10517803 4.43855552
O 6.00914509 2.81310390 3.07319249
O 3.87982019 3.79647340 3.07320501
O 4.09284977 1.46074976 3.07319719
O 5.22835408 1.46073367 7.17119249
O 3.31206901 2.81309911 7.17120501
O 5.44137899 3.79647183 7.17119719
O 1.34895489 5.50387932 5.80402312
O -0.78043047 6.48661686 5.80412394
O -0.56684522 4.15112973 5.80404403
O 0.56798005 4.15119067 1.70602312
O -1.34778797 5.50392446 1.70612394
O 0.78159503 6.48669769 1.70604403
#Trioxane molecule
12
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 9.75943500 10.23301500 10.48981500
C 11.66973500 11.53522500 10.48909500
C 9.76111500 12.28259500 11.55955500
H 12.75628500 11.48690500 10.57994500
H 9.41112500 10.69645500 9.54435500
H 9.40757500 9.20382500 10.57990500
H 9.41107500 12.79617500 12.45662500
H 9.41144500 12.79398500 10.63977500
H 11.36588500 12.02818500 9.54337500
O 11.17737500 10.20522500 10.50813500
O 11.17926500 12.28295500 11.59037500
O 9.24371500 10.96230500 11.59172500
————————————————–
#Uracil solid
48
Lattice="11.938 0.0 0.0 0.0 12.376 0.0 -1.8771 0.0 3.1364"
C 1.78225622 2.59429758 0.00574313
C 8.27862796 9.78170004 3.13064003
C 2.30947595 8.78217817 3.13070298
C 7.75142237 3.59381922 0.00569702
C 2.08435392 0.14277921 0.11203804
C 7.97654185 12.23322079 3.02437106
C 2.00753325 6.33070352 3.02422188
C 8.05334757 6.04530388 0.11218645
C 3.49427918 0.34926312 0.25303856
C 6.56661499 12.02674350 2.88336387
C 0.59759831 6.53708848 2.88324882
C 9.46328674 5.83891832 0.25316402
C 3.97708648 1.62332073 0.25591104
C 6.08380215 10.75269009 2.88047582
C 0.11466880 7.81109519 2.88040657
C 9.94622034 4.56491532 0.25598942
H 5.03601501 1.86086943 0.34067352
H 5.02487175 10.51514907 2.79570684
H -0.94426597 8.04859019 2.79567310
H 11.00515462 4.32742414 0.34071883
H 3.55800472 3.66468878 0.09183989
H 6.50287158 8.71132352 3.04454121
H 0.53370246 9.85246089 3.04448938
H 9.52719652 2.52354487 0.09191202
H -1.59771100 1.18094491 3.05919882
H 11.65860468 11.19504198 0.07721175
H 5.68954995 7.36893421 0.07722164
H 4.37133923 5.00706054 3.05918654
H 4.14803206 11.86043705 0.33011604
H 5.91286997 0.51557388 2.80628931
H -0.05613653 5.67221686 2.80614055
H 10.11701886 6.70379140 0.33026704
N 3.15416454 2.70636101 0.13227215
N 6.90671928 9.66964452 3.00410640
N 0.93755944 8.89415270 3.00405129
N 9.12333732 3.48185324 0.13234143
N 1.31181370 1.29183053 0.00666728
N 8.74907549 11.08416448 3.12973953
N 2.78001716 7.47975718 3.12972506
N 7.28087082 4.89623760 0.00668009
O -0.84489623 3.56668612 3.03878249
O 10.90577388 8.80930236 0.09757908
O 4.93652294 9.75463598 0.09784350
O 5.12437551 2.62136045 3.03855840
O 1.51190013 11.39754441 0.07574834
O 8.54899792 0.97845444 3.06067651
O 2.58005529 5.20945840 3.06030010
O 7.48082512 7.16654161 0.07613823
#Uracil molecule
12
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 10.18885000 9.77116500 11.00021000
C 12.29376000 11.15610500 11.00006000
C 11.45036000 12.33994500 10.99914000
C 10.10477000 12.21263500 10.99909000
H 12.11392000 9.08670500 10.99942000
H 8.48348000 10.89748500 10.99908000
H 11.93069000 13.31037500 10.99904000
H 9.43296000 13.06643500 10.99885000
N 9.49330000 10.98326500 10.99992000
N 11.56305000 9.94220500 11.00020000
O 13.51652000 11.13553500 11.00115000
O 9.62653000 8.68962500 11.00078000
————————————————–
#Urea solid
16
Lattice="5.565 0.0 0.0 0.0 5.565 0.0 0.0 0.0 4.684"
C 0.00000082 2.37694268 1.52725882
C 2.78249961 5.15943899 3.15674210
O 5.56499918 2.37694144 2.80034008
O 2.78249958 5.15943957 1.88366086
N 0.81701025 3.19393841 0.82848252
N 4.74799034 1.55994645 0.82848382
N 3.59951001 4.34244250 3.85551749
N 1.96548988 0.41143555 3.85551629
H 1.44737778 3.82432890 1.32525221
H 4.11762001 0.92955187 1.32525286
H 4.22987798 3.71205169 3.35874627
H 1.33512097 1.04182830 3.35874594
H 0.81111773 3.18805976 4.49317523
H 4.75388025 1.56582130 4.49317429
H 3.59361857 4.34832031 0.19082520
H 1.97137967 0.40556043 0.19082477
#Urea molecule
8
Lattice="22.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 22.0"
C 11.13769000 11.49895000 11.00094000
O 11.74707000 12.55972000 11.00028000
N 9.78540000 11.40471000 10.69863000
N 11.73819000 10.28413000 11.30402000
H 9.24993000 10.65093000 11.11422000
H 9.31407000 12.30128000 10.68780000
H 11.35317000 9.44028000 10.89551000
H 12.75007000 10.32741000 11.31220000
————————————————–
#Hexamine solid
22
Lattice="-3.4763251 3.4763251 3.4763251 3.4763251 -3.4763251 3.4763251
3.4763251 3.4763251 -3.4763251"
H 2.63776255 0.95716255 -0.31903745
H -0.31903745 2.63776255 0.95716255
H 4.95296255 0.95716255 0.95716255
H -0.31903745 0.95716255 2.63776255
H 0.95716255 2.63776255 -0.31903745
H 0.95716255 -0.31903745 2.63776255
H 1.47666255 3.15726255 3.15726255
H 3.15726255 1.47666255 3.15726255
H 0.95716255 4.95296255 0.95716255
H 2.63776255 -0.31903745 0.95716255
H 0.95716255 0.95716255 4.95296255
H 3.15726255 3.15726255 1.47666255
C 2.00886255 0.31906255 0.31906255
C 0.31906255 2.00886255 0.31906255
C 5.58196255 0.31906255 0.31906255
C 0.31906255 0.31906255 2.00886255
C 0.31906255 5.58196255 0.31906255
C 0.31906255 0.31906255 5.58196255
N 1.18656255 1.18656255 1.18656255
N 2.92786255 -2.28973745 2.92786255
N 2.92786255 2.92786255 -2.28973745
N -2.28973745 2.92786255 2.92786255
#Hexamine molecule
22
Lattice="25.0 0.0 0.0 0.0 25.0 0.0 0.0 0.0 25.0"
H 14.29000000 11.54825000 11.29875000
H 12.82950000 11.03195000 10.40445000
H 10.86810000 10.33855000 11.60575000
H 10.86810000 10.33855000 13.39415000
H 14.29000000 11.54825000 13.70115000
H 12.82950000 11.03195000 14.59545000
H 10.86810000 12.41885000 10.40445000
H 10.86810000 13.96775000 11.29875000
H 14.29000000 13.62885000 12.49995000
H 12.82950000 14.66145000 12.49995000
H 10.86810000 12.41885000 14.59555000
H 10.86810000 13.96775000 13.70115000
C 13.18860000 11.55265000 11.30635000
C 11.23960000 10.86365000 12.49995000
C 13.18860000 11.55265000 13.69355000
C 11.23970000 12.93085000 11.30625000
C 13.18860000 13.62005000 12.49995000
C 11.23970000 12.93085000 13.69375000
N 12.71540000 10.82355000 12.49995000
N 12.71550000 12.95085000 11.27165000
N 10.71000000 12.24185000 12.49995000
N 12.71550000 12.95085000 13.72815000
————————————————–
#Succinic acid solid
112
Lattice="10.9317762 0.0 -0.0129284 0.0 8.7402311 0.0 -0.292297 0.0 10.2113924"
C 0.30811980 8.14946555 4.94731594
C 5.01171980 0.59066555 0.15191594
C 0.38111980 4.96076555 2.39451594
C 4.93861980 3.77936555 2.70481594
C 1.32351980 8.44676555 3.87141594
C 3.99631980 0.29346555 1.22781594
C 1.39651980 4.66356555 1.31851594
C 3.92321980 4.07666555 3.78071594
C 0.16197130 8.14946555 10.05301214
C 4.86557130 0.59066555 5.25761214
C 0.23497130 4.96076555 7.50021214
C 4.79247130 3.77936555 7.81051214
C 1.17737130 8.44676555 8.97711214
C 3.85017130 0.29346555 6.33351214
C 1.25037130 4.66356555 6.42421214
C 3.77707130 4.07666555 8.88641214
C 5.77400790 8.14946555 4.94085174
C 10.47760790 0.59066555 0.14545174
C 5.84700790 4.96076555 2.38805174
C 10.40450790 3.77936555 2.69835174
C 6.78940790 8.44676555 3.86495174
C 9.46220790 0.29346555 1.22135174
C 6.86240790 4.66356555 1.31205174
C 9.38910790 4.07666555 3.77425174
C 5.62785940 8.14946555 10.04654794
C 10.33145940 0.59066555 5.25114794
C 5.70085940 4.96076555 7.49374794
C 10.25835940 3.77936555 7.80404794
C 6.64325940 8.44676555 8.97064794
C 9.31605940 0.29346555 6.32704794
C 6.71625940 4.66356555 6.41774794
C 9.24295940 4.07666555 8.87994794
H 5.18881980 7.27716555 4.60381594
H 0.13091980 1.46296555 0.49551594
H 5.26191980 5.83316555 2.05091594
H 0.05781980 2.90706555 3.04831594
H 0.99921980 7.80176555 0.72891594
H 4.32061980 0.93846555 4.37031594
H 0.92611980 5.30856555 3.28181594
H 4.39361980 3.43166555 1.81751594
H 2.91771980 7.72996555 3.02561594
H 2.40201980 1.01016555 2.07371594
H 2.99081980 5.38026555 0.47271594
H 2.32901980 3.35986555 4.62651594
H 5.04267130 7.27716555 9.70951214
H -0.01522870 1.46296555 5.60121214
H 5.11577130 5.83316555 7.15661214
H -0.08832870 2.90706555 8.15401214
H 0.85307130 7.80176555 5.83461214
H 4.17447130 0.93846555 9.47601214
H 0.77997130 5.30856555 8.38751214
H 4.24747130 3.43166555 6.92321214
H 2.77157130 7.72996555 8.13131214
H 2.25587130 1.01016555 7.17941214
H 2.84467130 5.38026555 5.57841214
H 2.18287130 3.35986555 9.73221214
H 10.65470790 7.27716555 4.59735174
H 5.59680790 1.46296555 0.48905174
H 10.72780790 5.83316555 2.04445174
H 5.52370790 2.90706555 3.04185174
H 6.46510790 7.80176555 0.72245174
H 9.78650790 0.93846555 4.36385174
H 6.39200790 5.30856555 3.27535174
H 9.85950790 3.43166555 1.81105174
H 8.38360790 7.72996555 3.01915174
H 7.86790790 1.01016555 2.06725174
H 8.45670790 5.38026555 0.46625174
H 7.79490790 3.35986555 4.62005174
H 10.50855940 7.27716555 9.70304794
H 5.45065940 1.46296555 5.59474794
H 10.58165940 5.83316555 7.15014794
H 5.37755940 2.90706555 8.14754794
H 6.31895940 7.80176555 5.82814794
H 9.64035940 0.93846555 9.46954794
H 6.24585940 5.30856555 8.38104794
H 9.71335940 3.43166555 6.91674794
H 8.23745940 7.72996555 8.12484794
H 7.72175940 1.01016555 7.17294794
H 8.31055940 5.38026555 5.57194794
H 7.64875940 3.35986555 9.72574794
O 1.27951980 0.70906555 3.14441594
O 4.04031980 8.03106555 1.95481594
O 1.35261980 3.66096555 0.59161594
O 3.96721980 5.07916555 4.50771594
O 2.25881980 7.51926555 3.77841594
O 3.06091980 1.22086555 1.32081594
O 2.33191980 5.59096555 1.22551594
O 2.98781980 3.14916555 3.87371594
O 1.13337130 0.70906555 8.25011214
O 3.89417130 8.03106555 7.06051214
O 1.20647130 3.66096555 5.69731214
O 3.82107130 5.07916555 9.61341214
O 2.11267130 7.51926555 8.88411214
O 2.91477130 1.22086555 6.42651214
O 2.18577130 5.59096555 6.33121214
O 2.84167130 3.14916555 8.97941214
O 6.74540790 0.70906555 3.13795174
O 9.50620790 8.03106555 1.94835174
O 6.81850790 3.66096555 0.58515174
O 9.43310790 5.07916555 4.50125174
O 7.72470790 7.51926555 3.77195174
O 8.52680790 1.22086555 1.31435174
O 7.79780790 5.59096555 1.21905174
O 8.45370790 3.14916555 3.86725174
O 6.59925940 0.70906555 8.24364794
O 9.36005940 8.03106555 7.05404794
O 6.67235940 3.66096555 5.69084794
O 9.28695940 5.07916555 9.60694794
O 7.57855940 7.51926555 8.87764794
O 8.38065940 1.22086555 6.42004794
O 7.65165940 5.59096555 6.32474794
O 8.30755940 3.14916555 8.97294794
#Succinic acid molecule
14
Lattice="25.0 0.0 0.0 0.0 25.0 0.0 0.0 0.0 25.0"
H 14.11975000 15.46600000 11.93510000
H 12.78155000 9.53400000 13.87910000
H 12.43075000 11.33220000 10.96430000
H 10.77975000 11.35030000 11.58510000
H 11.26695000 13.64630000 10.87690000
H 11.27085000 13.66630000 12.64070000
C 11.79605000 11.73530000 11.76590000
C 11.79605000 13.26260000 11.76380000
C 13.20035000 13.84150000 11.73820000
C 12.27005000 11.15750000 13.08830000
O 14.22025000 13.22590000 11.50900000
O 13.18995000 15.18010000 11.98440000
O 12.41625000 11.77360000 14.12310000
O 12.49785000 9.81900000 12.99210000

## References

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