CCSD(T)/CBS fragment-based calculations of lattice energy of molecular crystals

Abstract

A comparative study of the lattice energy calculations for a data set of 25 molecular crystals is performed using an additive scheme based on the individual energies of up to four-body interactions calculated using the coupled clusters with iterative treatment of single and double excitations and perturbative triples correction (CCSD(T)) with an estimated complete basis set (CBS) description. The CCSD(T)/CBS values on lattice energies are used to estimate sublimation enthalpies which are compared with critically assessed and thermodynamically consistent experimental values. The average absolute percentage deviation of calculated sublimation enthalpies from experimental values amounts to 13% (corresponding to 4.8 kJ mol(-1) on absolute scale) with unbiased distribution of positive to negative deviations. As pair interaction energies present a dominant contribution to the lattice energy and CCSD(T)/CBS calculations still remain computationally costly, benchmark calculations of pair interaction energies defined by crystal parameters involving 17 levels of theory, including recently developed methods with local and explicit treatment of electronic correlation, such as LCC and LCC-F12, are also presented. Locally and explicitly correlated methods are found to be computationally effective and reliable methods enabling the application of fragment-based methods for larger systems.

State-of-the-Art Calculations of Sublimation Enthalpies for Selected Molecular Crystals and Their Computational Uncertainty

“…Critically assessed experimental data, used in this work as a benchmark set for validation of the computational methodology, were developed by multi-property thermodynamic correlations in our previous work 17 which provides details on this procedure and the estimation of uncertainties of reference experimental data as well as a list of primary sources of experimental 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 13 thermodynamic data (see Table III in ref. 17 …”

“…Our previous study 17 and several other groups [26][27][28][29] showed that MP2 and DFT-D3 based calculations predominantly yielded overestimated cr coh E results when compared to their CCSD(T) analogues, commonly accepted as the gold standard for computational data. 30 The effect of extrapolations towards the complete basis set (CBS) 31 17,19,20,32 Using the fragment based approaches, it turns out to be important to include some of the multi-body interaction terms (typically three-body terms).…”

“…[12][13][14][15] cr coh E can be computed from the first principles either by a fragment based additive approach or by calculations with periodic boundary conditions. [16][17][18][19][20][21] In our previous work, 17 Table IV in ref. 17 , it can be seen that the difference of cr coh E for the same crystal calculated using various ab initio or DFT methods can amount to a few tens of percent.…”

“…[16][17][18][19][20][21] In our previous work, 17 Table IV in ref. 17 , it can be seen that the difference of cr coh E for the same crystal calculated using various ab initio or DFT methods can amount to a few tens of percent. While quantum calculations with periodic boundary conditions for molecular crystals are limited to the density functional theory methods relying mostly on semi-empirical correction for dispersion interactions, such as the DFT-D3 method by…”

Ab initiothermodynamic properties and their uncertainties for crystalline α-methanol

“…[57][58][59][60][61][62][63] The energies of monomers and spatially proximal dimers are computed via electronic structure theory, while long-range dimers and clusters consisting of larger numbers of molecules (many-body effects) are treated with a computationally inexpensive classical polarizable force field. In this work, the treatment of individual dimers (molecular pairs) was smoothly switched from quantum to classical over the intermolecular distance separation of 9 and 10 Å.…”