Nguyen Anh L P, Mason Thomas G, Freeman Benny D, Izgorodina Ekaterina I
School of Chemistry, Monash University, Clayton, Victoria, Australia.
Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas, USA.
J Comput Chem. 2021 Feb 5;42(4):248-260. doi: 10.1002/jcc.26452. Epub 2020 Nov 24.
We present an inexpensive and robust theoretical approach based on the fragment molecular orbital methodology and the spin-ratio scaled second-order Møller-Plesset perturbation theory to predict the lattice energy of benzene crystals within 2 kJ⋅mol . Inspired by the Harrison method to estimate the Madelung constant, the proposed approach calculates the lattice energy as a sum of two- and three-body interaction energies between a reference molecule and the surrounding molecules arranged in a sphere. The lattice energy converges rapidly at a radius of 13 Å. Adding the corrections to account for a higher correlated level of theory and basis set superposition for the Hartree Fock (HF) level produced a lattice energy of -57.5 kJ⋅mol for the benzene crystal structure at 138 K. This estimate is within 1.6 kJ⋅mol off the best theoretical prediction of -55.9 kJ⋅mol . We applied this approach to calculate lattice energies of the crystal structures of phase I and phase II-polymorphs of benzene-observed at a higher temperature of 295 K. The stability of these polymorphs was correctly predicted, with phase II being energetically preferred by 3.7 kJ⋅mol over phase I. The proposed approach gives a tremendous potential to predict stability of other molecular crystal polymorphs.
我们提出了一种基于片段分子轨道方法和自旋比缩放二阶莫勒-普莱塞特微扰理论的廉价且稳健的理论方法，用于预测苯晶体在2 kJ·mol范围内的晶格能。受哈里森方法估算马德隆常数的启发，该方法将晶格能计算为参考分子与排列在球体内的周围分子之间两体和三体相互作用能的总和。晶格能在半径为13 Å时迅速收敛。对更高相关理论水平和哈特里-福克（HF）水平的基组叠加进行校正后，得到138 K时苯晶体结构的晶格能为-57.5 kJ·mol。该估计值与最佳理论预测值-55.9 kJ·mol相差1.6 kJ·mol以内。我们应用此方法计算了在295 K较高温度下观察到的苯的I相和II相多晶型物晶体结构的晶格能。这些多晶型物的稳定性得到了正确预测，II相比I相在能量上更优3.7 kJ·mol。所提出的方法为预测其他分子晶体多晶型物的稳定性提供了巨大潜力。
