Syty Krystyna, Czekało Grzegorz, Pham Khanh Ngoc, Modrzejewski Marcin
University of Warsaw Faculty of Chemistry, Pasteura 1, 02-093 Warsaw, Poland.
Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, CZ-12116 Prague 2, Czech Republic.
J Chem Theory Comput. 2025 Jun 10;21(11):5533-5544. doi: 10.1021/acs.jctc.5c00428. Epub 2025 May 29.
The many-body expansion (MBE) of the lattice energy enables an ab initio description of molecular solids using correlated wave function approximations. However, the practical application of MBE requires computing the large number of -body contributions efficiently. To this end, we employ a multi-level coupled-cluster approach which adapts the approximation level based on interaction type and intermolecular distance. The high-level method, including connected triple excitations, is applied only to monomer relaxation and dimer interactions roughly within the first and second coordination shells. Long-range dimers and trimers are treated using a simplified coupled-cluster description based on the random-phase approximation (RPA). A key feature is an energy correction which mitigates the underbinding error of the base RPA. Convergence to the bulk limit is accelerated by the addition of the periodic Hartree-Fock correction. The proposed approach is validated against recent diffusion Monte Carlo reference data for the X23 data set, achieving a mean absolute error of 3.1 kJ/mol, i.e., chemical accuracy for absolute lattice energies.
晶格能的多体展开（MBE）使得能够使用相关波函数近似对分子固体进行从头算描述。然而，MBE的实际应用需要高效地计算大量的多体贡献。为此，我们采用了一种多级耦合簇方法，该方法根据相互作用类型和分子间距离调整近似水平。高级方法，包括连接三重激发，仅应用于单体弛豫和大致在第一和第二配位壳内的二聚体相互作用。长程二聚体和三聚体使用基于随机相位近似（RPA）的简化耦合簇描述进行处理。一个关键特征是能量校正，它减轻了基础RPA的欠结合误差。通过添加周期性哈特里-福克校正，加速了向体相极限的收敛。针对X23数据集的最新扩散蒙特卡罗参考数据对所提出的方法进行了验证，平均绝对误差为3.1 kJ/mol，即绝对晶格能的化学精度。
