Faculty of Physics, Astronomy and Applied Informatics, Institute of Physics, Nicolas Copernicus University in Torun, Grudziadzka 5/7, Torun87-100, Poland.
Quantum Chemistry Laboratory, Faculty of Chemistry, University of Warsaw, Pasteura 1, Warsaw02-093, Poland.
J Chem Theory Comput. 2023 Feb 28;19(4):1177-1185. doi: 10.1021/acs.jctc.2c00902. Epub 2023 Feb 3.
We present a new method of calculation of the dispersion energy in the second-order symmetry-adapted perturbation theory. Using the Longuet-Higgins integral and time-independent coupled-cluster response theory, one shows that the general expression for the dispersion energy can be written in terms of cluster amplitudes and the excitation operators σ, which can be obtained by solving a linear equation. We introduced an approximate scheme dubbed CCPP2(T) for the dispersion energy accurate to the second order of intramonomer correlation, which includes certain classes to be summed to infinity. Assessment of the accuracy of the CCPP2(T) dispersion energy against the FCI dispersion for He demonstrates its high accuracy. For more complex systems, CCPP2(T) matches the accuracy of the best methods introduced for calculations of dispersion so far. The method can be extended to higher-order levels of excitations, providing a systematically improvable theory of dispersion interaction.
我们提出了一种在二阶对称自适应微扰理论中计算色散能的新方法。利用朗格特-欣金斯积分和时不变耦合簇响应理论，我们表明色散能的一般表达式可以用簇振幅和激发算符σ表示，而σ可以通过求解线性方程得到。我们引入了一种称为 CCPP2(T)的近似方案，用于色散能的计算，其精度可达到单体相关性的二阶，其中包括要被无穷求和的某些类。对 CCPP2(T)色散能与 FCI 色散对 He 的评估表明其具有很高的精度。对于更复杂的系统，CCPP2(T)与迄今为止引入的用于计算色散的最佳方法的精度相匹配。该方法可以扩展到更高阶的激发水平，提供一种可系统改进的色散相互作用理论。
