Sawicki Igor, Triglione Vincenzo, Jana Subrata, Śmiga Szymon
Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, ul. Grudzia̧dzka 5, 87-100 Toruń, Poland.
J Chem Theory Comput. 2025 Mar 25;21(6):2928-2941. doi: 10.1021/acs.jctc.4c01547. Epub 2025 Mar 6.
Møller-Plesset second-order (MP2) perturbation energy expression has been a workhorse for quantum chemistry methods for many years due to its very appealing accuracy/cost ratio compared to more advanced methods. It has been widely utilized in the post-Hartree-Fock (post-HF) calculations and Kohn-Sham density functional theory (KS-DFT) to define, e.g., the double-hybrid class of density functional approximations. Although the list of successful applications of the MP2 method is quite long, it suffers from various limitations, e.g., in strongly correlated systems, divergence in small energy gap systems, or overestimation of binding energies for large noncovalently bonded species. In this work, we analyze a few of the most commonly utilized forms of regularized MP2 correlation energy expression in the context of post-HF and KS-DFT calculations. To this end, we perform various tests for model systems, e.g., homogeneous electron gas, one-dimensional Hubbard model, Harmonium atoms, and some real-life examples, to trace back the advantages and disadvantages of these formulas, providing practical guidelines for their utilization in everyday quantum chemical calculations.
多年来，莫勒-普莱塞二阶（MP2）微扰能量表达式一直是量子化学方法的主力军，因为与更先进的方法相比，它具有非常吸引人的精度/成本比。它已被广泛应用于后哈特里-福克（post-HF）计算和科恩-沙姆密度泛函理论（KS-DFT）中，例如用于定义密度泛函近似的双杂化类。尽管MP2方法的成功应用列表很长，但它存在各种局限性，例如在强关联系统中、小能隙系统中的发散，或对大的非共价键合物种结合能的高估。在这项工作中，我们在post-HF和KS-DFT计算的背景下分析了几种最常用的正则化MP2相关能量表达式形式。为此，我们对模型系统进行了各种测试，例如均匀电子气、一维哈伯德模型、谐振子原子以及一些实际例子，以追溯这些公式的优缺点，为它们在日常量子化学计算中的应用提供实用指南。
