Sharma Prachi, Jenkins Andrew J, Scalmani Giovanni, Frisch Michael J, Truhlar Donald G, Gagliardi Laura, Li Xiaosong
Department of Chemistry, University of Washington, Seattle, Washington 98195, United States.
Gaussian Inc., 340 Quinnipiac Street, Building 40, Wallingford, Connecticut 06492, United States.
J Chem Theory Comput. 2022 May 10;18(5):2947-2954. doi: 10.1021/acs.jctc.2c00062. Epub 2022 Apr 6.
Molecules containing late-row elements exhibit large relativistic effects. To account for both relativistic effects and electron correlation in a computationally inexpensive way, we derived a formulation of multiconfiguration pair-density functional theory with the relativistic exact-two-component Hamiltonian (X2C-MC-PDFT). In this new method, relativistic effects are included during variational optimization of a reference wave function by exact-two-component complete active-space self-consistent-field (X2C-CASSCF) theory, followed by an energy evaluation using pair-density functional theory. Benchmark studies of excited-state and ground-state fine-structure splitting of atomic species show that X2C-MC-PDFT can significantly improve the X2C-CASSCF results by introducing additional state-specific electron correlation.
包含重元素的分子表现出较大的相对论效应。为了以计算成本较低的方式同时考虑相对论效应和电子关联，我们推导了一种基于相对论精确二分量哈密顿量的多组态对密度泛函理论（X2C-MC-PDFT）。在这种新方法中，相对论效应通过精确二分量完全活性空间自洽场（X2C-CASSCF）理论在参考波函数的变分优化过程中得以包含，随后使用对密度泛函理论进行能量评估。对原子物种激发态和基态精细结构分裂的基准研究表明，X2C-MC-PDFT通过引入额外的特定态电子关联能够显著改善X2C-CASSCF的结果。
