Relativistic Two-Component Multireference Configuration Interaction Method with Tunable Correlation Space

• DOI: 10.1021/acs.jctc.9b01290
• Publication Date: 2020-04-10T17:45:53Z
• Authors: Hang Hu; Andrew J. Jenkins; Hongbin Liu; Joseph M. Kasper; Michael J. Frisch; Xiaosong Li
• Keywords: Multireference configuration interaction; Relativistic quantum chemistry; Electronic correlation; Coupled cluster; Component (thermodynamics); Full configuration interaction; Truncation (statistics); Electron configuration

The multiconfiguration nature of late-row (≥4th) elements and their molecular complexes, combined with significant relativistic effects, present large challenges for the accurate description electronic structure. To address these incorporate both electron correlation we a two-component Kramers-unrestricted multireference configuration interaction method where effects are included variationally at orbital level via use "exact two-component" transformation solution one-electron modified Dirac equation. This is developed within restricted active space framework, allowing flexibility in choice truncation excitation operator, as well promoting efficiency generating book-keeping unique configurations. applied to study fine structure splitting selected p-block d-block further open-shell heavy-element uranium(V) ion.