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Natural transition orbitals for complex two‐component excited state calculations
Author(s) -
Kasper Joseph M.,
Li Xiaosong
Publication year - 2020
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.26196
Subject(s) - atomic orbital , molecular orbital , component (thermodynamics) , natural bond orbital , atomic physics , linear combination of atomic orbitals , extension (predicate logic) , physics , electronic structure , chemistry , quantum mechanics , density functional theory , molecule , computer science , programming language , electron
While the natural transition orbital (NTO) method has allowed electronic excitations from time‐dependent Hartree‐Fock and density functional theory to be viewed in a traditional orbital picture, the extension to multicomponent molecular orbitals such as those used in relativistic two‐component methods or generalized Hartree‐Fock (GHF) or generalized Kohn‐Sham (GKS) is less straightforward due to mixing of spin‐components and the inherent inclusion of spin‐flip transitions in time‐dependent GHF/GKS. An extension of single‐component NTOs to the two‐component framework is presented, in addition to a brief discussion of the practical aspects of visualizing two‐component complex orbitals. Unlike the single‐component analog, the method explicitly describes the spin and frequently obtains solutions with several significant orbital pairs. The method is presented using calculations on a mercury atom and a CrO 2 Cl 2 complex.