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Ab initio study of molecular g ‐tensors
Author(s) -
Lushington G. H.,
Bündgen P.,
Grein F.
Publication year - 1995
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560550503
Subject(s) - zeeman effect , ab initio , basis set , chemistry , perturbation theory (quantum mechanics) , tensor (intrinsic definition) , atomic physics , physics , electronic correlation , basis (linear algebra) , quantum mechanics , electron , molecule , computational chemistry , mathematics , geometry , magnetic field
The molecular g ‐tensors for the molecules NO 2 , CO 2 − , C 3 H 5 , H 2 CO + , and NF 3 +are calculated at the unrestricted Hartree–Fock ( UHF ) level using the Rayleigh–Schrödinger perturbation approach. All one‐electron terms have been evaluated, including the relativistic mass correction, the one‐electron spin–Zeeman gauge correction, and a second‐order term involving the spin–orbit coupling and the orbital–Zeeman interaction. The relative importance of the first‐order terms is found to be quite substantial. For first‐row molecules, their total contribution is often of the same order of magnitude as of the second‐order contribution, in some instances even larger. A study on the basis‐set dependence of these g ‐tensors has been conducted. At this level, the most important basis‐set criterion is shown to be a satisfactory description of the valence regions. Finally, the gauge dependence of these g ‐tensor calculations has been systematically studied. This dependence seems to be substantially reduced for basis sets which include polarization functions. © 1995 John Wiley & Sons, Inc.