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Calculation of EPR g Tensors for Transition‐Metal Complexes Based on Multiconfigurational Perturbation Theory (CASPT2)
Author(s) -
Vancoillie Steven,
Malmqvist PerÅke,
Pierloot Kristine
Publication year - 2007
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200700128
Subject(s) - zeeman effect , chemistry , degenerate energy levels , electron paramagnetic resonance , perturbation theory (quantum mechanics) , quantum chemistry , molecule , transition metal , computational chemistry , perturbation (astronomy) , atomic physics , crystallography , quantum mechanics , physics , magnetic field , supramolecular chemistry , biochemistry , organic chemistry , catalysis
The computation of the electronic g tensor by two multireference methods is presented and applied to a selection of molecules including CN, BO, AlO, GaO, InO, ZnH, ZnF, O 2 , H 2 O + , O 3 − , and H 2 CO + (group A) as well as TiF 3 , CuCl 4 2− , Cu(NH 3 ) 4 2+ , and a series of d 1 ‐MOX 4 n − compounds, with M=V, Cr, Mo, Tc, W, Re and X=F, Cl, Br (group B). Two approaches are considered, namely, one in which spin–orbit coupling and the Zeeman effect are included using second‐order perturbation theory and another one in which the Zeeman effect is added through first‐order degenerate perturbation theory within the ground‐state Kramers doublet. The two methods have been implemented into the MOLCAS quantum chemistry software package. The results obtained for the molecules in group A are in good agreement with experiment and with previously reported calculated g values. The results for the molecules in group B vary. While the g values for the d 1 systems are superior to previous theoretical results, those obtained for the d 9 systems are too large compared to the experimental values.