ISSN:
0040-5744
Keywords:
Key words: Electronic g-tensor
;
Zeeman effect
;
Gauge invariance
;
Hartree
;
Fock wavefunctions
;
Magnetic properties
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract. The electronic g-tensors for NO2, CO+ and H2O+ are calculated at the restricted open-shell Hartree–Fock (ROHF) level using the Rayleigh–Schrödinger perturbation approach. All known first- and second-order contributions have been evaluated, including the relativistic mass correction, one- and two-electron spin Zeeman gauge correction terms, and one- and two-electron second-order terms. Substantial code development has been necessary, including an integral routine for computing the two-electron spin-Zeeman gauge correction term. Calculations have been done using triple zeta and quadruple zeta basis sets with additional polarization and semi-diffuse functions. Effective gauge invariance is obtained by placing the gauge origin at the molecule’s electronic charge centroid. Excited state energies in the sum-over-states expansion are expressed using determinantal energies, thus avoiding the non-uniqueness of ROHF eigenvalues. Our results successfully reproduce trends in gas phase g-shifts (Δg=g−g e). However, discrepancies between our calculated g-shifts and experimental ones, sometimes on the order of 50%, point to the need for a correlated treatment.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01127505
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