Degenerate perturbation theory for electronic g tensors: leading-order relativistic effects
2008 (English)In: Journal of Chemical Theory and Computation, ISSN 1549-9618, E-ISSN 1549-9626, Vol. 4, no 11, 1810-1828 p.Article in journal (Refereed) Published
A new approach for the evaluation of the leading-order relativistic corrections to the electronic g tensors of molecules with a doublet ground state is presented. The methodology is based on degenerate perturbation theory and includes all relevant contributions to the g tensor shift up to order theta(alpha(4)) originating from the one-electron part of the Breit-Pauli Hamiltonian-that is, it allows for the treatment of scalar relativistic, spin-orbit, and mixed corrections to the spin and orbital Zeeman effects. This approach has been implemented in the framework of spin-restricted density functional theory and is in the present paper, as a first illustration of the theory, applied to study relativistic effects on electronic g tensors of dihalogen anion radicals X-2(-) (X = F, Cl, Br, I). The results indicate that the spin-orbit interaction is responsible for the large parallel component of the g tensor shift of Br-2(-) and I-2(-), and furthermore that both the leading-order scalar relativistic and spin-orbit corrections are of minor importance for the perpendicular component of the g tensor in these molecules since they effectively cancel each other. In addition to investigating the g tensors of dihalogen anion radicals, we also critically examine the importance of various relativistic corrections to the electronic g tensor of linear molecules with Sigma-type ground states and present a two-state model suitable for an approximate estimation of the g tensor in such molecules.
Place, publisher, year, edition, pages
2008. Vol. 4, no 11, 1810-1828 p.
DENSITY-FUNCTIONAL CALCULATIONS; TRANSITION-METAL-COMPLEXES; PARAMAGNETIC MOLYBDENUM COMPLEXES; SPIN-ORBIT OPERATORS; RESONANCE PARAMETERS; MAGNETIC-PROPERTIES; RESPONSE THEORY; HARTREE-FOCK; G-VALUES; EPR
IdentifiersURN: urn:nbn:se:kth:diva-8428DOI: 10.1021/ct800053fISI: 000260851300002ScopusID: 2-s2.0-58149214184OAI: oai:DiVA.org:kth-8428DiVA: diva2:13743
QC 20100714. Uppdaterad från submitted till published (20100714).2008-05-122008-05-122010-07-14Bibliographically approved