title: Comparative calculation of EPR spectral parameters in [Mo(V)OX4]-, [Mo(V)OX5]2-, and [Mo(V)OX4(H2O)]- complexes.
abstract: The EPR spectral parameters, i.e. g-tensors and molybdenum hyperfine couplings, for several d(1) systems of the general formula [Mo(V)EX(4)](n-), [Mo(V)OX(5)](2-), and [Mo(V)OX(4)(H(2)O)](-) (E = O, N; X = F, Cl, Br; n = 1 or 2) were calculated using Density Functional Theory. The influence of basis sets, their contraction scheme, the type of exchange-correlation functional, the amount of Hartree-Fock exchange, molecular geometry, and relativistic effects on the calculated EPR spectra parameters have been discussed. The g-tensors and molybdenum hyperfine coupling parameters were calculated using a relativistic Hamiltonian coupled with several LDA, GGA, and 'hybrid' exchange-correlation functionals and uncontracted full-electron DGauss DZVP basis sets. The calculated EPR parameters are found to be sensitive to the Mo=E distance and E=Mo-Cl angle, and thus the choice of starting molecular geometry should be considered as an important factor in predicting the g-tensors and hyperfine coupling constants in oxo-molybdenum compounds. In the present case, the GGA exchange-correlation functionals provide a better agreement between the theory and the experiment.
authors.affiliation: Department of Chemistry and Biochemistry, University of Minnesota Duluth, Duluth, MN 55812, USA.
authors.forename: Ryan G
authors.initials: RG
authors.lastname: Hadt
authors.forename: Victor N
authors.initials: VN
authors.lastname: Nemykin
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Olsen
authors.forename: Partha
authors.initials: P
authors.lastname: Basu
mesh_terms: D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D008982:Molybdenum / Q000737:chemistry*
chemical_list: D008982:Molybdenum