ANGULAR OVERLAP CALCULATIONS OF THE SPIN-HAMILTONIAN PARAMETERS OF TRANSITION-METAL IONS IN LOW-SYMMETRY ENVIRONMENTS - HIGH-SPIN IRON(II),IRON(III) AND MANGANESE(III)

A non-perturbative method is presented for the calculation of spin Ham iltonian parameters of d(n) ions, 1 less than or equal to n less than or equal to 9. In its present form, it allows the calculation of the l inear Zeeman and the second-and fourth-order zero-field spin Hamiltoni an parameters. Symmetry restraints can easily be applied but applicati on to non-symmetric molecules with determination of all 20 spin Hamilt onian parameters does not present particular difficulties. The model i s based on a direct comparison of the spin Hamiltonian energies with t he ligand held energies including spin-orbit coupling and Zeeman inter action of all-order perturbation. The model is applied to compute the spectromagnetic parameters of high spin iron(III), high spin iron(II) and high spin manganese(III) model chromophores. (C) 1998 Elsevier Sci ence S.A. All rights reserved.