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 Hamiltonian 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 linear Zeeman and the second-and fourth-order zero-field spin Hamiltonian parameters. Symmetry restraints can easily be applied but application to non-symmetric molecules with determination of all 20 spin Hamiltonian parameters does not present particular difficulties. The model is based on a direct comparison of the spin Hamiltonian energies with the ligand held energies including spin-orbit coupling and Zeeman interaction 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 Science S.A. All rights reserved.