Magnetic circular and linear dichroism in cubic high spin d⁵ complex

Abstract

Magneto-optical parameters useful for the interpretation of magnetic circular dichroism (MCD) and magnetic linear dichroism (MLD) spectra of high spin d⁵ complexes in tetrahedral or octahedral crystalline fields have been calculated. Two possible intensity borrowing mechanisms—one involving spin-orbit (s.o.) interaction of the ground sextet with the excited quartet states and the other involving the s.o. interaction of an excited charge transfer sextet with the excited quartet states—have been considered for electric dipole transitions in T_d symmetry and for magnetic dipole transitions in O_h symmetry. Of the numerous other mechanisms which may induce electric dipole oscillator strength in O_h symmetry complexes, eight (those in involving odd parity T _1u or T _2u states vibronically induced via t _1u or t _2u vibrational modes) have been investigated in detail. In each of these mechanisms, parameters have been calculated for transitions to all individual s.o. components of all excited quartet states. It is shown how the MCD and MLD techniques, if used in combination, may provide specific information on the mechanism of intensity borrowing and on the spectroscopic assignments of individual s.o. components.

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Notes on contributors

M. Vala

On leave from the Department of Chemistry, University of Florida, Gainesville, Florida 32601.