INTERACTIONS WITHIN EXCHANGE COUPLED TRIADS OF TRANSITION METAL IONS

Abstract

The purpose of this work is to describe the energy structure of asymmetric triads (d3-d3-d2 and d2-d2-d3) which can be used in interpreting the spectra of mixed valence transition metal ions. A many body technique has been developed to understand the structure of these two triads. The wave functions for crystal, and the difference between it and full Hamiltonian is then treated by perturbation theory, taken to second order. Ab-initio calculations have been performed using the second quantization formulation to calculate the exchange interactions within 3T1, 3T1, 4A2) and 4A2, 4A2, 3T1) ground manifolds. This leads to exchange matrices that describe the energy structure of triads. The energy levels associated with exchange coupled asymmetric triads have been studied and allowed electric dipole transitions have been predicted. The splitting of manifolds under the combined effects of exchange, trigonal field and spin-orbit interactions have been described