Electron paramagnetic resonance of Co2+ compounds (abstract)

Abstract

In cubic crystal field, the ground state of d7 configuration is 4T1 which is an orbital degenerate state. Even though it is in low symmetric crystal field, the orbital degeneracy of 4T1 is not completely quenched. So it makes it difficult to study its ground-state properties, such as the electron spin resonance g factors and the splitting of ground state. Usually, the method of ‘‘T-P’’ equivalence which is not convenient to investigate the physical processes was used in the previous works. In the present work, the formulae of d-d transition, the splitting of ground state, and the electron paramagnetic resonance parameter, which relate these quantities to the crystal structure as the d orbit of Co2+ is employed, are derived. The present theory shows that g∥>g⊥ and g∥<g⊥ are due to the different distortion of ligands along C3 axis. On the basis of ab initio, the formulae obtained are applied to deal with the magnetic properties of some Co2+ compounds. The agreement of theory with the experiment shows that the present theory is reasonable.