Influence of Covalency on the Mn4+ 2Eg→4A2gEmission Energy in Crystals

In this paper we review the spectroscopic properties of the Mn 4+ ion (3d 3 electronic configuration) and establish a relationship between the energy of the 2 E g → 4 A 2g emission transition and the covalence of the "Mn 4+ -ligand" bonding. A new parameter (where ( B , C ( B 0 , C 0 ) are the Racah parameters of the Mn 4+ ions in a crystal (free state), respectively) was recently introduced that allows for establishing a linear relationship between β 1 and the energy of the 2 E g level. This makes it possible to understand the large variation in the energy of the 2 E g → 4 A 2g emission transition that is frequently encountered in the spectroscopy of the Mn 4+ ions in solids.