Crystal field effects on interionic distance in cubic MgO crystal doped with Fe2+ ions

Abstract

The exchange charge model of crystal field was applied to determine the dependence of the crystal field strength 10Dq on interionic distances R between the Fe2+ impurity ion and O2− ligands in cubic MgO:Fe2+. The obtained results were extrapolated by the power law and was shown that 10Dq depends on R as 1/Rn, with n=6.3486. The deviations of these values from the value n=5 (predicted by the simple point charge model of crystal field) is explained by the covalent and exchange effects between impurity ion and ligands; the contribution of these effects into the total crystal field strength was considered separately.The 10Dq functions obtained as a result of our calculations were used for estimations of the electron–vibrational constants, Huang–Rhys parameters, and Jahn–Teller stabilization energy, and compared with available literature data.