Studies of variation of interionic distances and crystal field effects in ZnS:V2+ and MgO:Cr3+

A detailed microscopic study of the crystal field strength 10Dq for different interionic distances in cubic ZnS:V 2+ and MgO:Cr 3+ single crystals was performed. The exchange charge model of crystal field was used to calculate the 10Dq values for different distances between the impurity ions and ligands. The obtained results were extrapolated by the power laws 10Dq ∼ 1/R n , with n = 4.4208 for ZnS :V 2+ and n = 6.4009 for MgO:Cr 3+ . With these 10Dq(R) dependencies, a number of important physical quantities describing the optical and dynamical properties of impurity centers (such as the constants of the electron-vibrational interaction, Huang-Rhys parameters, Stokes shifts, Jahn-Teller stabilization energies) were estimated and compared with available literature data.