Theoretical investigation of local structure distortion and absorption spectra for tetragonal Cr2+ ion in ZnSe:Cr2+ system

By analyzing the zero-field-splitting parameters a and D of Cr2+ (3d4) ion located at tetrahedral site in ZnSe crystal, the local structure distortion and absorption spectra around Cr2+ in ZnSe: Cr2+ system have been calculated on the basis of the complete energy matrix for the d4 configuration within the strong-filed-representation. It is shown that there exists an expansion distortion in the local lattice structure when Cr2+ ion is doped into ZnSe crystal. From our calculations, the distortion parameters 0.20A R  and 3.4 are determined.