Explanations of the absorption spectra and their pressure coefficients forZnSe : Ni2+ crystal

The optical absorption spectra and their pressure coefficients for ZnSe:Ni2 + crystal have been calculated by diagonalizing the energy matrices based o n a modified crystal-field theory. In the matrices, the covalency parameter s N-t, N-e and the spin-orbit coupling coefficients zeta (tt), zeta (te) ar e obtained from a cluster approach including only one adjustable parameter. The calculated optical spectra are in agreement with the observed values. The calculated pressure cocmcients for T-2-T-3(2)(F-3) and T-2-T-1(2)((1)G) bands under low and high pressures are also consistent with the observed v alues. The differences of pressure coefficients under low and high pressure s for T-2-(3)A(2)(3F) and T-2-T-3(1)(P-3) bands are analyzed and discussed. (C) 2001 Elsevier Science B.V. All rights reserved.