材料期刊网

By means of both a theory for pressure-induced shifts (PS) of energy spectra and a theory for shifts of energy spectra due to electron-phonon interaction (EPI), the "pure electronic" PS and the PS due to EPI of R-1 line of GSGG:Cr3+ at 70 K have been calculated, respectively. Their physical origins have been revealed. It is found that the admixture of \t(2)(2)(T-3(1))e(4)T(2)) and \t(2)(32) E) base-wavefunctions in the wavefunctions of R-1 level of GSGG: Cr3+ at 70 K is remarkable under the normal pressure, and the degree of the admixture rapidly decreases with increasing pressure. The change of the degree of the admixture with the pressure plays a key role for not only the pure electronic PS of R-1 line but also the PS of R-1 line due to EPI. The detailed calculations and analyses show that the pressure-dependent behaviors of the pure electronic PS of R, line and the PS of R-1 line due to EPI are quite different. It is the combined effect of them that gives rise to the total PS of R, line, which has satisfactorily explained the experimental data (including a reversal of PS of R-1 line). In contributions to PS of R-1 line due to EPI at 70 K, the temperature-independent contribution is much larger than the temperature-dependent contribution. The former results from the interaction between the zero-point vibration of the lattice and localized electronic state.