The R line and U band optical spectra of substitutional Cr3+ and V2+ in MgO have been calculated at normal pressure, and their pressure-induced shifts have been determined by use of the semi-empirical crystal-field (CF) theory and the first-principles SCF embedded-cluster discrete variational (DV-X alpha) method. Local lattice relaxations around the impurity ion have been determined to high precision by matching theoretical to experimental spectra. The excellent agreement between crystal-field, SCF, and experimental results verifies the proposed dependence of CF parameters upon pressure, and shows that the SCF approach can be used with confidence in cases where insufficient data are available for semiempirical fitting.
部门归属
northwestern univ,dept phys & astron,evanston,il 60208. chengdu univ sci & technol,dept phys,chengdu 610065,peoples r china. acad sinica,int ctr mat phys,shenyang 110015,peoples r china.
修改评论