Improved Ligand-Field Theoretical Calculations of R-Line Thermal Broadenings of NIgO：Cr^3＋ and MgO：V^2＋

With the values of parameters obtained from improved ligand-field theory, by taking into account all the irreducible representations and their components in EPI as well as all the levels and the admixtures of basic wavefunctions within d^3 electronic configuration, the R-line thermal broadenings （TB） of both MgO：Cr^3＋ and MgO：V^2＋ have microscopic-theoretically been calculated, The results are in very good agreement with the experimental data. It is found that the R-line TB of MgO：Cr^3＋ or MgO：V^2＋ comes from the first-order term of EPI. The elastic Raman scattering of acoustic phonons plays a dominant role in R-line TB of MgO：Cr^3＋ or MgO：V^2＋.