ON CALCULATION OF R-LINE THERMAL SHIFT, OF MGO-V2+

The mistakes in Ref. [3] are pointed out. Some important problems are discussed, and the correct ideas, calculations and results are given. The R-line thermal shift of MgO:V2+ at normal pressure is the algebrai c sum of the contribution from electron-phonon interaction and the con tribution from thermal expansion. The latter can be calculated by usin g the thermal expansion coefficient and the pressure-induced shift.