Energy Spectrum,g Factors,Strain-Induced Level-Splittingsand R-Line Thermal Shift of MgO:V2+

Traditional ligand-field theory has to be improved by taking into accountboth pure electronic contribution and electron-phonon interaction one(including lattice-vibrational relaxation energy). By means of improvedligand-field theory, the R line, t₂^{3 2}T₁ and t₂^{3 2}T₂lines, t₂² (³T₁)e⁴T₂, t₂² (³T₁)e⁴T₁ and t₂e²(⁴A₂)⁴T₁ bands, g factors of t₂^{3 4}A₂ and t₂^{3 2}E, four strain-induced level-splittings and R-line thermal shift ofMgO:V₂₊ have been calculated. The results are in very good agreement with the experimental data. It is found that for MgO:V₂₊, thecontributions due to electron-phonon interaction (EPI) come from thefirst-order term; the contributions from the second-order and higher termsare insignificant. In thermal shift of R line of MgO:V₂₊, thetemperature-dependent contribution due to EPI is dominant. The resultsobtained in this work may be used in theoretical calculations of othereffects of EPI.