Electronic structure of the F center in SrO

Absorption and emission states of the F center in SrO have been calculated using a theoretical model which emphasizes the importance of (i) electronic structure on the ions neighboring the defect, (ii) electronic and ionic polarization of the lattice, and (iii) lattice distortion and its effects on the energy levels and wave functions of the defect. The electron-lattice interaction for A1g, Eg, and T2g displacements of the nearest-neighbor ions has been calculated and used to interpret the absorption and luminescence bands of the F center. The calculated energy-level scheme as a function of lattice relaxation predicts luminescence bands corresponding to the ¹T₁ᵤ→¹A1g transition at 1.5 eV and to the ³T₁ᵤ→¹A1g transition at 0.56 eV. It also suggests the possibility of observing the excited-state absorption for the ³T₁ᵤ→¹A1g transition at about 1.9 eV. Calculations of the Jahn-Teller coupling constants indicate that both the ¹T₁ᵤ unrelaxed excited absorption and the ³T₁ᵤ relaxed emission states are strongly coupled to the T2g vibrational modes.