Crystal Field Analysis, Electron-phonon Coupling and Spectral Band Shape Modeling in MgO:Cr3+

A crystal field analysis of the energy level structure of Cr3+ in MgO crystal is performed, using the exchange charge model of the crystal field theory. The crystal field parameters acting on the optical electrons of Cr3+ are calculated from the crystal structure data; good agreement between the calculated and observed energy levels of Cr3+ in the title host is demonstrated. The Stokes shift S= 5.9 and the energy of the phonons effectively interacting with the impurity center h̄ω = 405 cm−1 are derived from the experimental spectra of absorption and emission. The obtained values of S and h̄ω were used for the computer modeling of the Cr3+ T2g → A2g emission and A2g → T2g absorption bands. From this modeling, the zero-phonon energy for the considered transitions was estimated to be 14,000 cm−1.