Modeling and decoding of fine structure of electron-vibrational 5d – 4f luminescence spectra in LiRF4:Ce3+ (R=Y, Lu) crystals

The 5d-4f luminescence spectra in the LiYF4:Ce3+, LiLuF4:Ce3+ crystals at zero temperature are simulated using a microscopic model of electron-phonon interaction and realistic phonon spectrum of host crystal lattices. Calculations show that three vibrational peaks with the energies 65cm−1, 223cm−1 and 420cm−1 with respect to zero-phonon transition energy dominate in vibrational structure in these spectra. Comparison of simulation results with available experimental data allows to identify zero-phonon lines and vibrational peaks in the measured spectra and thus determine energies of several 4f1 electronic configuration levels: 514, 2221 and 2316cm−1 for LiYF4:Ce3+ and 514, 2188, 2283 and, possibly, 3134cm−1 for LiLuF4:Ce3+ with respect to the ground 4f level energy.