A simple model for f→d transitions of rare-earth ions in crystals

Theoretical simulation and interpretation of f-->d transitions of rare earth ions in crystals are more difficult than for f-->f transitions, because f-->d transitions involve many more energy levels and are further complicated by strong vibronic transitions, so the experimental spectra contain many fewer resolvable peaks. In order to better understand the structure of the spectra, a simple model is developed to take into account the main interactions in the f(N-1)d configuration. This model leads to quantum numbers characterizing the states and the associated transition selection rules. Relative transition intensities can be quantitatively estimated. The model is applied to Eu2+ and Sm3+ ions in crystals. (C) 2003 Published by Elsevier Science (USA).