Spectroscopy and calculations for 4f(N)-> 4f(N)-15d transitions of lanthanide ions in LiYF4

Excitation spectra of transitions between the 4f(N) and 4f(N-1)5d configura tions of Ce3+, Pr3+, and Nd3+ in LiYF4 have been measured using UV and VUV synchrotron radiation. Both zero-phonon lines and vibronic bands are observ ed. The energy levels and transitions intensities an reproduced by a theore tical model that extends established models for the 4f(N) configuration by including crystal-field and spin-orbit interactions for the 5d electron and the Coulomb interaction between the 4f and 5d electrons.