THEORETICAL REPRODUCTION OF THE ELECTRONIC RAMAN-SPECTRA OF CERIUM IONS .3. INTENSITIES AND ASYMMETRY FEATURES

The intensities and asymmetry features of Raman spectra of Ce+3 ion in LuPO4 are analyzed. The discussion is based on the numerical results of ab initio calculations performed within the third-order crystal-field approach introduced in the previous papers of the present series. In this approach the scattering amplitude is determined by second- and third-order effective operators for which the standard selection rules are satisfied and, in addition, by operators that are beyond the standard scheme. The latter terms change the traditional picture of electronic Raman scattering. The complete analysis of all possible effective operators originating from intrashell and intershell interactions via the crystal-field potential allows one to better understand the nature of the electronic Raman scattering. It also sheds some light onto the explanation of the reason for the difficulties found in the semiempirical approaches reported in the literature. The investigations reported in this series of papers are completed by a good agreement between theoretical and experimental values of the ratio of differential scattering cross section.