Abstract

Spectra of ions substituted at centrosymmetric sites in crystals ought to be the easiest cases to analyze because they have the smallest number of crystal field parameters. This high symmetry should also be of advantage if one wants to understand the forces resulting from electronic excitations which cause the Jahn-Teller effect and lattice mode excitations. For intraconfigurational transitions d→d, f→f and for other cases in which parity is the same for ground and excited state, such as d→s, the spectra observed are disappointingly complicated because odd parity vibronic activity is a necessary accompaniment of one-photon transitions. In the few cases where magnetic dipole transitions can be observed, they are limited to the electronic origins and even parity vibronic structure is usually obscured by odd parity structure.

© 1986 Optical Society of America