SPECTRAL-LINE-BROADENING STUDY OF THE TRIVALENT LANTHANIDE-ION SERIES.1. LINE BROADENING AS A PROBE OF THE ELECTRON-PHONON COUPLING STRENGTH

Line broadening is evaluated as a method to probe an electron-phonon c oupling strength of lanthanide ions. Various problems which complicate the analysis of line broadening, like a contribution of different rel axation processes and the difference in behavior for different transit ions in the same system are discussed, using LiYF4:Eu3+ and LiYF4:Pr3 as examples. The results show that the electron-phonon coupling param eter <(alpha)over bar>, derived from a fit to the Raman two-phonon pro cess for different transitions, provides a good estimate of an electro n-phonon coupling strength. In a second paper this line broadening met hod is used to probe the variation of the electron-phonon coupling str ength through the trivalent lanthanide ion series.