A. Ellens et al., THE VARIATION OF THE ELECTRON-PHONON COUPLING STRENGTH THROUGH THE TRIVALENT LANTHANIDE ION SERIES, Journal of luminescence, 66-7(1-6), 1995, pp. 240-243
The electron-phonon coupling for trivalent lanthanides is studied by t
emperature-dependent linewidth measurements. The results indicate that
the coupling is strong at the beginning and at the end of the lanthan
ide series and weak in the middle.