Line broadening studies for isoelectronic divalent and trivalent lanthanides

Temperature-dependent line broadening measurements are reported for transit ions on Sm2+ and Eu3+ (4f(6)) and Eu2+ and Gd3+ (4f(7)). Analysis of the re sults shows that the electron-phonon coupling parameter <(<alpha>)over bar> derived from a fit of the line width data to a two-phonon Raman dephasing process are similar for the divalent and trivalent lanthanides. The low ene rgy of the opposite parity 4f(n-1)5d(1) state for the divalent lanthanides does not result in a significant difference in temperature-dependent line b roadening. This indicates that an extrinsic Raman two-phonon dephasing proc ess involving an opposite parity intermediate state is not responsible for the observed line broadening. (C) 2001 Elsevier Science B.V. All rights res erved.