Effect of Configuration Crossover on the Electronic Raman Scattering by4fMultiplets

The effect of configuration crossover on excited $4f^6\left({}_{}{}^7{}_{}{}^{}F_J^{}{}_{}{}^{}\right)$ levels has been investigated by electronic Raman scattering in ${\mathrm{Sm}}_{1-x}{\mathrm{Y}}_x\mathrm{Se}$ and ${\mathrm{Sm}}_{1-x}{\mathrm{Y}}_x\mathrm{S}$. The multiplet levels are wiped out when they merge with the conduction band, or when interacting with phonons. Polarized Raman-scattering data on ${\mathrm{Sm}}_{1-x}{\mathrm{Y}}_x\mathrm{S}$ for $x>\mathrm{}0.15\mathrm{}$ show that the contribution from $J$-multiplet levels is unobservable and that the peak near 250 ${\mathrm{cm}}^{-1\mathrm{}}$ arises from optic phonons and not from $J=0\mathrm{}\to J=1\mathrm{}$ excitations.