3d-4f Resonant Raman Scattering in Rare-Earth Metal

Publisher Website
Google Scholar
Abstract
We have studied theoretically the soft x‐ray scattering by La metal in the 3d excitation region. The Hamiltonian used includes the terms characterizing a lowering of the 4f level by the 3d hole, Anderson‐type mixing of the 4f orbital with the conduction band, and electron‐photon coupling between the 3d and 4f levels. Using the U‐operator formalism we have obtained the transition probability of Raman scattering as well as fluorescence. Because of the form of interactions considered and approximations made, the mathematical expression of the present theory is in resemblance with that of Nozieres and Abrahams. However, since our main interest is in near resonance excitation, the life time broadening of the 3d hole and the mixing width of the 4f level are explicitly included in the scattering probability, and analytical expressions are derived for the regions near and far from the incident photon energy. As a result of calculations it is shown that the spectra for incident photon energies above the threshold consist of Raman and fluorescence components in contrast to the spectra obtained by incident energies below the threshold which show only a weak Raman component. It is emphasized that the fluorescence component is not an ordinary “absorption followed by luminescence” but the resonance fluorescence induced by the 4f‐conduction electron mixing.

This publication has 0 references indexed in Scilit: