Raman scattering of the C-C vibration with ${\mathit{E}}_{2\mathit{g}2}$ symmetry in stage-2 C/Rb has been studied with different incident photon energies. Resonant enhancement occurs for laser energies in the blue region, close to the threshold for the valence- to conduction-band electronic transition ${\mathrm{\Omega }}_{\mathit{T}}$. The results were fitted with a two-band resonance enhancement model and the fitting procedure yields ${\mathrm{\Omega }}_{\mathit{T}}$=2.6±0.15 eV, with a broadening of 0.13 eV. In the red spectral region, the Raman line exhibits a Fano-type distortion, indicating an interaction between the discrete one-phonon excited state, and a continuum which is attributed to electronic excitations.

• Received 5 March 1990

DOI:https://doi.org/10.1103/PhysRevB.43.1773