We have observed resonant Raman scattering from the two longitudinal branches of the Raman-forbidden $F_{1u}$ modes of ${\mathrm{Cu}}_2$O. The agreement between our measured scattering cross section as a function of excitation frequency and a calculated cross section which assumes an intraband Fröhlich electron-phonon interaction is good. This represents a quantitative confirmation of the resonant-Raman-scattering theory proposed by Martin.

• Received 12 July 1972

DOI:https://doi.org/10.1103/PhysRevB.8.1782