The Raman spectrum of gallium metal

Whereas metallic elements with the fcc, hcp and bcc structures have no Raman-active vibrations, solid gallium is found to have one Raman band at 246 cm−1. This band is not observed for molten gallium, and it is attributed to the symmetric stretching vibration of the two Ga2 units in the primitive unit cell. Since solid gallium has Raman-active vibrational modes and has already been reported to exhibit SERS, it should also exhibit plasma resonance enhancement of the Raman scattering by the metal itself, a phenomenon which has not yet been observed experimentally.