Raman Scattering from Condensed Phases ofHe3andHe4

Abstract

Inelastic light scattering with frequency shifts from 10 to 150 ${\mathrm{cm}}^{-1\mathrm{}}$ has been measured in liquid and solid ${\mathrm{He}}^3$ and ${\mathrm{He}}^4$ under pressures up to 150 atm. In the hcp solids a transverse optic phonon was observed and resolved. In addition a broad peak was observed which is remarkably similar in both liquids and solids. In the solid this peak is interpreted as scattering from two or more damped, coupled phonons. Scattering intensities and spectral forms are compared with recent theoretical calculations.