Temperature dependence of the Raman spectra of liquid parahydrogen.

Vibrational and rotational spectra of liquid para-H2 at temperature T=14–26 K and of solid at T=6–13 K have been obtained using coherent anti-Stokes Raman scattering technique. The vibrational frequency in the liquid increases with temperature by about 2 cm-1 and the shift scales with the square of the sample’s density. An extrapolation of the vibrational frequency in the metastable para-H2 liquid below the freezing point is discussed. The results indicate that the vibron hopping between the molecules is active in the liquid, similar to that previously found in the solid. [ABSTRACT FROM AUTHOR]