Vibrational relaxation in liquid hydrogen and deuterium bromide—The influence of self and distinct correlation functions on the isotropic and anisotropic Raman line shape

Abstract

Both, the isotropic and anisotropic Raman line shapes of orthobaric liquid hydrogen and deuterium bromide are measured at 295 K and close to the triple point (185 K). Concentration dependent studies in HBr/DBr mixtures allow an experimental separation of the resonant transfer mechanism from other line broadening mechanisms. It is found that the anisotropic spectra are nearly unaffected by isotopic dilution, whereas the isotropic ones show a blue shift and a narrowing with increasing isotopic dilution. The overall contribution of the transfer mechansim to the line broadening becomes most pronounced at the lower temperature. The results are discussed in terms of a recent Raman line shape theory of Bratos and Tarjus.