BROADENING AND SHIFTING OF THE RAMAN Q-BRANCH IN PURE D-2 AND D-2-HE MIXTURES .1. EXPERIMENTAL RESULTS AND COMPARISON WITH THEORY

We report the broadening and shifting of the Raman Q-branch lines in D -2 and D-2-He mixtures, all at 305.2 K. The width and shift of each li ne were extracted by fitting a simple Lorentzian profile to the experi mental data. From a linear fit of the widths and shifts as a function of density we have determined broadening and shifting coefficients wit h an uncertainty of +/-0.5%. None of the existing semiclassical or qua ntal calculations agree with the measurements at this level of accurac y. It is pointed out that the removal of certain approximations in the calculations should bring theory and experiment into closer agreement .