Vibrational dephasing in H2and HD dissolved in liquid and hypercritical argon

Abstract
Lineshape data have been obtained for the isotropic Raman spectra of HD and para H2 diluted in liquid and hypercritical argon. The observed profiles near 2ρc are interpreted in terms of pure vibrational dephasing and fast modulation process. In the critical region an inhomogeneous broadening is observed; it is superimposed in the HD case, on a rotational contribution. A detailed analysis of the Q spectra obtained for the normal H2-argon system along the critical isochore provides evidence for the role of density fluctuations near the liquid-gas critical point.