Dynamic Aspects of Light Scattering by Gases [and Discussion]

Light scattering experiments involving the rotational Raman and depolarized Rayleigh spectra of H$_{2}$, D$_{2}$ and HD have been performed. From the collisional broadening and collisional frequency shift of these lines, it is possible to infer much about the dynamics of molecular collisional processes. In particular, the elastic and inelastic contributions to the linewidths can be separated by studying their temperature dependence over a range 25-300 K. Moreover, measuring the linewidths as a function of ortho-para composition permits a study of the rather strong influence of resonance collisions. The results will be compared with scattering theory calculations based on the distorted wave Born approximation.