Depolarized-light-scattering spectrum of normal gaseous hydrogen at low density and a temperature of 297 K

We have measured the depolarized-light-scattering spectrum of normal ${\mathrm{H}}_2$ at T=297 K as a function of the density between ρ=17.8 and ρ=129 amagat up to the frequency ν=865 ${\mathrm{cm}}^{\mathrm{-}1}$. The spectrum between 6 and 240 ${\mathrm{cm}}^{\mathrm{-}1}$ is dominated by the ‘‘translational’’ depolarized interaction-induced part from which the two-body spectrum and the three-body correlation spectrum have been extracted and compared with the theoretical predictions obtained with the dipole-induced-dipole polarizability model and an isotropic pair-interaction potential. We have also measured the spectrum in the wings of the rotational transition S(0),S(1),S(2) between 240 and 865 ${\mathrm{cm}}^{\mathrm{-}1}$ and demonstrated, for the first time, its quadratic behavior versus density in the above-mentioned density range. This portion of the spectrum is attributed mostly to pure collisional broadening.