Depolarized scattering from p a r a and normal hydrogen

Experimental data on depolarized light scattering for the Rayleigh and vibrational Raman bands of hydrogen at 123 K are presented for densities between 20 and 130 amagat. The para-hydrogen (∼J=0) depolarized spectra are found quasiexponential contrary to the thermal equilibrium hydrogen Rayleigh spectrum. In this last spectrum the low frequencies part (Δν<40 cm−1) shows a contribution from the permanent anisotropy of the ortho molecules (J=1). The integrated depolarization ratios are measured for the Rayleigh and the vibrational Raman bands of para-hydrogen. A discussion of the results shows that the first order dipole induced dipole model fails to give an accurate description of all observed intensities.