J Dependence of the depolarization ratio of the rotational components of the Q branch of the H2 and D2 Raman band

The theory on rotational structure of Raman bands predicts-apart from the (2J+1) magnetic degeneracy-an additional J dependence of anisotropic scattering. This implies a J dependence of the depolarization ratio, when measured for the separated rotational components J → J of the Q branch of Raman bands. We report here on experimental results obtained on the transitions J=0, 1, ···, 4 of the Q branch of H2 and D2, which are in full agreement with theory. In particular we demonstrate the completely isotropic character of the O–O transition. Our experimental value for the depolarization ratio of the total vibrational Raman band of H2 agrees well with the one obtained recently by ab initio calculations.