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 $\mathrm{J\; \to \; J}$ of the Q branch of Raman bands. We report here on experimental results obtained on the transitions $\text{J=0, 1, ···, 4}$ 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 $\mathrm{O–O}$ 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.