Density evolution of the double rotational transition in condensed parahydrogen

The Raman intensity of the forbidden S0(0)+S0(0) transition has been measured both in the liquid and in the solid phase. The detailed theory of the integrated intensity of such forbidden spectra is presented which involves the pair correlation function of the system together with the anisotropic components of the intermolecular potential and certain components of the collision induced polarizability. The experimental results are compared with the numerical evaluations obtained with models for the intermolecular potential and collision induced polarizability that are taken from literature.