Raman Q and S line broadening and shifting coefficients: some commonly used assumptions revisited

We use quantum calculations to study two features in the behaviour of Raman S(j) and Q(j) broadening and shifting coefficients of the H2–He system: the influence of the centrifugal distortion of the potential, and the j and E dependences of the dephasing contribution to the Q(j) broadening coefficients. We stress that certain approximations used in modelling experimental data must be reconsidered, and we examine how to properly account for these effects within a semiclassical model.