Raman Q-branch line shapes as a test of a H2–Ar intermolecular potential.

The Le Roy–Hutson intermolecular potential for H2–Ar, which was derived from analysis of spectral data for the van der Waals complex and also shown to predict gas kinetic transport cross sections in good accord with experimental values, was subsequently found to provide rather poor predictions (small by nearly a factor of 2) for vibrational Q-branch Raman line shift cross sections. More recently, an ab initio intermolecular potential for this system has been calculated and scaled to agree with the earlier one in the region of the minimum where the latter is expected to be accurate [D. W. Schwenke et al., J. Chem. Phys. 98, 4738 (1993)]. We show here that this potential predicts line shifts in much better accord with experiment (about 10% large), but its predictions for linewidths are significantly less satisfactory. [ABSTRACT FROM AUTHOR]