Predissociation of HD–Ar van der Waals molecules by internal rotation

Accurate close-coupling calculations of level energies and widths of predissociating levels of HD–Ar have been carried out using the Le Roy–Carley BC3 potential for H2–Ar. The calculated widths agree well with the experimental data of McKellar. The principal product from predissociation of HD(v=1, j=2)–Ar is HD in its v=1, j=1 state. This channel is symmetry forbidden for H2(1, 2)–Ar, and its presence accounts for the much larger spectroscopic linewidths found for HD–Ar.