This is a followup and extension of a previous study [J. Chem. Phys. 98, 5978 (1993)] that reported decay width calculations for vibrational predissociation (VP) of (HF)2 for total angular momentum J=0 using a hybrid potential energy surface. Detailed quantum dynamics calculations of decay widths in (HF)2 are given in the present study for both J=0 and J=1 and results are shown on both the Quack and Suhm surface and the surface of Bunker et al The lower state of the tunneling doublet in ground vibrational (HF)2 for J=1, K=0 has the - exchange symmetry (tunneling symmetry) in contrast to the + symmetry that the lower state has for J=0. The calculated VP decay widths on two potential energy surfaces (PES) are noticeably different from each other, underscoring the sensitivity of decay widths to details of interaction forces in hydrogen-bonded complexes. The VP dynamics on the PES of Quack and Suhm gives a lifetime differential between v1 and v 2 excitations that is in close agreement with experiments. The calculations on the PES of Bunker et al. do not exhibit enough sensitivity in lifetime between v1 and v2 excitations. In general, theoretical calculations of product rotation distributions are in reasonably good agreement with experimental results. In particular, about 90% of the excess energy in vibrational predissociation of (HF)2 goes into rotations of HF fragments, in good agreement with the recent experimental measurement of Bohac et al.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry