Ab Initio Simulation of Molecular Beam Experiments for the F + H2 → HF + H Reaction

Abstract

The celebrated 1985 molecular beam measurements for the F + H2 reaction of Lee and co-workers, consisting of time-of-flight (TOF) spectra and angular distributions (AD) at several collision energies, have been directly simulated using fully resolved differential cross-sections (DCS) obtained in accurate quantum mechanical (QM) and quasi-classical trajectory (QCT) calculations on the most recent ab initio potential energy surface (PES) by Stark and Werner. The simulations performed using the QM calculations show an unprecedentedly good agreement with the experimental results for all final vibrational states of the HF product. In particular, the height of the peak in the experimental laboratory angular distribution corresponding to HF(v‘=3) forward scattering is quite well reproduced by the simulation using the QM theoretical data at all three experimental collision energies for both para and normal hydrogen. The most important discrepancies between theory and experiment are found in the HF(v‘=3) sideways a...