Quasiclassical state-to-state dynamics of the F + HCl reaction on a ground 12A′ potential energy surface

Abstract

Quasi-classical trajectories have been evaluated to study the state-to-state dynamic for the title reaction on a recent DHTSN PES of the ground 12A′ electronic state [Deskevich et al., J. Chem. Phys. 124 (2006) 224303]. State resolved integral and differential cross sections (DCSs), as well as product rotational polarization, have been obtained for F+HCl (v=0, j=0)→Cl+HF(v′, j′) reaction at Ecol=10.0 and 50.0kcal/mol. Both the vibrational and the rotational distributions are found to be inverted, with the peaks locating at excited final states. At Ecol=10.0kcal/mol, the vibrational resolved DCSs are mainly directed backward and correspond to a simple direct-rebound mechanism. However, for Ecol=50.0kcal/mol, the HF(v′=0) products are preferentially backward-scattered, while the vibrationally excited HF(v′=1, 2, 3) are forward- scattered. These results can be interpreted by increasing of reactive collisions with high-b, which corresponds to a “stripping” dynamics. The P(θr) and P(Φr) distributions and the polarization parameters, a1-{1}, a0{2}, are also obtained to gain insights into the chemical stereodynamics of the title reaction. The HF rotational angular momentum has been found to be both aligned and oriented, and depends sensitively on the product rotational level. Difference in polarization behavior is discussed by means of the reactive mechanism.