A quantum wave packet dynamical study of the electronic and spin−orbit coupling effects on the resonances in Cl(²P) + H₂ scattering

Abstract

Dynamical resonances in Cl(²P) + H₂ scattering are investigated with the aid of a time-dependent wave packet approach using the Capecchi−Werner coupled ab initio potential energy surfaces [Phys. Chem. Chem. Phys. 2004, 6, 4975]. The resonances arising from the prereactive van der Waals well (∼0.5 kcal/mol) and the transition-state (TS) region of the ²Σ_1/2 ground spin−orbit (SO) state of the Cl(²P) + H₂ system are calculated and assigned by computing their eigenfunctions and lifetimes. The excitation of even quanta along the bending coordinate of the resonances is observed. The resonances exhibit an extended van der Waals progression, which can be attributed to the dissociative states of ClH₂. Excitation of H₂ vibration is also identified in the high-energy resonances. The effect of the excited ²P_1/2 SO state of Cl on these resonances is examined by considering the electronic and SO coupling in the dynamical simulations. While the electronic coupling has only a minor impact on the resonance structures, the SO coupling has significant effect on them. The nonadiabatic effect due to the SO coupling is stronger, and as a result, the spectrum becomes broad and diffuse particularly at high energies. We also report the photodetachment spectrum of ClD₂^- and compare the theoretical findings with the available experimental results.