Effect of reagent ro-vibrational excitation on the electronic ground state dynamics of He + LiH+ → LiHe+ + H reaction.

The effects of ro-vibrational excitation of reagent LiH+ on the He + LiH+(v = 0-4, j = 0 and v = 0, j = 1) → LiHe+(v', j') + H reaction are investigated by employing a time-dependent wave packet propagation approach and quasi-classical trajectory method. A recently developed electronic ground state potential energy surface [Rawat et al., J. Chem. Phys. 161, 124308 (2024)] of the LiHeH+ system is employed for this purpose. Energy resolved total and state-to-state reaction probabilities, integral reaction cross sections, product diatom rotational and vibrational distributions at some selected collision energies, and state-specific rate constants are calculated to elucidate the mechanistic details of the reaction. Reagent vibrational excitations show an intriguing effect on the dynamics, whereas the effect of reagent rotation is mild. Statistical distribution of product vibration suggests an indirect mechanism through the formation of metastable collision complexes on the underlying surface during the course of the reaction.