Complementarity between Quantum and Classical Mechanics in Chemical Modeling. The H + HeH+ -> H2+ + He Reaction: A Rigourous Test for Reaction Dynamics Methods

In this work we present a dynamical study of the H + HeH+ -> H+2+ He reaction in a collision energy range from 0.1 meV to 10 eV, suitable to be used in applicative models. The paper extends and complements a recent work [Phys. Chem. Chem. Phys., 2014, 16, 1162] devoted to the characterization of the reactivity from the ultra- cold regime up to the three-body dissociation breakup. In particular, the accuracy of the quasi-classical trajectory method below the three-body dissociation threshold has been assessed by a detailed comparison with previous calculations performed with different reaction dynamics methods, while the reliability of the results in the high energy range has been checked by a direct comparison with the available experimental data. Integral cross sections for several HeH+ roto-vibrational states have been analyzed and used to understand the extent of quantum effects in the reaction dynamics. By using quasi- classical trajectory method and quantum mechanical close coupling data, respectively in the high and low collision energy ranges, we obtain highly accurate thermal rate costants until 15,000 K including all (178) the roto-vibrational bound and quasi-bound states of HeH+. The role of the collision induced dissociation is also discussed and explicitly calculated for the ground roto-vibrational state of HeH+.