Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction

P. G. Jambrina , Manuel Lara , M. Menéndez , F. J. Aoiz , Jean-Michel Launay (1)

1 IPR - Institut de Physique de Rennes

Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S(1D) + H2 --> SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories (SQCT). The calculations have been carried out on the widely used potential energy surface (PES) by Ho et al. [J. Chem. Phys. 116, 4124 (2002)] as well as on the recent PES developed by Song et al. [J. Phys. Chem. A 113, 9213 (2009)]. The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S(1D).

Mots clés: quantum theory; angular momentum; atom-molecule reactions; hydrogen neutral molecules; potential energy surfaces; molecule-molecule reactions; Quantum theory of reaction cross section; Stochastic theories of rate constants; Potential energy surfaces for chemical reactions; Atom and radical reactions; Transition state theory and statistical theories of rate constants; chain reactions; Rate constants; sulphur; reaction cross sections; reaction rate constants; and activation energies; reaction kinetics theory; Molecular physics; Quantum dynamics; Cold and ultra-cold collisions

Domaines: Chimie-Physique [physics.chem-ph]

P. G. Jambrina, Manuel Lara, M. Menéndez, F. J. Aoiz, Jean-Michel Launay. Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction. Journal of Chemical Physics, 2012, 137 (16), pp.4314. ⟨10.1063/1.4761894⟩. ⟨hal-00856150⟩