A typical slow reaction H(2S) + S2(X3Σg-) → SH(X2Π) + S(3P) on a new surface: Quantum dynamics calculations

Quantum dynamics calculations for the title reaction H(S-2) + S-2(X-3 Sigma(-)(g)) -> SH(X-2 Pi) + S(P-3) are performed by using a globally accurate double many-body expansion potential energy surface [J. Phys. Chem. A 115 5274 ( 2011)]. The Chebyshev real wave packet propagation method is employed to obtain the dynamical information, such as reaction probability, initial state-specified integral cross section, and thermal rate constant. It is found not only that there is a reaction threshold near 0.7 eV in both reaction probabilities and integral cross section curves, but also that both the probability and cross section increase firstly and then decrease as the collision energy increases. The existence of the resonance structure in both the probability and cross section curves is ascribed to the deep potential well. The calculation of the rate constant reveals that the reaction occurring on the potential energy surface of the ground-state HS2 is slow to take place.