Title: A theoretical study on the HSO2 molecular system

Author: M. Y. Ballester.

Departamento de Quimica, Universidade de Coimbra, Portugal.

Abstract: A global potential energy surface (PES) for the ground electronic state of title system is here reported and characterized. Double

many-body expansion (DMBE) method was used to construct such a six dimensional function. Ab initio calculation on the title system at

Full Valence Complete Active Space Self Consistent Field level using aug-cc-XTZ(X=2,3) basis sets were carried and used to calibrate the

four body energy terms. The function properly describes all possible configuration of the tetratomic system. By means of quasi-classical

trajectories method and the obtained PES, the reactions S+HO2--> OH+SO, OH+SO--> H+SO2 and its reverse, has been studied.

Reactive cross section and rate coefficients are here reported and compared with data available in literature. Details on reaction mechanisms

are also presented.