부산대학교 도서관

This paper presents two new adiabatic, global potential energy surfaces (PESs) for the two lowest $^3A'$ and $^3A''$ electronic states of the O($^3P$)+H$_2$ system. For each of these states, ab initio electronic energies were calculated for more than 5000 geometries using internally contracted multireference configuration interaction methods. The calculated points were then fitted using the ansatz by Aguado et al. [Comput. Phys. Commun. 108, 259 (1998)] leading to very accurate analytical potentials well adapted to perform reaction dynamics studies. Overall, the topographies of both PESs are in good agreement with the benchmark potentials of Rogers et al., but those presented in this work reproduce better the height and degeneracy of the two states at the saddle point. Moreover, the long range potential in the entrance channel does not require any cutoff. These features makes the new PESs particularly suitable for a comparison of the dynamics on each of them. The new set of PESs were then used to perform quantum mechanics and quasiclassical trajectory calculations to determine integral and differential cross sections, which are compared to the experimental measurements by Garton et al. [J. Chem. Phys., 118, 1585 (2003)].