Global analytical potential energy surfaces for H O 2 ( X ̃ A ″ 2 ) basedon high-level ab initio calculations

• Published in: The Journal of chemical physics 2007-02, Vol.126 (7), p.074315-074315-8
• Main Authors: Xie, Daiqian, Xu, Chuanxiu, Ho, Tak-San, Rabitz, Herschel, Lendvay, György, Lin, Shi Ying, Guo, Hua
• Format: Article
• ISSN: 0021-9606; 1089-7690
• DOI: 10.1063/1.2446994

Two global analytical potential energy surfaces for the H O 2 ( X ̃ A ″ 2 ) system have been developed by fitting ∼ 15 000 ab initio points at the icMRCI + Q ∕ aug - cc - pVQZ level of theory, using the reproducing kernel Hilbert space method. One analytical potential is designed to give a very accurate representation of the low energy range that determines the vibrational spectrum, while the other attempts to provide a fast and uniformly accurate potential function for reaction dynamics. The quality of the fitted potential functions is confirmed by good agreement of the ( J = 0 ) H O 2 vibrational spectrum and ( J = 0 ) quantum reaction probability for the H + O 2 ( j i = 0 , ν i = 0 ) reaction with those obtained using the spline fitted potential. Quasiclassical trajectory calculations carried out on the new potential energy surface provided the reaction probability with a zero impact parameter ( b = 0 ) , which is in reasonably good agreement with the J = 0 quantum results.