A new ab initio potential-energy surface of HO 2(X 2 A″) and quantum studies of HO 2 vibrational spectrum and rate constants for the H+O 22↔O+OH reactions

Abstract

A new global potential-energy surface for the ground electronic state of H O2 (X2 A″) has been developed by three-dimensional cubic spline interpolation of more than 15 000 ab initio points, which were calculated at the multireference configuration-interaction level with Davidson correction using the augmented correlation-consistent polarized valence quadruple zeta basis set. Low-lying vibrational states were obtained in this new potential using the Lanczos method and assigned. The calculated vibrational frequencies are in much better agreement with the available experimental band origins than those obtained from a previous potential. In addition, rate constants for the H+ O2 ↔O+OH reactions were obtained using a wave-packet-based statistical model. Reasonably good agreement with experimental data was obtained. These results demonstrate the accuracy of the potential. © 2005 American Institute of Physics.