Comparison of O_2-O vibrational relaxation and dissociation rate coefficients computed on potential energy surfaces of different fidelity

摘要

The purpose of this study is two-fold: 1) to compare the vibrational relaxation and dissociation rate coefficients for the O_2(~3∑_g~-)+O(~3P) system between the Varandas and Pais potential energy surface (PES), and the Varga et al. 1~1 A′ PES, and 2) to present a new set of state-to-state (STS) vibrational relaxation rate coefficients, state-specific dissociation rate coefficients, and total dissociation rate coefficients using all nine adiabatic ab initio PESs (1~1A′, 2~1A′, 1~1A″, 1~3A′, 2~3A′, 1~3A″, 1~5A′, 2~5A′ and 1~5A") by Varga et al.1 These rate coefficients are calculated from collisional cross-sections obtained using the Quasi-Classical Trajectory (QCT) method for a temperature range T = 2,000 K to T = 12,000 K. Translational-rotational equilibrium is assumed. It is found that using the Varandas and Pais PES leads to vibrational energy transfer rate coefficients which are at most twice higher than those calculated for Varga et al. 1JA′ PES. These differences are not very significant on the logarithmic scale of rates. STS vibrational relaxation rate coefficients for the nine Varga et al. PESs show that the PES that contributes the most towards relaxation varies significantly depending on the vibrational transition considered. This observation indicates that all 9 PESs must be taken into account to present a more complete picture of the full O2-O system. Finally, state-specific and total dissociation rate coefficients, considering cross-sections from all 9 appropriately weighted Varga et al. PESs, are calculated and reported. Contrary to vibrational relaxation, it is observed that dissociation rate coefficients are not sensitive to the 9 Varga et al. PESs.