The many faces of vibrational energy relaxation in N2(v) + O(1D) collisions: Dynamics on 1Π and 1Δ potential energy surfaces.

Abstract

Complete datasets of rate coefficients for the vibrational quenching of molecular nitrogen by collision with electronically excited atomic oxygen O(1D) over a wide temperature range are calculated for the first time. Such data are important ingredients in the modeling of non-local thermal equilibrium conditions that characterize the atmosphere, media of astronomical interest, and cold and hot plasmas, where O(1D), also formed when O2 molecules break, represents a significant fraction of the gas mixture. To this end, we developed analytical potential energy surfaces (PESs) for the 1Π and 1Δ electronic states of the N2-O(1D) system to accurately describe the interaction in the long, medium, and first repulsive range of intermolecular distances, the most effective regions in inelastic collisions under a variety of conditions of interest. The derived PESs are used to calculate the vibration-to-translation (V-T) and vibration-to-electronic (V-E) energy transfer rates by mixed quantum-classical dynamics and by the Landau-Zener formulation, respectively. In addition, the datasets are extended to cover the entire N2 vibrational ladder by using the Gaussian process regression. The results show that at low temperatures, where V-E relaxation dominates, N2 vibrational quenching by O(1D) collisions is faster than by O(3P) collisions.