Theoretical determination of rate constants for vibrational relaxation and reaction of OH(XΠ2,v=1) with O(P3) atoms

Abstract

Collisions of the vibrationally excited OH(v = 1) molecule with atomic oxygen are investigated theoretically using a coupled-states, statistical capture (CS-ST) model. Vibrational relaxation can occur by inelastic scattering, and the vibrationally excited molecule can also be removed by reaction to form O(2) in both the ground (X (3)Sigma(g)(-)) and first excited (a (1)Delta(g)) state. In the former case, reaction occurs on the lowest potential energy surface of (2)A(") symmetry, and, in the latter case, by reaction on the lowest potential energy surface of (2)A(') symmetry. We report new ab initio potential energy surfaces for both these states in the product and reactant regions necessary for application of the coupled-states, statistical method. Comparison with exact, reactive scattering calculations within the J-shifting approximation indicate that the CS-ST rate constants for removal of OH(v = 1) can be expected to be reasonably accurate. Our calculated rate constants at 300 K agree well with the experimental results of Khachatrian and Dagdigian [Chem. Phys. Lett. 415, 1 (2005)]. Reaction to yield O(2) (X (3)Sigma(g)(-)) is the dominant removal pathway. At subthermal temperatures, the rate constants for the various vibrational quenching processes all increase down to T approximately = 60 K and then decrease at lower temperature.

Accurate time dependent wave packet calculations for the N + OH reaction

“…This behavior, which is characteristic of barrierless exothermic reactions, is similar, among others, to the radical-radical OH + O reaction, as recently reported by some groups. 38,39 The agreement between the WP and QCT excitation functions is quite good for the whole range of collision energies, except for low energies, below 0.05 eV, where the WP results are considerably larger than the QCT ones. The reason of the faster increase of the WP cross section is the resonances appearing near the threshold.…”

Time-dependent quantum wave packet dynamics of the C + OH reaction on the excited electronic state

“…They exhibit sharp and dense resonance structures in the observed initial state selected reaction probabilities. 30,[33][34][35][36][37] The initial state-selected integral cross sections exhibit a maximum value at the onset and the reaction rate decreases with increasing temperature beyond ∼50 K. 30,[33][34][35][36][37][38][39][40][41] …”

Transport Properties for Systems with Deep Potential Wells: H + O2

“…52 Further details about the PES calculation can be found in the original article. 50 We present in panel a of Figure 1 53,54 An atom centered avqz atomic-orbital basis was used, 55 with the addition of a set of bond functions located midway between the atom and the molecule. 56 A counterpoise correction was applied at all geometries to correct for basis set superposition error.…”