Implications of the O + OH reaction in hydroxyl nightglow modeling

Abstract

Abstract. The hydroxyl nightglow has been examined anew using calculated rate constants for the key reactive and inelastic O + OH(v ) quenching processes. These constants have been obtained from quasiclassical trajectories run on the adiabatic ab initio-based double many-body expansion-IV potential energy surface for the ground state of the hydroperoxil radical. Significant differences in the vertical profiles of vibrationally excited hydroxyl radicals are obtained relative to the ones predicted by Adler-Golden (1997) when employing an O + OH(v ) effective rate constant chosen to be twice the experimental value for quenching of OH(v = 1). At an altitude of 90 km, such deviations range from ∼ 80 % for v = 1 to only a few percent for v = 9. Other mechanisms reported in the literature have also been utilized, in particular those that loosely yield lower and upper limits in the results, namely sudden-death and collisional cascade. Finally, the validity of the steady-state hypothesis is analysed through comparison with results obtained via numerical integration of the master equations.

Several notes on the OH* layer

“…(15) is proportional to the vibrationally dependent coefficient of Eq. (16), growing in the direction of the smaller v, as is well known from earlier results of modeling and measurements (e.g., Sivjee and Hamwey, 1987;Lopez-Moreno et al, 1987;McDade, 1991;Adler-Golden, 1997;Xu et al, 2012;Caridade et al, 2013).…”

Accurate combined-hyperbolic-inverse-power-representation of ab initio potential energy surface for the hydroperoxyl radical and dynamics study of $\bf O+OH$O+OH reaction

“…59,60 Recently, Carty et al 5 reported measurements of the rate constant for the O + OH reaction in the temperature range 39 ≤ T/K ≤ 142 and observed no variation with temperature, which led them to conclude that it would largely remain constant between 39 K and 10 K, temperatures typical of cold interstellar clouds. A review 61 on complex-forming reactions like O + OH and a recent application of rate constants calculated 62 for the latter on DMBE IV to model the OH nightglow in the atmosphere 63 are also available.…”

Resolving the mesospheric nighttime 4.3 µm emission puzzle: comparison of the CO<sub>2</sub>(<i>ν</i><sub>3</sub>) and OH(<i>ν</i>) emission models

“…Additionally, for OH(ν < 5) collisions with O( 3 P), which are considered completely inelastic, we used the rate coefficient 5 × 10 −11 cm 3 s −1 from Caridade et al (2013). The rate coefficient for the reaction O( 1 D) + N 2 (0) (Reaction R5 in Table 1) was taken from Sander et al (2011) with accounting for the fact that 33 % of the electronic energy is transferred to N 2 (Slanger and Black, 1974) producing, on average, 2.2 N 2 vibrational quanta.…”