VIBRONIC ANALYSIS OF THE $\widetilde{A}^2 E^{\prime\prime}$ STATE OF NO$_3$ RADICAL
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Date
2013
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Publisher
Ohio State University
Abstract
The nitrate radical is a key reactant in atmospheric chemistry leading to the formation of acid rain and is the primary oxidant in the night sky. The $\widetilde{A}^2 E^{\prime\prime}$ state of NO$_3$ is doubly degenerate and is therefore subject to Jahn-Teller (JT) coupling through the degenerate in-plane stretch and bend modes ($\nu_3$ and $\nu_4$ respectively). We have taken a moderate resolution CRDS spectrum of the $\widetilde{A}^2 E^{\prime\prime}$-$\widetilde{X}^2 A_2^{\prime}$ transition of the NO$_3$ radical under jet-cooled conditions. We resolve $\sim20$ vibronic transitions and are able to assign many using an independent anharmonic oscillator model as was presented previously. {Codd, T. et al. 67th Int. Symp. Molec. Spec. (2012)} In order to gain a deeper understanding of the nature of the JT effect in this electronic state we have performed a vibronic analysis including linear and quadratic JT coupling terms for $\nu_3$ and $\nu_4$ and possible bilinear coupling between the totally symmetric stretch, $\nu_1$, and $\nu_4$. We conclude that the JT coupling in $\nu_4$ is quite weak. Satisfactory spectral fits can be obtained assuming weak JT coupling for $\nu_3$ also, though there is some evidence of strong JT coupling for $\nu_3$ and the strengths and weaknesses of each case are discussed.
Description
Ming-Wei Chen present address: University of Illinois at Urbana-Champaign, Urbana, IL, 61801
Author Institution: Laser Spectroscopy Facility, The Ohio State University, Columbus, Ohio 43210
Author Institution: Laser Spectroscopy Facility, The Ohio State University, Columbus, Ohio 43210