MODERATE RESOLUTION JET COOLED CAVITY RINGDOWN SPECTRA OF THE $\tilde{A}$ STATE OF NO$_3$ RADICAL
Loading...
Date
2012
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The $\tilde{A}$-$\tilde{X}$ spectrum of NO$_3$ has been previously observed using cavity ringdown spectroscopy (CRDS) by Andrei Deev \emph{et. al} under ambient conditions. There the authors assigned a number of vibronic bands in the spectrum. However, under these conditions, hot-bands may be present and the spectrum becomes very congested at frequencies higher than $\sim$8700 cm$^{-1}$ due to the density of vibronic states and the overlap of their rotational contours. In order to obtain more information about the $\tilde{A}$ state of NO$_3$ we recently obtained spectra from 7550 cm$^{-1}$ to over 10000 cm$^{-1}$ using our moderate resolution ($\simeq$ 0.05 cm$^{-1}$) jet cooled CRDS apparatus. Jet cooling in our apparatus reduces the rotational temperature to $<$30 K and eliminates vibrational hot bands greatly simplifying the spectrum. We are able to resolve and assign more than 15 vibronic features including a new assignment of the 3$^{1}_0$ band. Analysis of the $\nu_4$ progression shows weak Jahn-Teller coupling in this mode. Anomalous band contours and anharmonic spacings are observed for the $\nu_1$$\nu_4$ combination bands and the cause is being investigated. We also see some features that could belong to vibronically forbidden transitions which may be magnetic dipole allowed.
Description
Author Institution: Laser Spectroscopy Facility, The Ohio State University, Columbus, Ohio 43210
Ming-Wei Chen present address: University of Illinois At Urbana-Champaign, Urbana, IL, 61801
Ming-Wei Chen present address: University of Illinois At Urbana-Champaign, Urbana, IL, 61801