15min:

MING-WEI CHEN, GABRIEL M. P. JUST, TERRANCE CODD AND TERRY A. MILLER, Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 W. 18th Avenue, Columbus, Ohio 43210.

The three energetically lowest electronic states (X ²A₂', A ²E'', and B ²E') of NO₃ are strongly coupled by vibronic interactions and have been treated in considerable detail theoretically.\footnoteJ. F. Stanton, J. Chem. Phys. , \underline\textbf126, 134309 (2007) Corresponding experimental characterization of the interaction is much less detailed. Previous experimental results primarily consist of IR measurements of vibrational transitions in the ground state.\footnoteK. Kawaguchi, E. Hirota, T. Ishiwata, and I. Tanaka, J. Chem. Phys. , \underline\textbf93, 951 (1990)\footnoteK. Kawaguchi, T. Ishiwata, E. Hirota, and I. Tanaka, Chem. Phys. , \underline\textbf231, 193 (1998) In addition, the electronically forbidden A-X transition has been observed in ambient temperature CRDS studies.\footnoteA. Deev, J. Sommar, and M. Okumura, J. Chem. Phys. , \underline\textbf122, 224305 (2005)\footnoteE. Hirota, T. Ishiwata, K. Kawaguchi, M. Fujitake, N. Ohashi, I. Tanaka, J. Chem. Phys. , \underline\textbf107, 2829 (1997) A slit-jet nozzle with a high voltage pulsed discharge has been applied to produce the NO₃ radical by dissociating the N-O bond of N₂O₅, and the jet-cooled NO₃ CRDS absorption spectrum has been successfully observed with a high-resolution laser source ( ~250MHz, intrinsic resolution considering the instrumental linewidth and the residual Doppler broadening in the jet). The 4¹₀ band (parallel band) shows complex rotational structure which is presently being analyzed. The 2¹₀ band has also been measured as an example of a perpendicular band. Besides the ₂ and ₄ vibronic bands, the vibronically forbidden origin band (0⁰₀ band) has been recorded under the same experimental conditions. The weakly observed A-X origin band is likely either a magnetic dipole or an electric quardrupole transition.