Approximate Quantum Numbers in the Optical Spectrum of $NO_{2}$

Thumbnail Image



Journal Title

Journal ISSN

Volume Title


Ohio State University

Research Projects

Organizational Units

Journal Issue


The optical spectrum of $NO_{2}$ obtained in jet expansion fluorescence spectra by Persch et. al. [1], providing data on band origins shows a highly mixed spectrum with near-GOE level statistics, including level-repulsion. Microwave-detected microwave optical double resonance data obtained in our work [2], providing data on the distribution of levels at higher angular momentum, shows an ergodic spectrum with no detectable level repulsion. We examine the two data sets in the light of a multiple bright state model [3], and a related K-breakdown or weak-breakdown model. We find that the band origin data is consistent with a multiple bright state model with approximatley 4 bright states mixed into each observed state. The high J data is consistent with the K-breakdown model in which Coriolis-coupling matrix elements are much smaller than the bright state - dark state vibronic interaction. An experimental test of this model is proposed. This indicates that the presence of approximately conserved quantum numbers in a molecular spectrum complicates the application of statistical measures of ergodicity.


1. G Persch, E Mchdizadeh, W Demtroder, Th Zimmermann, H Koppel, and LS Cederbaum, Ber. Bunsenges. Phys. Chem. 92, 312(1988). 2. KK Lehmann, SL Coy, Ber. Bunsenges. Phys. Chem. 92, 306(1988). 3. SL Coy, KK Lehmann, Phys. Rev. A 40, 5935 (1989).""
Author Institution: Massachusetts Institute of Technology, , 18 Vassar Street Rm. 6-234B; Princeton University, Department of Chemistry