15min:

TERRANCE J. CODD, MOURAD ROUDJANE AND TERRY A. MILLER, Laser Spectroscopy Facility, The Ohio State University, Columbus, Ohio 43210.

The ²E''A state of NO₃ is doubly degenerate and is therefore subject to Jahn-Teller (JT) distortion. In the A state there are two JT active modes, ₃ and ₄ (e' stretch and in plane bend respectively). Theoretical work has predicted that the JT effect in the A state should be quite strong and approach the static case (D\geq1) where the molecule is permanently distorted to a lower symmetry geometry. A moderate resolution spectrum of the A state showed a feature that we tentatively assigned as the 3¹₀ band based on position and band contour. Using high resolution cavity ringdown spectroscopy we have now obtained a rotationally resolved spectrum of this band. The analysis of this band has been commenced using an oblate symmetric top Hamiltonian with spin-rotation terms. This analysis supports the assignment of this band to the a₁'' vibronic component of the 3¹₀ band. So far, the spectrum shows no evidence of a large geometric distortion of the molecule. Some lines appear to be split, as was previously observed in the 4¹₀ and 4²₀ bands, and the possible sources of this splitting are being investigated.