ROTATIONAL, FINE, AND HYPERFINE STRUCTURE OF Ar$\cdot$OH/D VIBRONIC BANDS

1. Fawzy and Heaven, J. Chem. Phys. 92, 909 (1990). 2. Chang et. al. J. Chem. Phys. 95, 7086 (1991). 3. Chang et. al., 45th The Ohio State University Symposium on Molecular Spectroscopy TH5, June 11-15, 1990.Author Institution: Laser Spectroscopy Facility Department of Chemistry, The Ohio State UniversityThe rotational, fine, and hyperfine structure in the spectra of the Ar$\cdot$OH/D A $bands^{1}$ has been well studied and $reported^{2}$. In contrast, the spectra of the vibronic bands (U bands) have not been analyzed in detail. These U bands are $assigned^{1}$to transitions with one quantum of excitation in the bending mode in the $\tilde{A}$ state, and we first $reported^{3}$ the high resolution electronic spectrum two years ago. Due to the bending excitation in the A state, these U bands have a completely different vibronic symmetry from that of the A bands. As we reported, the spectrum of U bands shows a very different rotational contour. In addition, the fine and hyperfine structure is also very complicated and different from that of the A bands. Here, we present a complete spectral fit with a standard deviation of about 50 MHz for the U band spectrum including rotational, fine, and hyperfine structure. The details of the analysis and the physical interpretation will be discussed