15min:

J. D. TANDY, J.-G. WANG AND P. F. BERNATH, Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK.

The A² -X^{2 +} transition of BaOD has been rotationally analyzed using high-resolution laser excitation spectroscopy. BaOD molecules were synthesized in a Broida-type oven and detected using a single mode Ti:Sapphire laser. Measured rotational lines have been assigned, and rotational and fine structure parameters determined through a combined least-squares fit with the millimeter-wave pure rotational data of the X^{2 +} state. A significantly different spin-orbit coupling constant from the corresponding value for BaOH was observed and attributed to global and local perturbations arising from vibrationally excited bands of the A'² state. -doubling constants for the A² state also showed poor agreement with the predictions of the pure precession model. To further understand the nature of the interactions between the B^{2 +}, A² and A'² states of BaOH, a V-type optical-optical double resonance spectroscopy experiment was prepared to locate the lower-lying excited state levels. Preliminary results have yielded a band in close proximity on the lower wavenumber side of the A² _1/2 spin component of BaOH with a relatively large p value. Further results of this ongoing experiment will be presented.