15min:
OBSERVATION OF LOW J TRANSITIONS OF LASER ABLATED ALKALI HALIDES.

BROOKE A. TIMP, JAMIE L. DORAN, KENNETH R. LEOPOLD, Department of Chemistry, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN 55455; JENS-UWE GRABOW, Institut f\ddotur Physikalische Chemie und Elektrochemie, Gottfried-Wilhelm-Leibniz-Universit\ddotat Hannover, Callinstraße 3A, 30167 Hannover, Germany.

Pulsed nozzle Fourier transform microwave spectroscopy has been used to observe low J transitions (J = 1 leftarrow 0 and J = 2 leftarrow 1) of several alkali halides produced by 532 nm laser ablation of pressed pellets. Spectra were readily located using predictions based on literature constants derived from higher J transitions but improvements of 10 to 100 kHz in spectral line positions are obtained. The additional accuracy could prove useful for astrophysical identification. The 41K isotopologue of KBr has been observed for the first time. Ablation of a mixed pellet of KCl and NaBr produces spectra of NaCl, indicating exchange between species produced by the ablation event. Aspects of the new experimental apparatus will be reported.