15min:

CORINNA EMMELUTH, CHRISTOPHER D. THOMPSON, BERWYCK L. J. POAD AND EVAN J. BIESKE, Laser Spectroscopy Group, School of Chemistry, University of Melbourne, Parkville, VIC 3010 Australia; GARY H. WEDDLE, Fairfield University, Department of Chemistry, Fairfield, CT 06430 USA.

Photodissociation infrared spectra of mass selected LiD₂⁺ and LiH₂⁺ have been obtained in the D-D and H-H stretch region respectively, using a tandem mass spectrometer and detecting the Li⁺ loss channel. For the first time rotationally resolved spectra of these complexes are available providing structural parameters and allowing direct comparison with theoretical data~. For LiD₂⁺ around 100 lines of the K _a=0 K _a=0, K _a=1 K _a=1, and K _a=2 K _a=2 parallel transitions were fitted to a Watson A-reduced Hamiltonian. The analysis of the spectrum was supported by quantum chemical calculations using the program TRIATOM~ and the potential from Gianturco et al. ~. The LiD₂⁺ complex was found to have T-shaped structure in agreement with theoretical predictions. An analogous analysis has been performed for the LiH₂⁺ spectrum which differs from the LiD₂⁺ spectrum due to larger rotational constants and an altered ortho:para ratio.