15min:

JENS-UWE GRABOW, Gottfried-Wilhelm-Leibniz-Universität, Institut für Physikalische Chemie, Callinstraße 3A, 30167 Hannover, Germany; RICHARD J. MAWHORTER, Pomona College, Department of Physics and Astronomie, 610 North College Avenue, Claremont, CA 91711.

The mixed alkali halide dimer LiKF₂ has been observed and characterized using LASER-ablation supersonic-jet Fourier transform microwave spectroscopy. This is the first step in extending the earlier successful studies of LiNaF₂ to heavier mixed dimers.

Fifteen transitions of 3 isotopologues of LiKF₂, ⁶Li³⁹KF₂, ⁶Li⁴¹KF₂, and ⁷Li³⁹KF₂, have been observed. This allows a determination of the kite-shaped LiKF₂-structure as well as the leading centrifugal distortion constants, which in turn provide more insight into the nature of these ionic bonds. Measurements of the hyperfine splitting of these spectral lines provides another constraint on molecular charge density, i.e. a further detailed check of theoretical calculations.