15min:

JOHN A. COXON, Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4J3, Canada; PHOTOS G. HAJIGEORGIOU, Department of Life and Health Sciences, University of Nicosia, 46 Makedonitissas Avenue, P.O Box 24005, 1700 Nicosia, Cyprus.

A set of 16544 A¹ _u⁺ - X¹ _g⁺ fluorescence line positions with a measurement precision of 0.001 cm^-1, and which samples ground state levels up to '' = 135 lying about 28 cm^-1 below the dissociation limit, has been employed in least-squares fits using the MLR direct potential fitting approach . As well as the extended MLR model employed recently for Li₂, a further extension employing three y_i -variables leads to an optimum model for Cs₂ that ensures a realistic extrapolation into the long-range region in accord with the theoretical dispersion constants.