15min:

JOHN A. COXON, Department of Chemistry, Dalhousie University, Halifax, Nova Scotia B3H 4J3, Canada; PHOTOS G. HAJIGEORGIOU, Department of Biosciences, Intercollege, Nicosia, Cyprus.

A collection of 6070 spectroscopic line positions for hydrogen fluoride and deuterium fluoride, which consists of all microwave and infrared X^{1 +} ground electronic state data, and the B^{1 +} - X^{1 +} emission band system data, has been employed in a weighted least-squares fit directly to the radial Hamiltonian operators of the B^{1 +} and X^{1 +} electronic states. The radial Hamiltonian operator model includes first- and second-order corrections to the Born-Oppenheimer approximation and was derived from the landmark theoretical work of Watson. The principle~isotopomer fitting strategy of Le Roy was incorporated in the least-squares fit. A total of 54 adjustable parameters was required to obtain a satisfactory representation of the experimental data, with a reduced standard deviation of 1.03. In addition, a collection of highly accurate quantum-mechanically meaningful rotational and centrifugal distortion constants was calculated from the derived Hamiltonian operators of the two electronic states.