NEW MEASUREMENTS OF THE A(3)SIGMA(-2 AND IMPROVED ANALYSIS OF LONG-RANGE DISPERSION AND EXCHANGE INTERACTIONS BETWEEN 2 K ATOMS()(U) STATE OF K)

Resolved fluorescence from the K-2 4(3) Sigma(g)(+) state to the a(3) Sigma(u)(+) state has been measured by the perturbation-facilitated op tical-optical double resonance (PFOODR) technique. Data have been fit to an improved set of molecular constants for the a(3) Sigma(u)(+) sta te. In particular, the new T-e value for this state has been determine d as 4197.935+/-0.047 cm(-1), nearly 1.8 cm(-1) higher than previously reported. By combining the new results for the a(3) Sigma(u)(+) State and the recent results for the ground X(1) Sigma(g)(+) state [J. Chem . Phys. 103, 3350 (1995)], we report in this paper an improved analysi s of long-range dispersion and exchange interactions between two K ato ms and of the X(1) Sigma(g)(+) and a(3) Sigma(u)(+) state dissociation energies D-e of 4450.674+/-0.072 cm(-1) and 252.74+/-0.12 cm(-1), res pectively. (C) 1996 American Institute of Physics.