New measurements of the a(3)Sigma(+)(u) state of K-2 and improved analysis of long-range dispersion and exchange interactions between two K atoms

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 optical-optical double resonance (PFOODR) technique. Data have been fit to an improved set of molecular constants for the a(3) Sigma(u)(+) state. In particular, the new T-e value for this state has been determined 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 analysis of long-range dispersion and exchange interactions between two K atoms 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), respectively. (C) 1996 American Institute of Physics.