THE LONG-RANGE POTENTIAL OF THE K-2 X(1)SIGMA(-STATE UP TO 15 ANGSTROM()(G) GROUND ELECTRONIC)

Titanium sapphire laser induced fluorescence spectra of the A (1) Sigm a(u)(+) --> Chi (1) Sigma(g)(+) electronic system have been recorded a t high resolution by Fourier transform spectroscopy. Ground state vibr ational levels are observed up to nu = 81 corresponding to an internuc lear distance of 15.4 Angstrom and to 99.96% of the potential well dep th. A long range study of the potential energy curves (RRR and IPA) al lowed the determination of the coefficients of the dispersion energy ( multipolar expansion representation) and of the exchange energy (expon ential representation). The dissociation energy is found to be 4450.75 +/- 0.15 cm(-1). (C) 1995 American Institute of Physics.