EXCIPLEX VACUUM-ULTRAVIOLET EMISSION-SPECTRA OF KRAR - TEMPERATURE-DEPENDENCE AND POTENTIALS

The temperature dependence of the emissions from the 0(+)(P-3(1)) and 1(P-3(2)) KrAr exciplex states in the range 85-350 K was studied usin g time resolved techniques, vacuum ultraviolet synchrotron radiation, and argon samples doped with minimal amounts of krypton. As the temper ature is increased, the emission shifts to the blue, its width increas es by almost a factor of 2, and the line shape becomes asymmetrical. T he experimental line shapes have been simulated by means of Franck-Con don density calculations using the available ground state potential of Aziz and Slaman [Mol. Phys. 58, 679 (1986)] and by modeling the excip lex potentials as Morse curves. The potential parameters for the 0(+) and 1 states are r(e) = 5.05 +/- 0.01 and 5.07 +/- 0.01 a(0), respecti vely; D-e = 1150 +/- 200 cm(-1) and beta = 1.4 +/- 0.1 a(0)(-1) for bo th states. The latter two values yield omega(e) = 140 cm(-1) and omega (e)x(e) = 4.3 cm(-1). The energy positions of the exciplexes's wells a nd their depths are compared with published results. (C) 1996 American Institute of Physics.