STATE-TO-STATE REACTIVE SCATTERING OF F-2 IN SUPERSONIC JETS - NASCENT ROVIBRATIONAL HF(V,J) DISTRIBUTIONS VIA DIRECT IR LASER-ABSORPTION(H)

Pulsed discharge sources of supersonically cooled F radicals have been crossed with supersonically cooled H-2 to study the F(P-2(3/2),P-2(1/ 2)) + H-2-->HF(v,J) + H reaction under single collision conditions wit h a collision energy of 1.8(2) kcal/mol. The HF(v,J) product states ar e probed via direct absorption of a single mode, tunable near IR laser perpendicular to the plane of intersection of the two jet axes. The h igh spectral resolution (Delta v approximate to 0.0001 cm(-1))permits the quantum state HF(v,J)distribution to be determined with complete r esolution of final rovibrational levels. The J-dependent integral cros s sections for HF(v=3,J) are compared with exact quantum scattering ca lculations by Castillo and Manolopoulous on the ground adiabatic poten tial energy surface of Stark and Werner. Agreement between theory and experiment is quite good for low J (<3) states. However, theory substa ntially underpredicts the experimental distributions for high J(greate r than or equal to 3) states near the energetic cutoff for ground spin orbit state F(P-2(3/2)) atoms, which may indicate the presence of non -adiabatic reaction channels involving spin orbit excited F(P-2(1/2)) atoms. (C) 1997 American Institute of Physics.