VIBRATIONAL PREDISSOCIATION DYNAMICS OF ARHF (3000) AND (3110) - LIFETIMES AND HF PRODUCT STATE DISTRIBUTIONS

The lifetimes and HF (upsilon=2) product rotational distributions (j'= 13 to 9) arising from the vibrational predissociation of ArHF (3000) a nd (3110) states have been determined by laser-induced dispersed fluor escence. The lifetimes of (3000) and (3110) are found to be 3.9(4)x10( -6) and 7.3(8)x10(-6) s, respectively, showing both intermolecular vib ration and HF valence state dependence. The variation in the vibration al predissociation rate for these two states indicates a strong angula r dependence of the change of interaction potential with the HF intern uclear distance in the complex. The product state distribution of ArHF (upsilon=3) reveals the excess energy, 3380 cm(-1), resulting from vi brational predissociation (Delta upsilon=-1) is partitioned primarily into HF product rotation. The rotational distribution observed followi ng excitation of the (3110) level is considerably broader than the rel atively sharply peaked distribution from (3000). The upsilon(HF)=3 gro und stare, (3000), vibrationally predissociates into j'=13 at a rate o f tau(vp)=1.2x10(5) s(-1), which is one half of the rate of predissoci ation to all states. (C) 1998 American Institute of Physics. [S0021-96 06(98)00644-8].