Dynamics and mechanisms of hot chemistry stimulated by recoil methods. Progress report, March 1, 1975--February 29, 1976

A technique for the quantitative investigation of vibrational energy transfer efficiencies at very high levels of excitation is described. In this method chemical activation by nuclear recoil reaction is utilized and the competitive stabilization-decomposition characteristics of the resulting unimolecular system are probed as a function both of pressure and bath gas composition. The relative energy transfer efficiencies for collisions between excited cyclobutane-t and He, Ne, Ar, Kr, Xe, N2, CF4, c-C4H8 are reported. The hot atom reaction between nuclear recoil chlorine atoms and hydrogen gas to produce translationally excited hydrogen chloride is reported. A sizable hydrogen isotope effect was observed in this system between H2 and D2 reactant and there appears to be a cross over from normal to inverse isotope effect as the relative laboratory collision energy is increased above the thermal threshold region. Evidence for electronically excited S(1D) reactions of nuclear recoil produced sulfur atoms is reported on the basis of relative product yields as a function of electronic energy quenching additives