ENERGY DEPENDENCIES OF FAST REACTIONS OF POSITIVE-IONS X+ WITH HCL FROM NEAR THERMAL TO SIMILAR-OR-EQUAL-TO-2 EV CENTER-OF-MASS COLLISION ENERGY (X+=H+,H-2+,H-3+,N+,N-2+,AR+,C+,CH+,CH-2+,CH-3+,CH-4+,CH-5+)

The rate coefficients for the reactions of the ions H+, H-2+, H-3+, N+, N2+, Ar+, C+, CH+, CH+2, CH3+, CH4+, and CH5+ with HCI have been measured as a function of reactant ion/reactant neutral average center-of-mass kinetic energy (KE(c.m.)). The measurements were performed using a selected ion flow drift tube operated at 300 K with helium buffer gas. Most of these reactions have rate coefficients close to their collisional values at ambient temperature and all of them exhibit a pronounced KE(c.m.) dependence. A simple model is proposed, in which the measured dependence of the rate coefficients on KE(c.m.) is expressed in terms of the kinetic-energy dependence of the rate unimolecular decomposition of the intermediate complex formed in the ion-neutral collision.