From quantum chemistry to dissociation kinetics: what we need to know

The relationship between rate constants for dissociation and the reverse association reactions and their potential energy surfaces is illustrated. The reaction systems e(-) + SF6 <-> SF6- -> SF5- + F, H + CH3 <-> CH4, 2 CF2 <-> C2F4, H + O-2 -> HO2, HO + O <-> HO2 <-> H + O-2, and C + HO -> CHO are chosen as representative examples. The necessity to know precise thermochemical data is emphasised. The interplay between attractive and anisotropic components of the potentials influences the rate constants. Spin-orbit and electronic-rotational coupling in reactions between electronic open-shell radicals so far generally has been neglected, but is shown to have a marked influence on low temperature rate constants.