ESTIMATION OF ACTIVATION ENERGIES FOR NITROUS OXIDE, CARBON DIOXIDE, NITROGEN DIOXIDE, NITRIC OXIDE, OXYGEN, AND NITROGEN REACTIONS BY A BOND-ENERGY METHOD

A trial method is described for estimating the activation energies of bimolecular transfer reactions of such multivalent gaseous compounds as O2, N2, NO, N2O, NO2, CO, and CO2. It is also applicable when the monatomic reactants O, N, and H, and the OH radical are involved. The method uses trial relationships between bond dissociation energy, bond length, and bond order. This semiempirical calculation avoids the use of adjustable parameters. The agreement between calculated and experimental activation energies is very good when spin conservation in the transition state is considered in the computation procedure. Spin conservation is applied specifically to N2O and CO2 transfer reactions. A convenient rule has also been formulated that predicts the activation energy will be negligible in exothermic bimolecular reactions between radicals when the transition-state formula corresponds to that of a compound having stable bonds. No exceptions to this rule have been found.