Computed Activation Energies and Rate Constants for Forward and Reverse Transfers of Hydrogen Atoms.

摘要

Activation energies were computed for 324gas phase hydrogen-atom transfers between atoms of atomic numbers 1through 19 (excluding the inert gases) as well as Br and I. Eighteen exchange reactions and 153reverse reactions were included. A modification of the Johnston-Parr method that considers the temperature region in which the activated complex can be expected to obey small-vibration theory was used to calculate rate constants and rate-equation parameters from 298to 2500 K. Comparison of computed E(O) and k with experiment shows satisfactory agreement over this temperature range,except for the H2 + O = H +OH transfer. Contributions of the activated-complex vibrations and tunneling are discussed briefly. (Author)