Specific Rate Constants of Unimolecular Processes II. Adiabatic Channel Model

Abstract

Abstract The rate of unimolecular processes is calculated by means of a statistical adiabatic channel model. The rates are mainly determined by the maxima of the channel energies. The channels are constructed by correlating reactant and product states; the channel energies are computed by a simple interpolation procedure. The coupling between the various vibrational‐rotational motions is taken into account. The influence of parameters of the potential surface on channel energies and on rate constants is studied. Numerical results for the NO 2 , CH 4 , CD 4 , C 2 H 6 and C 2 D 6 dissociation – recombination kinetics are compared to experimental data. The statistical adiabatic channel model gives similar results as minimum local entropy models. Both these approaches lead to stronger curvatures of k(E) and smaller activation energies for the thermal rate constant k ∞ than the corresponding RRKM calculations.