Chemical relaxation as a transport process

Abstract

Linear response theory is used to obtain a linearized Boltzmann equation for the species concentration of a bimolecular reaction. The perturbation which induces the reaction is taken to be the change in the chemical affinity times the progress variable per unit volume. The density-density spectral function is computed from a perturbation expansion, selecting the diagrams which contribute in the low density limit. An expression for the relaxation time due to the chemical reaction is obtained from the linearized Boltzmann equation, in terms of the cross-section of the intermolecular process. Sound absorption and dispersion are considered similarly, including corrections due to viscosity and thermal difussion.