Phenomenological treatment of chemical relaxation data

Abstract

Ultrasonic relaxation and T- or p-jump studies of a single chemical relaxation process yield a relaxation time τ and a relaxation amplitude. By use of linear phenomenological theory expressions are derived which, in suitable cases, enable the thermodynamic and kinetic contributions to τ to be monitored separately. For elementary reactions in particular these expressions show that the behaviour of amplitude divided by τ can lead to direct information concerning the behaviour of forward and backward rates. The treatment can be used in cases where conventional methods based on mass-action kinetics are no longer convenient. It is applicable to data as obtained both in ideal and non-ideal systems and may facilitate the search for a suitable kinetic model.