Concerning the problem of the isokinetic relationship. II. The physical significance of the degrees of freedom in the statistical-mechanical model

Abstract

The statistical model presented recently for the isokinetic relationship is developed. The physical meaning of the degrees of freedom (s) is explained in terms of ∆Cp‡, i.e. the change in the specific heat between ground and activated states: ∆Cp‡ =-(s-1)R In the case where (s-1)/(E/kBT) cannot be neglected the relationship is ∆Cp‡=-(s-1)(1-kBT/E)R where E denotes the potential barrier height. The results from a digital fitting procedure for the complete form of the model are compared with those obtained from the simplified equations for 'energy-barrier-controlled' reaction series.