Eyring absolute reaction rate model

Although the formulation of such a theory has never been achieved, Eyring s absolute reaction rate model [123] has several features in common with such theory. 

Bosse [48] proposed a new model to predict binary Maxwell-Stefan diffusion coefficients Dij, based on Eyrings absolute reaction rate theory [49]. A correlation from Vignes [50] which was shown to be valid only for ideal systems of similar-sized molecules without energy interactions [51] was extended with a Gibbs-excess energy term... 

An understanding of the mechanism of creep failure of polymer fibres is required for the prediction of lifetimes in technical applications. Coleman has formulated a model yielding a relationship similar to Eq. 104. It is based on the theory of absolute reaction rates as developed by Eyring, which has been applied to a rupture process of intermolecular bonds [54]. Zhurkov has formulated a different version of this theory, which is based on chain fracture [55]. In the preceding sections it has been shown that chain fracture is an unlikely cause for breakage of polymer fibres. 

Another moderately successful approach to the theory of diffusion in liquids is that developed by Eyring (E4) in connection with his theory of absolute reaction rates (P6, K6). This theory attempts to explain the transport phenomena on the basis of a simple model for the liquid state and the basic molecular process occurring. It is assumed in this theory that there is some unimolecular rate process in terms of which the transport processes can be described, and it is further assumed that in this process there is some configuration that can be identified as the activated state. Then the Eyring theory of reaction rates is applied to this elementary process. 

Chapter 8 provides a unified view of the different kinetic problems in condensed phases on the basis of the lattice-gas model. This approach extends the famous Eyring s theory of absolute reaction rates to a wide range of elementary stages including adsorption, desorption, catalytic reactions, diffusion, surface and bulk reconstruction, etc., taking into consideration the non-ideal behavior of the medium. The Master equation is used to generate the kinetic equations for local concentrations and pair correlation functions. The many-particle problem and closing procedure for kinetic equations are discussed. Application to various surface and gas-solid interface processes is also considered. 

The Eyring surface erosion model was applied together with the general absolute reaction rate theory to the rate of mass loss of meteors as they pass through the atmosphere. Atmospheric erosion of the heat shield of space vehicles upon reentry is a problem of great importance to which this theory is directly applicable. 

A simple picture of liquid flow of plain fluids has been developed by Eyring, using a free volume model and the theory of absolute reaction rates. Eyring s conception forms also the basis for some studies of liquid polymer flow, and a qualitative description of the ideas involved will be given in the following paragraph. 

Since the discovery of the deuterium isotope in 1931 [44], chemists have long recognized that kinetic deuterium isotope effects could be employed as an indicator for reaction mechanism. However, the development of a mechanism is predicated upon analysis of the kinetic isotope effect within the context of a theoretical model. Thus, it was in 1946 that Bigeleisen advanced a theory for the relative reaction velocities of isotopic molecules that was based on the theory of absolute rate —that is, transition state theory as formulated by Eyring as well as Evans and Polanyi in 1935 [44,45]. The rate expression for reaction is given by... 

Transition-state theory, that is treatment of chemical reactions as steady state processes, first devised by Evans and Polanyi [72] in 1935, has been widely used in modelling the absolute rate coefficients of reactions in both gases and liquids. Eyring s extension defining the volume of activation [73], has also been employed to interpret the pressure variation of rate coefficient data, often with mechanistic application. Activation volume is the particular facet of transition-state theory which has received application to reactions in supercritical fluids, especially in the immediate vicinity of the solvent gas-liquid critical point. Some of this work is reviewed below, beginning with a discussion of the validity of the use of transition-state theory in near-critical and supercritical fluids. 

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