Systems with variable pre-exponentials

It has been shown that variations in Ed with coverage can be used to explain the non-linearity of kinetic plots. However, such deviations can also be explained by pre-exponential variations and, in most cases, a shift of Ed or v values, or more rarely, a change in both together, can be used to fit experimental data successfully. A further problem with a simple analysis is that compensation effects between parameters can make the system appear simple, while give misleading values for kinetic terms. Most experiments assume a constant v, because of the difficulties of making accurate measurements of the pre-exponential. Experiments which have assumed a dependence of Ed on 6 can also be explained by applying a 

It is believed that v and Ed can be linked together by a compensation effect and Cassuto et al. [278] have shown this intrinsically. They used the relationship 

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