Quantitative Hammond postulate

Noam Agmon
1978 Journal of the Chemical Society Faraday Transactions 2 Molecular and Chemical Physics  
In this paper four assumptions are made : (1) Pauling's relation (2) Bond order conservation, (3) An approximation for the potential energy along the reaction coordinate and (4) a symmetry principle. The main results which follow are : (a) An expression for the bond order of the transition state, a result which is compared with potential energy surfaces, BEBO and Marcus' theories. (b) A theoretical fit for (nonlinear) Bronsted plots over a mild range of ApK. In addition, other theories which
more » ... r theories which relate kinetics to thermodynamics (in particular : BEBO, Marcus' theory and Thornton's model) are analysed. Two empirical relations of Mok and Polanyi and the Evans-Polanyi relation are derived by using the symmetry principle. Marcus' theory may be related to a " weak symmetry principle " ; this theory is given a new proof by Thornton's model of the inverted parabola. Thus these theories appear to have much in common ; it is possible that they all follow from one general theory.
doi:10.1039/f29787400388 fatcat:kljo3hw4nvhllmg6ovrhjo3ix4