TY - JOUR
T1 - Quantitative Hammond postulate
AU - Agmon, Noam
PY - 1978
Y1 - 1978
N2 - 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) Brönsted plots over a mild range of ΔpK. In addition, other 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.
AB - 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) Brönsted plots over a mild range of ΔpK. In addition, other 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.
UR - http://www.scopus.com/inward/record.url?scp=37049106333&partnerID=8YFLogxK
U2 - 10.1039/F29787400388
DO - 10.1039/F29787400388
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:37049106333
SN - 0300-9238
VL - 74
SP - 388
EP - 404
JO - Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics
JF - Journal of the Chemical Society, Faraday Transactions 2: Molecular and Chemical Physics
ER -