Abstract
The microscopic descriptions of electron transfer (ET) reactions given by Marcus theory (MT) and by the intersecting-state model (ISM) are compared with ab initio calculations on O2/O2- and C6H6/C6H6- model systems. The activated configuration calculated by ab initio methods agrees only with that of ISM. Solvent effects in self-exchange rates and in intervalence bands of mixed-valence symmetrical compounds are shown to be smaller than predicted by dielectric continuum models. MT and ISM are used to calculate self-exchange and cross-reaction rates of transition-metal complexes and organic species. It is shown that a compensation of effects may take place in MT calculations. Absolute ET rate calculations using ISM are in good agreement with experiment when non-adiabatic factors are included in σ*(d) electron exchanges. It is shown that ISM reproduces different types of free-energy profiles (Rehm-Weller behaviour, Marcus inverted region, double inverted region) with only one adjustable parameter. The donor-acceptor distance dependence, temperature dependence and free-energy dependence of intramolecular ET reactions are calculated with two adjustable parameters. These calculations are within an order of magnitude of the experimental rates.
Keywords
Get full access to this article
View all access options for this article.
