It is shown that an intersecting parabola model with a horizontal displacement which has a square dependence on the reaction energy can lead to a range of free-energy relationships that encompasses those depicted by the Marcus inverted region, the Rehm-Weller behaviour and a novel "double-inverted region". The intersecting-state model is employed to interpret the experimental rates of electron transfer in organic systems which illustrate the three different types of behaviour described. © 1991.
Arnaut, L. G., & Formosinho, S. J. (1991). Free-energy relationships in organic electron transfer reactions. Journal of Molecular Structure: THEOCHEM, 233(C), 209–230. https://doi.org/10.1016/0166-1280(91)85065-F