A novel theoretical model for discussing the electron transfer reactivity is presented in this paper and also is calibrated in terms of the monohydrated vanadium ion system, V2+OH2/V3+OH2. The detailed calculations have been made at the UMP2(full)/6-311+G* level. The relevant energy quantities (such as the activation energy, dissociation energy, et al.) have also been obtained at different levels of theory (HF, MP2, MP3, MP4, and QCISD and corresponding spin-projection PUHF, PMP2, and PMP3) with the same basis set (6-311+G*) and valence electron correlation. The electronic transmission coefficient is calculated using the ab initio potential energy surface slopes, and the coupling matrix element determined from the two-state model and the Slater-type d-electron wave functions. The relevant kinetic parameters are obtained in terms of new schemes presented in this paper. The contact distance dependence of these parameters and the applicability of the presented models are also discussed.