58th Annual Report on Research 2013 Under Sponsorship of the ACS Petroleum Research Fund

Electron transfer process in ionic fluid is studied under linear response approximation with a molecule Debye-Hückel theory. The reorganization energy which serves as a central concept in Marcus' theory, could be derived from the free energy profile for reactant or product. As a consequence of linear response, the free energy profile is a quadratic function of a reaction coordinate such as the vertical energy gap. Furthermore, it is noted that the fluctuation and mean value of the vertical energy gap are related to each other by the fluctuation-dissipation relation, and hence both of them could be used to evaluate the reorganization energy. Our molecule Debye-Hückel theory could be used to calculate the mean value of the vertical energy gap, from which the reorganization energy is calculated.

Out theory is applied to electron transfer process in an electric cell, where the reorganization energy from molecule dynamics simulations could be well reproduced by our theory prediction, which demonstrates the accuracy of our theory.

We also further developed the molecular Debye-Hückel theory using density functional theory to accurately determine the expansion coefficients of the mean potential in terms of various Debye modes.

Two manuscripts based this work is in the process of submitting to Journal of Chemical Physics.