Solvent dynamics, vibrational effects and nuclear tunneling in electron transfer reactions
Abstract
The work presented in this thesis is an investigation of a variety of theoretical, experimental and computational aspects of electron transfer. The aspect of crucial importance in this work is the manner in which nuclear motions of the solvent and reactants are coupled to the reaction coordinate of electron transfer reactions. The solvent surrounding a reaction complex affects the rate of electron transfer reactions both by means of an energetic barrier which must be surmounted in order for them to be reorganized and the time scale necessary for this reorganization to occur. The kinetics of three sesquibicyclic hydrazines were measured in a series of solvents which have varying solvent relaxation times. These hydazines have substantial inner shell barriers to electron transfer as a consequence of a large conformational change in concert with an electron transfer. The solvent-dependent rates were compared with numerical results utilizing the theoretical work of Sumi and Marcus and the numerical method of Nadler and Marcus. The poor fit of the data to the Sumi-Nadler-Marcus approach led us to modify their theory to include nuclear tunneling effects with the result that our data are now in better but not still not quantitative accord with the predictions of a modified Sumi-Nadler-Marcus. Other work includes a molecular dynamics study of the nuclear dynamics of methanol in response to an electron transfer in which it was shown that inertial effects dominate early time dynamics and that deviations from linear response theory exist which depend on a solutes' size and charge. A study of electron transfer self-exchange rates for a series of metallocenes in the gas phase suggests that the extent of donor-acceptor orbital overlap can effect gas-phase kinetics. The earliest work is present in the publications produced in collaboration with A. Kornyshev and A. Kuznetzov in which a new nonlocal solvent dynamics theory was investigated. In addition nonlocal electrostatics and ionic atmosphere effects on electron transfer reactions were studied.
Degree
Ph.D.
Advisors
Weaver, Purdue University.
Subject Area
Chemistry
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