Date of Award

2022

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Graduate Group

Chemistry

First Advisor

Joseph E. Subotnik

Second Advisor

Jeffery G. Saven

Abstract

Current methods for modeling electron transfer (ET) dynamics in electrochemical systems rely on boundary condition based methods that often obfuscate any nonadiabatic effects. However, these nonadiabatic effects can play critical roles in many key electrochemical systems, such as ET events coupled to proton transfer, or systems where ET occurs between metal adsorbed redox species and the metal. In this dissertation we present new methods and algorithms for modeling and simulating electrochemical systems exhibiting nonadiabatic effects. First, we examine whether electron friction dynamics can be used in lieu of surface hopping generally for nonadiabatic dynamics. We find that electronic friction is only applicable in specific situations, and that in general a broadened classical master equation solved with surface hopping must be applied in the weak molecule-metal coupling limit. Next, we outline a surface hopping approach for modeling sweep voltammetry experiments, and show a technique for mapping multidimensional, diffusional electrochemical systems to reduced, lower dimensional systems. This surface hopping approach is used to study proton coupled electron transfer (PCET), whereby nuclear quantum effects are incorporated through an explicit proton coordinate. Finally, we present a spatially grid-free algorithm for simulating the above electrochemical systems (including systems where inner-sphere effects are included, such as adsorption), and also demonstrate its computational efficacy in comparison to current simulation techniques common in the field of electrochemistry.

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