Submission Date

4-28-2025

Document Type

Paper

Department

Physics & Astronomy

Second Department

Chemistry

Adviser

Ross Martin-Wells

Second Adviser

Mark Ellison

Committee Member

Ross Martin-Wells

Committee Member

Mark Ellison

Department Chair

Casey Schwarz

Department Chair

Mark Ellison

External Reviewer

Valentino Cooper

Distinguished Honors

This paper has met the requirements for Distinguished Honors.

Project Description

The mechanism and fundamental molecular properties involved in proton conduction are discussed. Four calculable properties are presented: the proton affinity, binding energy (between protonated and neutral forms), intramolecular tautomerization barrier, and proton hopping barrier. An overview of the computational methods used in this thesis, including an introduction to the many-body Schrödinger equation and Density Functional Theory, as well as a look at Plane-Wave Density Functional Theory and Gaussian-Type Orbital Density Functional Theory are presented. 4,5-dimethyl-[1,2,3]-triazole is used as a model system, with 10 variations being generated with varying amounts and positions of fluorine substitution on the methyl groups. Preliminary calculations of proton affinities and tautomerization barriers were completed using Density Function Theory, and the results discussed, as well as comparisons of calculated properties in plain [1,2,3]-triazole to experimentally determined activation energies for proton conduction. It was determined that in the orthorhombic crystal phase of [1,2,3]-triazole that the barrier to intramolecular tautomerization is likely the highest-energy barrier, and calculated results are shown to match closely with experimental data. In the liquid phase of [1,2,3]-triazole, the proton hopping barrier was shown to be the most likely highest-energy barrier, with calculated results closely matching experimental data. The currently available calculations of the proton hopping barriers are discussed, and future directions are established. In addition, the implications of binding energies on the distribution of conformers in a liquid phase are discussed, and a map of eight identified conformers of 4,5-dimethyl-[1,2,3]-triazole and 4,5-dimethyl-[1,2,3]-triazolium with their relative binding energies are presented and discussed. The results presented provide insight into the decisions made during the design of novel proton conducting materials, and promise to improve our understanding of proton conduction.

Comments

This work used resources of the National Energy Research Scientific Computing Center (NERSC) under NERSC award BES-ERCAPm4305.

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