Electronic Theses and Dissertations

Date of Award

1-1-2023

Document Type

Dissertation

Degree Name

Ph.D. in Chemistry

First Advisor

Gregory Tschumper

Second Advisor

Ryan Fortenberry

Third Advisor

Steven Davis

School

University of Mississippi

Relational Format

dissertation/thesis

Abstract

Computational quantum chemistry proves to be a highly effective means of exploring the nature and properties of a wide range of chemical systems that may be challenging to characterize experimentally. One area of particular interest is the investigation of non-covalent interactions, which play a crucial role in a wide variety of biological, chemical and physical processes. Obtaining accurate descriptions of systems dominated by weak inter- and intramolecular non-covalent interactions often requires sophisticated ab initio methods used in conjunction with robust basis sets. This approach, however, can become extremely computationally demanding as the size of the system of interest increases. Within part of this work, methods such as the highly efficient and accurate 2-body:Many-body and 3-body:Many-body techniques are utilized to probe the interaction between a single Ar atom and various small water clusters (H2O)n=3-6, providing the means for obtaining highly accurate results for larger systems at a much more reasonable computational cost. Many computational quantum chemistry techniques can also afford advantages in isolating these weak interactions of interest, such as symmetry adapted perturbation theory (SAPT), which provides a means of directly computing interaction energies between two systems of interest along with a separation of the total interaction energies into physically meaningful components (electrostatic, exchange-repulsion, induction and dispersion terms). This work employs SAPT along with an intramolecular extension (I-SAPT) to characterize various inter- and intramolecular non-covalent interactions of interest such as intramolecular hydrogen bonding in functionalized, rigid norbornane systems.

Available for download on Thursday, July 24, 2025

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