1-1-2011

Dissertation

#### Degree Name

M.S. in Chemistry

#### Department

Chemistry and Biochemistry

Gregory S Tschumper

Steven R. Davis

#### Relational Format

dissertation/thesis

#### Abstract

Much like the instrumentation in an experimental lab, computational chemists use computers to solve the mathematical equations that describe the physics of electrons to understand the chemistry involved. The combination of the two main components of computational chemistry, the basis set and method, determines the cost'' (disk, memory, and CPU time) of a computation. A variety of basis sets and methods have been developed in the past century. The focus of this report is to accurately describe non-covalent interactions with the use of various quantum computational techniques. In Chapter 1 a brief discussion on the theory behind computational chemistry is discussed; along with the electronic problem. Chapter 2 reports the wide importance of non-covalent interactions and their subset, \pi-interactions, are to many biological processes. A discussion on how to achieve accurate interaction energies through the use of the additive scheme, and the importance of basis set dependence on higher-order correlation values, will be addressed in Chapter 3.

COinS