Quantum chemistry employs techniques in mathematics, physics and chemistry to understand the behavior and properties of atoms and molecular systems. As such, quantum chemistry can be employed within many fields in the biological and physical sciences. Quantum chemistry is particularly useful in the corroboration of experimental data, as well as predicting properties that cannot be obtained via experimental means. The methods and techniques used in quantum chemistry vary in terms of the level of accuracy, as well as the amount of computational cost involved. The difficulty in quantum chemistry is in finding a low computational cost method that can offer a reasonable level of chemical accuracy for the system analyzed.

Usually, lower computational cost methods take advantage of approximations, and many of these methods are used to determine structures and properties of large systems such as biological systems. The more accurate and computationally intensive methods tend to be used to obtain a detailed understanding of the properties of small molecular systems, with a small number of atoms. This dissertation takes into account hybrid methods and force fields that attempt to maintain a low computational cost, while improving the accuracy of results on bulk systems and reaction pathways.