Computational investigations of some molecular properties, their perturbation by external electric fields, and their use in quantitative structure-to-activity relationships

Abstract

This thesis consists of three quantum chemical investigations. The first investigates the changes in the chemical bond in strong electric fields, a necessary first step for understanding the behaviour of a substrates or drugs in enzyme active sites where such fields are ubiquitous. The second study traces the atomic origins of the sharp peaks in the dipole moment near the transition states of chemical laser reactions. The Quantum Theory of Atoms in Molecules is used to decompose the dipole moment surfaces into atomic contributions. Since these peaks can be exploited in the laser control, this knowledge adds another layer of control on tuneable reactions through the choice of reactants maximizing the laser-molecule interaction. The last study outlines a quantitative structure-to-activity study relating the observed anti-carcinogenic and anti-inflammatory activities of 150 molecules to calculated electronic properties, reducing the cost, time, and effort in the design of anticancer and anti-inflammatory drugs.