WEAK INTERMOLECULAR INTERACTIONS IN SIMPLE ALKANES, HALOGENS AND p ELECTRON-RICH MOLECULES

Abstract

Three types of intermolecular interactions were studied in this thesis. The neutral alkane and conjugated alkene complexes are dominated by dispersion, the dihalogen-donor complexes by electrostatic interaction and charge transfer, and the interaction between p-rich ions by electrostatic interactions.

This thesis revealed a source for electrostatic attraction, penetration effect. Such effect is not directional, and it will be significant when the intermolecular distance is greatly reduced by charge transfer or dispersion. In these cases, the nature of the complex should still be considered dispersion-dominated or charge-transfer-dominated. The understanding of dispersion was also improved from an additive point of view. Dispersion can be divided into orbital contributions, and such orbital contributions are helpful to understand equilibrium distance of complexes. It was also found that the charge transfer can induce electronic structure changes. Three diabatic states are important to describe the charge transfer complexes.