Development of Quantum Chemical Methods for Studying Intermolecular Interactions in Molecular Crystals and Organic Compounds

Polymorphism is the ability of a given organic compound to crystallise in different crystal structures. These crystal structures, i.e. polymorphs, provide numerous opportunities for industrial applications due to their distinct chemical/physical properties and simultaneously pose plenty of challenges in controlling them in the real world. This thesis develops a robust and low-cost quantum chemical method to predict the lattice energies of polymorphic molecular crystals and thus understand the driving forces in their stabilities and existences.