The Research Methodology of Molecular Aggregation Science

The research of molecular aggregation science is very important, which depends not only on the single molecule but also on the molecular aggregates. Thus, to investigate the molecular aggregation science in more detail, it is essential to get plenty of information on the structure, including both single molecular structure and aggregation structure of molecular aggregates. However, as to the aggregation structure of molecular aggregates, it could change according to some external stimuli, in addition to the original aggregation status as determined during the forming process. In this chapter, we present the theoretical approaches developed so far, first to introduce some basic calculating methods for the understanding of the single molecule, molecular dimer or others, and intermolecular interactions in aggregates in theory, and then emphasize the key role of the single-crystal X-ray diffraction method for accurate aggregation structure among general characterization methods. In the last part, we demonstrate some examples of the changing aggregation structures upon different external stimuli, to present some research methodology.