Faculty Advisor

Dr. Graham Griffin


Point dipole and line dipole coupling approximations are two methods for approximating the transition dipole coupling between two conjugated organic molecules. Transition dipole couplings are an important factor in determining energy transfer between two non-covalently-bonded molecules. Transition dipole couplings were mathematically calculated by two methods, applying the point dipole and line dipole approximations. The calculations were implemented using Octave, an open source computer programming language. Using this tool, software was created to efficiently analyze the differences between transition dipoles calculated using the two methods, for a variety of relative orientations of two model conjugated organic molecules. Custom-built software was created to model two polymers with varying relative orientation within three-dimensional space. As illustrative examples, we analyzed the results of polymers that were parallel, and at a forty-five degree tilt.We also analyzed the dependence of the coupling of two parallel polymers on a key parameter of the line-dipole model, the number of sub-units over which the transition was distributed. We compare the point dipole and line dipole couplings, finding that the line-dipole coupling method generally produces smaller couplings.