Electron transfer in macromolecules: Green's function and diagrammatic techniques (continued fraction representation)

We applied special graphical technique to investigate the influence of side/end groups of macromolecules upon long range electron transfer. We show that in case of acyclic side/end groups the Green function may be cast in the form of continued fraction, similarly to the result of electron transfer in random media. The structure of continued fraction correlates exactly to the side/end graph's structure. The rules of graphical construction of Green functions (which are solutions of Schwinger–Dyson equations) are presented in concise form.