Lecture
This lecture explores the packing patterns for electron-rich systems, such as parallel-displaced and T-shaped interactions, as well as the combination of dispersive and quadrupolar interactions. It delves into the formation of excitonic coupling in dimers, leading to a stabilisation of the excited state and a splitting effect. The spectral signatures of H and J aggregates are discussed, highlighting the shifts in absorption and emission bands. The concept of Davydov splitting in the general case of excitonic coupling is also explained, along with the spectroscopic aggregates and the formation of neutral solitons in poly(acetylene).