Influence of intermolecular distance on optical property in polydiacetylene crystalline films

Abstract

Optical absorption spectrum of polydiacetylene (PDA) crystalline films shifts toward higher energies as irregularity in molecular ordering is increased. We view this behavior in terms of the reduced overlap of conjugated π-electron wave function among one-dimensional PDA molecular wires. This point is further discussed by using the Kronig–Penney model, in which the influence of irregularity in molecular ordering is assessed in terms of a change in the intermolecular distance which in turn shifts the fundamental absorption edge.

Optical and electronic properties of neutral and charged oligodiacetylene clustersPresented at the LANMAT 2001 Conference on the Interaction of Laser Radiation with Matter at Nanoscopic Scales: From Single Molecule Spectroscopy to Materials Processing, Venice, 3–6 October, 2001.

“…3,4 It is well known that the properties of molecular systems can change drastically on going from isolated molecules to clusters or bulk materials. [5][6][7] The theoretical study of the effects of clusters or films on the electronic and optical properties of conjugated systems could suggest strategies for the synthesis and/or the assembly of molecules which would allow one to preserve or to increase properties of technological interest. Nonetheless most of the theoretical work on clusters is focused on small molecules, 8,9 while only a few theoretical studies have been dedicated to conjugated systems, and usually these do not consider more than a neutral dimer structure.…”