Ab Initio Study of the Influence of Molecular Structure on the Static Polarizability of Conjugated Chains

Some of the future applications in optical communication systems probably be based on the large second- and third-order nonlinear optical resoonses observed in several organic molecules and polymers[1]. In these compounds, large values of α,β and γ (respectively the polarizability, first and second-order hyperpolarizability tensors) which corresoond to higher linear and/or nonlinear responses of a medium, are found associated with the existence of conjugated π-systems. Finding the structural and constitutive attributes of the most responsive compounds, e.g. by quantum mechanical calculations, is in itself a research of fundamental and applied interest.