SIMPLE TOPOLOGICAL ESTIMATION OF THE FIRST ELECTRONIC HYPERPOLARIZABILITY OF POLYMETHINE COMPOUNDS

Topological characteristics of end groups of polymethine compounds have been revealed which govern the value of the first electronic hyperpolarizability and are easily obtainable in the long polymethine chain approximation. For a variety of π-conjugated organics, they are represented in a table permitting prediction of compounds with pronounced nonlinear optical properties. The theoretical estimates of β are shown to correlate well with experimentally observed values.