The polarizability and the second hyperpolarizability of tetrakis(phenylethynyl)ethene and several of its lithiated derivatives

The polarizability (alpha) and the second hyperpolarizability (gamma) of te trakis(phenylethynyl)ethene (TPEE) are compared and analyzed in connection with the properties (alpha, gamma) of a series of selected/designed molecul es having different conjugation patterns. Several Lithiated derivatives of TPEE are designed and shown to have very enhanced second hyperpolarizabilit ies; for example, one of the lithiated TPEE has a 1.6 x 10(3) times larger second hyperpolarizability than that of benzene. The potential of the propo sed derivatives for applications in photonics is noted. The polarizabilitie s and the hyperpolarizabilities of the considered molecules have been compu ted employing the PM3 method which has been proven to be adequate for the p resent comparative study. (C) 1999 John Wiley & Sons, Inc.