Polyacetylenes, nonlinear optics applications

As to the content of Volume 25, the Editors thank the authors for their contributions, which give an interesting picture of part of the current state of the art of the quantum theory of matter From nonlinear-optical calculations, over a study of ion motion in molecular channels, a treatment of molecular integrals over Gaussian basis functions, and an investigation of soliton dynamics in franr-polyacetylene, to applications of quantum molecular similarity measures. 

K-Conjugated polymers and oligomers are organic materials with many interesting and useful properties [1, 2], Examples of this class of materials include polyacetylene, polythiophene, polypyrrole, poly(phenylenevinylene) and their derivatives. Electronic conductivity, luminescence and nonlinear optical behavior are all observed in these materials and these properties have been exploited in applications such as electroluminescent devices (polymer light-emitting devices or PLEDs), electrostatic coatings, electrochromic windows, chemical sensors and memory devices [3-9]. 

Most of the reported conjugated polymers with nonlinear optical or electrical activities are carbon-carbon conjugated systems, such as the extensively studied polyenes (e.g., polyacetylenes [15], polydiacetylenes [16,17], poly-/ -phenylenes) and heteroaromatic polymers (e.g., polypyrroles, polythiophenes, polycarbazoles, polyanilines) [18]. The synthetic methods, applications, and the structure-property relationships of these polymers have also been substantially investigated [19-21]. 

Third order NLO materials have potential applications such as optical switches, modulations and other nonlinear optical devices [189], Polydiacetylenes [190], polyacetylenes [191], poly(phenylene-vinylene)s [192] and polythiophenes [193] have large third-order nonlinear susceptibility % ranging from lO to 10 esu. 

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