Molecular Orbital Calculations of Nonlinear Optical Parameters for Test Molecules of a Highly Amphoteric and Polar Molecule (HAPM)

• Published in: Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals Vol. 355; no. 1; pp. 319 - 329
• Main Authors: Sato, Naoki, Sakuma, Taro, Yoshida, Hiroyuki, Silinsh, Edgar A., Jurgis, Andrejs J.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis Group 01.01.2001
• Subjects: amphoteric molecule; electronic delocalization; hyperpolarizability; intramolecular charge transfer; second harmonic generation
• ISSN: 1058-725X
• DOI: 10.1080/10587250108023668

Semiempirical molecular orbital calculations of 2-(4-dicyanomethylenecyclohexa-2,5-dienylidene)-4,5-ethylenedithio-1,3-dithiole and its analogues, as test molecules towards a highly amphoteric and polar molecule (HAPM) designed on the basis of combination of electron-donating and accepting molecular segments with a pseudo-delocalized electron system were carried out to estimate several molecular parameters, in particular, those regarding the second-order optical nonlinearity, in order to examine a difference between the proposed molecular design and the conventional one for the ,push-pull' type of molecules. Large values of the first molecular hyperpolarizability are obtained for the present molecules, however, it is turned out that the trade-off relation between hyperpolarizability and transparency of a material is also concerned with these materials. This indicates that the proposed molecular design toward HAPM is unique and can be useful to bring about novel materials with remarkable properties.