Electron-Phonon Coupling and Intramolecular Charge Transfer from their Vibrational Spectra of Potential NLO Chromophores of Stilbene Derivatives

• Published in: Perspectives in Vibrational Spectroscopy (AIP Conference Proceedings Volume 1075) Vol. 1075; pp. 85 - 88
• Main Authors: Vijayakumar, T, Joe, I Hubert, Nair, C P Reghunadhan, Jayakumar, V S
• Format: Journal Article
• Language: English
• Published: 01.01.2008
• ISBN: 9780735406063; 0735406065
• ISSN: 0094-243X
• DOI: 10.1063/1.3046235

Conjugated organic molecules with large optical non-linearities have become the focus of current research in view of their potential applications, in various photonic technologies. Dipolar push-pull Organic chromophores that exhibit extended p-conjugation, in particular, show enhanced second order NLO properties. Among them, NLO-phores constituted by stilbene derivatives bearing electron-donor and electron-acceptor groups at the end position of the p-conjugated system have been subject of great research efforts. The second order NLO properties seem to be related with the existence of a large intramolecular charge transfer at relatively low energy values. The study of the vibrational spectra is an effective tool to get information about the structure-NLO property correlations of the push-pull molecules. This work deals with the electron-phonon coupling and intramolecular charge transfer that considerably contributes to the linear electro-optic effect of the high efficiency push-pull NLO chromophores 4-[N, N-Dimethylamino]-4'-N'-Methyl Stilbazolium Tosylate (DAST) and 4-[N, N-Dimethylamino]-4'-Nitro Stilbene (DANS) from their vibrational spectra.