A model exact calculation of SHG coefficients in polysubstituted push-pull polyenes

Albert, IDL and Das, Puspendu K and Ramasesha, S (1990) A model exact calculation of SHG coefficients in polysubstituted push-pull polyenes. In: Chemical Physics Letters, 168 (5). pp. 454-460.

PDF A_model_exact_calculation_of_SHG.pdf Restricted to Registered users only Download (578kB) | Request a copy

Abstract

We report the model exact second-harmonic generation coefficients $(\beta^{exact})$ in polysubstituted all-trans push—pull polyenes up to ten carbon atoms. The Pariser-Parr-Pople (PPP) model with standard molecular parameters has been used in the calculations. The two-state charge-transfer model in these systems is inadequate and an exact calculation is necessary to obtain reliable SHG coefficients. We find that for a fixed geometry, $\beta$ is enhanced if all the electron withdrawing substituents (pull) are successively placed from one end of the polyene chain and all the electron pushing groups (push) from the other. A twisted conformation of the polyene backbone leads to large SHG coefficients at the YAG laser frequency since the system approaches two-photon resonance. For a given chain length, the SHG coefficients increase with increase in the number of the push and pull groups.

Item Type:	Journal Article
Publication:	Chemical Physics Letters
Publisher:	Elsevier Science B.V.
Additional Information:	Copyright of this article belongs to Elsevier Science B.V.
Keywords:	SHG;push-pull polyenes;Pariser—Parr—Pople;PPP
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	19 Feb 2008
Last Modified:	19 Sep 2010 04:41
URI:	http://eprints.iisc.ac.in/id/eprint/12708

Actions (login required)

View Item