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

Albert, I. D. L. ; Das, Puspendu K. ; Ramasesha, S. (1990) A model exact calculation of SHG coefficients in polysubstituted push-pull polyenes Chemical Physics Letters, 168 (5). pp. 454-460. ISSN 0009-2614

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/000926...

Related URL: http://dx.doi.org/10.1016/0009-2614(90)85143-Z

Abstract

We report the model exact second-harmonic generation coefficients (βexact) 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, β 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:Article
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ID Code:10040
Deposited On:02 Nov 2010 10:03
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