Albert, IDL and Das, Puspendu K and Ramasesha, S (1991) Second-harmonic generation and electronic structure of polymethineimines: a theoretical study. In: Chemical Physics Letters, 176 (2). pp. 217-224.
PDF
second.pdf - Published Version Restricted to Registered users only Download (595kB) | Request a copy |
Abstract
The second-harmonic-generation (SHG) coefficients and properties of low-lying electronic states in polyrnethineimines $(-CH=N-)_x$, up to x= 5 are calculated exactly within the PPP (Pariser-Parr-Pople) Hamiltonian. The $sp^2$ hybridized nitrogenatom parameters for the PPP model are taken from the literature, tested, and found to be satisfactory on pyridine, pyrazine, pyrimidine and s-triazine for which experimental optical gaps are known. The polymethineimines show an optical gapcomparable to that of polyenes and the extrapolated single-strand gap for the infinite polymer is 2.67 eV, slightly smaller than that obtained for polyacetylene. The SHG coefficients in polymethineimines arecomparable to that of the isoelectronic push-pull polyenes with moderately strong electron donors and acceptors. These molecules show a strong length dependence of the SHG coefficient which varies as $L^3^.^0^4$. These results are also valid for the mixed-stack donor-acceptor systems at half-filling.
Item Type: | Journal Article |
---|---|
Publication: | Chemical Physics Letters |
Publisher: | Elsevier |
Additional Information: | Copyright of this article belongs to Elsevier |
Department/Centre: | Division of Chemical Sciences > Solid State & Structural Chemistry Unit Division of Chemical Sciences > Inorganic & Physical Chemistry |
Date Deposited: | 26 Jun 2007 |
Last Modified: | 02 Nov 2010 11:09 |
URI: | http://eprints.iisc.ac.in/id/eprint/11266 |
Actions (login required)
View Item |