Mohanalingam, K and Das, Puspendu Kumar and Rajappa, S (1992) Second harmonic generation in some donor-acceptor ethylenes—I. In: Spectrochimica Acta Part A: Molecular Spectroscopy, 48 (11-12). pp. 1647-1656.
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We report the absorption spectra, oscillator strengths, ground state and excited state dipole moments, and molecular second order polarizability coefficients (βCT) due to donor—acceptor charge transfer in four trisubstituted ethylenes, namely 1,1-bisdimethylamino-2-nitroethylene, 1,1-bispyrolidino-2-nitroethylene, 1,1-bispiperidino-2-nitroethylene and 1,1-bismorpholino-2-nitroethylene. The results are compared with that of trans-N,N-dimethylamino-nitroethylene, which has a large βCT. The powder second harmonic generation (SHG) intensity of all these molecules is also measured and only 1,1-bispiperidino-2-nitroethylene is found to possess an efficiency of 20% of that of urea under the same conditions. The SHG efficiency of this compound and deficiency in the other molecules in the powdered state is discussed in terms of their arrangements in the unit cell. The crystal structure of the active molecule is also presented and the structure—property relationship is critically examined in all these molecules.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to Elsevier science.|
|Department/Centre:||Division of Chemical Sciences > Inorganic & Physical Chemistry|
|Date Deposited:||04 Jan 2011 08:50|
|Last Modified:||04 Jan 2011 08:50|
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