Scaling law for second-order hyperpolarizability in poly(triacetylene) molecular wires
1999; Optica Publishing Group; Volume: 24; Issue: 22 Linguagem: Inglês
10.1364/ol.24.001599
ISSN1539-4794
AutoresU. Gubler, Ch. Bosshard, Peter Günter, Marina Yu. Balakina, Jérôme Cornil, Jean‐Luc Brédas, Rainer E. Martin, François Diederich,
Tópico(s)Fullerene Chemistry and Applications
ResumoPoly(triacetylenes) are rodlike molecules with electrons delocalized over a one-dimensional path. We show that they exhibit a power-law dependence of the second-order hyperpolarizability gamma on the monomer unit n for short molecules and a smooth saturation toward a linear increase in longer molecules. The power law of gamma?n(a) with a approximately 2.5 from dengenerate four-wave mixing and third-harmonic generation measurements is in good agreement with quantum-chemical calculations. The critical conjugation length for saturation in the three cases is shown to be approximately 60 carbon-carbon bonds, which indicates the upper boundary for the electron delocalization in such a one-dimensional molecular wire.
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