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Proceedings Paper

Polymer fluorescence: even-parity states, alternation, and heteroatoms
Author(s): Zoltan G. Soos; Douglas S. Galvao; Shahab Etemad
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Paper Abstract

Polymer fluorescence indicates a lowest singlet excitation S1 of odd parity, while an even-parity S1 favors radiationless decay. The optical gap Eg defines the lowest odd-parity singlet, 11Bu, and the two-photon gap Ea fixes the 21Ag state. The 1B/2A ordering of conjugated polymers reflects different single-particle gaps, 4t(delta) for alternating chains, at nearly constant correlations. Topological and heteroatom contributions to the effective alternation of poly-p- phenylenevinylenes and polythiophenes are discussed, polymer spectra is analyzed in terms of molecular (pi) -electron theory. Even-parity states at Ea and biexcitons derived from two- electron excitation across Eg indicate intermediate correlations and alternations, thereby limiting the accuracy of band, strong-correlation, and large-(delta) descriptions. Correlated states in the dimer limit illustrate the 2A/1B crossover of Hubbard or excitonic systems.

Paper Details

Date Published: 2 June 1994
PDF: 12 pages
Proc. SPIE 2144, Advanced Photonics Materials for Information Technology, (2 June 1994); doi: 10.1117/12.177222
Show Author Affiliations
Zoltan G. Soos, Princeton Univ. (United States)
Douglas S. Galvao, Bell Communications Research and Univ. Estadual de Campinas (Brazil)
Shahab Etemad, Bell Communications Research (United States)

Published in SPIE Proceedings Vol. 2144:
Advanced Photonics Materials for Information Technology
Shahab Etemad, Editor(s)

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