Quantum-confinement effects on the ordering of the lowest-lying excited states in conjugated chains

Shuai, Z and Bredas, JL and Pati, SK and Ramasesha, S (1997) Quantum-confinement effects on the ordering of the lowest-lying excited states in conjugated chains. In: Physical Review B: Condensed Matter, 56 (15). pp. 9298-9301.

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Abstract

The symmetrized density-matrix renormalization-group approach is applied within the extended Hubbard-Peierls model (with parameters U/t, V/t, and bond alternation delta) to study the ordering of the lowest one-photon (1(1)B(u)(-)) and two-photon (2(1)A(g)(+)) states in one-dimensional conjugated systems with chain lengths N up to N = 80 sites. Three different types of crossovers are studied, as a function of U/t, delta, and N. The ''U crossover'' emphasizes the larger ionic character of the 2A(g) state compared to the lowest triplet excitation. The ''delta crossover'' shows strong dependence on both N and U/t. the ''N crossover'' illustrates the more localized nature of the 2A(g) excitation relative to the 1B(u) excitation at intermediate correlation strengths.

Item Type:	Journal Article
Publication:	Physical Review B: Condensed Matter
Publisher:	The American Physical Society
Additional Information:	Copyright of this article belongs to The American Physical Society.
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	30 Jun 2011 13:49
Last Modified:	30 Jun 2011 13:49
URI:	http://eprints.iisc.ac.in/id/eprint/38376

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