Bond alternation in the infinite polyene: Effect of long-range Coulomb interactions

S. Mazumdar, D. K. Campbell

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


We investigate the effects of long-range Coulomb interactions on bond and site dimerizations in a one-dimensional half-filled band. It is shown that the ground state broken symmetry is determined by two sharp inequalities involving the Coulomb parameters. Broken symmetry with periodicity 2kF is guaranteed only if the first inequality (downward convexity of the intersite potential) is obeyed, while the second inequality gives the phase boundary between the bond-dimerized and site-dimerized phases. Application of these inequalities to the Pariser-Parr-Pople model for linear polyenes shows that the infinite polyene has enhanced bond alternation for both Ohno and Mataga-Nishimoto parameterizations of the intersite Coulomb terms. The possible role of distant neighbour interactions in photogeneration experiments is discussed.

Original languageEnglish (US)
Pages (from-to)163-172
Number of pages10
JournalSynthetic Metals
Issue number1-3
StatePublished - Jan 1986

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry


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