Bond Ellipticity Alternation: An Accurate Descriptor of the Nonlinear Optical Properties of π-Conjugated Chromophores

Thiago O. Lopes, Daniel F.Scalabrini Machado, Chad Risko, Jean Luc Brédas, Heibbe C.B. De Oliveira

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Well-defined structure-property relationships offer a conceptual basis to afford a priori design principles to develop novel π-conjugated molecular and polymer materials for nonlinear optical (NLO) applications. Here, we introduce the bond ellipticity alternation (BEA) as a robust parameter to assess the NLO characteristics of organic chromophores and illustrate its effectiveness in the case of streptocyanines. BEA is based on the symmetry of the electron density, a physical observable that can be determined from experimental X-ray electron densities or from quantum-chemical calculations. Through comparisons to the well-established bond-length alternation and π-bond order alternation parameters, we demonstrate the generality of BEA to foreshadow NLO characteristics and underline that, in the case of large electric fields, BEA is a more reliable descriptor. Hence, this study introduces BEA as a prominent descriptor of organic chromophores of interest for NLO applications.

Original languageEnglish
Pages (from-to)1377-1383
Number of pages7
JournalJournal of Physical Chemistry Letters
Issue number6
StatePublished - Mar 15 2018

Bibliographical note

Funding Information:
The work at University of Brasiliá was funded by Conselho Nacional de Desenvolvimento Cientifí co e Tecnológico (CNPq) and Coordenaca̧ õ de Aperfeico̧ amento Pessoal de Niveĺ Superior (CAPES). The work at the University of Kentucky was supported in part by start-up funds provided to C.R. by University of Kentucky Vice President for Research. The work at Georgia Tech was supported by the Georgia Research Alliance. We are grateful to Dr. Veaceslav Coropceanu, Dr. Rebecca Gieseking, and Dr. Valter Henrique Carvalho-Silva for stimulating discussions.

Publisher Copyright:
© 2018 American Chemical Society.

ASJC Scopus subject areas

  • Materials Science (all)
  • Physical and Theoretical Chemistry


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