Chromophore Environmental Effects in Saltlike Nonlinear Optical Materials. A Computational Study of Architecture/Anion Second-Order Response Relationships in High-β Stilbazolium Self-Assembled Films

Santo Di Bella, Ignazio Fragalà, Mark A. Ratner, Tobin J. Marks

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34 Citations (Scopus)


The very large cation-anion environmental effects on second-order nonlinear optical response observed in self-assembled stilbazolium monolayer ion-exchange experiments are investigated theoretically using the ZINDO/SOS quantum chemical formalism. Ion pairs consisting of the 4'-(dimethylamino)-A-methyl-4-stilbazolium cation with chloride, iodide, and p-aminobenzenesulfonate counteranions in differing mutual orientations, are examined as models to relate calculated ion pair hyperpolarizabilities to anion-exchange-induced changes in macroscopic linear optical and nonlinear optical response. Calculated hyperpolarizabilities depend strongly on the relative cation-anion packing configuration. In accord with anion exchange experiments, enhancements of the second-order nonlinear optical response on passing from Cl- to I- and p-aminobenzenesulfonate can be related to likely displacement of the bulkier I- and p-aminobenzenesulfonate anions from more closely packed structural arrangements originally produced as a consequence of the self-assembly process.

Original languageEnglish
Pages (from-to)400-404
Number of pages5
JournalChemistry of Materials
Issue number2
Publication statusPublished - Feb 1995


ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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