| Abstract
| - J-Aggregates of the amphiphilic symmetrical cyanine dye 5,5‘-6,6‘-tetrachloro-1,1‘-diethyl-3,3‘-dioctadecyl-benzimidazolocarbocyanine toluenesulfonate are formed in monolayers of the pure dye at the air−waterinterface as well as in mixtures with the coaggregates hexadecane (HD) and methyl octadecanoate (MOD),respectively, at a molar ratio of dye/coaggregate of 1:1. The monolayers have been characterized by surfacepressure−area and surface potential−area isotherms as well as reflection spectroscopy. The position ofthe J-aggregate band that is red-shifted with respect to the monomer band depends on the kind of coaggregate.This in the case of symmetrical cyanines surprising phenomenon was analyzed by applying the extendeddipole model according to the model of two-dimensional “brickstone” structure assuming that the coaggregateMOD in contrast to HD modifies chromophore packing.
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