Angewandte Chemie International Edition

Cover image for Vol. 56 Issue 39

Editor: Peter Gölitz, Deputy Editors: Neville Compton, Haymo Ross

Online ISSN: 1521-3773

Associated Title(s): Angewandte Chemie, Chemistry - A European Journal, Chemistry – An Asian Journal, ChemistryOpen, ChemPhotoChem, ChemPlusChem, Zeitschrift für Chemie

Cover Picture (Angew. Chem. Int. Ed. 5/1998)

37_05/1998The cover picture shows the microphotograph of an approximately 80 nm thick, self-organized layer of the dye 1,7-bis(dimethylamino)heptamethine perchlorate (picture diameter 600 μm, taken with horizontally polarized light in transmission; as no analyzer was employed the colors are caused by absorption). “Thin-layer aggregation” at 88°C oriented the molecules in such a way that their tilt relative to the plane of the layer changes periodically (indicated schematically at the bottom). Strong interactions between the chromophores give two mutually perpendicular transition dipole moments M+, and m. Whereas the m component always lies in the plane of the layer and yields a red color (perpendicular in the picture), the different slope of the m+, component yields a periodic color change (horizontal in the picture). More about this polariton-induced variation in the absorption wavelength of thin dye films is reported by L. Dähne et al. on p. 646 ff.

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