Infrared- and Visible-range Absorption Spectra of Dyes in Aggregated Form Adsorbed by Silver Bromidet

Abstract

The present authors have succeeded in the observation of the effect of aggregate formation on infrared absorption spectra of dye molecules (2, 2'-quinocyanine) adsorbed on silver bromide, by use of an infrared spectrophotometer with a diffusive reflection attachment without pressing or crashing the dyed silver bromide powder. The infrared absorption spectrum of the adsorbed dye in J-aggregated form has been found to be identical to that of the dye crystal. This result suggests the physical adsorption of the dye on silver bromide. Small difference in absorption peaks around 800 cm-' between the adsorbed dyes in molecular state and in Jaggregated state has been attributed to the presence of physical interaction between dye molecules. † Studies on Mechanism of Photographic Sensitivity.