On the influence of their state in solution on the absorption spectra of dissolved dyes

Abstract

In a previous investigation of the absorption spectra and sensitising properties of some isocyanine dyes,* the influence of the solvent was examined and it was found that the absorption maximum was shifted toward the red as the refractive index of the solvent increased. This is in accordance with Kundt’s law. The absorption in water, however, differs markedly from that in organic solvents. In the latter the spectrum consists of a prominent band in the orange and a half-shade nearer the blue. In water this half-shade has become a separate band comparable in intensity with the orange. Absorption curves in alcohol and water are shown. It is convenient to term the band near the red the β-(organic) band, the one nearer the blue the α-(water) band. It appeared desirable to investigate this difference further.