Spectroscopic study of the structure of Rodamine 6G associates in ethanol solutions

The concentration dependence of the absorption spectra of ethanol solutions of rhodamine 6G at low temperatures is studied. It is established that under these conditions two types of associates may form. Associates with a general solvate shell typically manifest a new band in the absorption spectrum which appears as a consequence of a shift of the electronic levels of monomer molecules created by the field of nearby molecules. Associates consisting of molecules with individual solvate shells have lesser absorptivity than the monomer molecules. Molecules are joined into such associates as a consequence of dispersion interaction.