Electronic spectral intensities in binary solvent mixtures

A systematic study on the intensities of n-π* band of benzophenone in various binary solvent mixtures has been carried out with a view to investigate the behaviour of electronic band intensities in different environments. Possibilities of relating band intensities to equilibrium constants of dipole-dipole and other complexes, solvent compositions and dielectric constants of binary solvent mixtures have been examined. It is found that in all the cases plots of Cp/ε{lunate} vs. Cp and (D-D0)/ε{lunate} vs. (D-D0)-where ε{lunate} is the extinction coefficient of n-π* transition of benzophenone in a solvent mixture containing Cp moles of perturbing solvent, D is the dielectric constant of the solvent mixture and D0 the dielectric constant of the assumed nonperturbing solvent-were very good straight lines. Similar behaviour was also shown by the infrared band intensity data given in the literature. © 1973.