Ionization Energy of Singly Adsorbed Dye Molecules*

Abstract

AbstractThe ionization energy of cationic cyanine dyes adsorbed on glasses is only slightly dependent on the density of the adsorbate on the substrate. At very low densities, the range of ionization energies of adsorbed molecules narrows markedly. A model for a cyanine cation adsorbed on glass is suggested which has elements in common with that of Nelson and Selsby for a cation adsorbed on an ionic crystal in that it achieves the excess of negative charge in the vicinity of the ion required to give ionization energies in the range observed. Analysis shows that there ? profoundly statistical elements intrinsic to the ionization of adsorbed dyes which make it unrealistic to attempt to specify the energy exactly.