Raman Measurements on Thin Polymer Films and Organic Monolayers

Abstract

Resonant and nonresonant Raman scattering measurements have been obtained from very thin (27 Å to 1 μ) films of long chain organic molecules and polymers using multilayered integrated optics. The increased optical field intensity within the film together with an increase in scattering volume enable high signal/noise spectra to be obtained. Investigation of a single cyanine dye monolayer using the Resonance Raman effect has revealed frequency shifts of the quinoline in plane C—C and C—N stretching modes at 1392 and 1366 cm⁻¹ resulting from intermolecular adhesive forces at the film-Corning glass interface. Bandwidth broadening of these modes indicates a distribution of chromophore environments at the glass surface possibly reflecting the heterogeneity of surface binding sites.