Absorption spectra of molecules adsorbed on light-scattering media. Part 2.—Interpretation of diffuse reflectance data

Abstract

A statistical model of a densely packed assembly of coated particles whose sizes are large compared with the wavelength of light is developed. Based on a description of the optical properties of the particle surface covered with an adsorbed overlayer, the suggested model relates the diffuse reflectance of the powdered sample to the optical constants of the substrate medium and the absorption cross-section of the adsorbate. The model has been tested by calculating the molar absorption coefficients of an adsorbed dye from diffuse reflectance data and, simultaneously, by using an immersion technique.