Anomalous Dispersion of ϐ-Carotene Solutions*

Abstract

Refractive indices of liquids were determined by measuring reflectance at a glass-liquid interface, measuring transmittance of the liquids, and calculating their relative refractive indices from a Fresnel reflection equation of Simon. The refractive index of the glass was measured independently and used to calculate n values of the liquids relative to vacuum. The spectral region investigated, 400–589 mµ, includes four absorption bands of β-carotene. Dispersion curves of two solution-solvent pairs were measured. The differences, Δnsolute=nsolution-nsolvent=ƒ(λ), were compared with the predictions of quantum dispersion equations of Davydov.