A simple theoretical framework is used to calculate specular reflection spectra in the vicinity of an absorption band in a solid. The energy of the reflectivity peak is shown to differ from the energy of the absorption band even at normal incidence with thick samples and with thin film samples supported on a substrate. By considering the absorption band system of solid CO, synthetic reflection spectra of the Fourth Positive System of solid CO at 45° incidence are obtained that successfully match the experimental results, including striking time-dependent changes.
R. A. H. Buxton and W. W. Duley, "Some Limitations on the Interpretation of Specular Reflection Spectra with an Application to Solid CO," Appl. Opt. 13, 1184-1192 (1974)