Concerning the Absorption and Reflection Spectra of Calcite in the Infrared

Abstract

The reflection and absorption bands of calcite at 6.6-7.4μ have been studied with an echelette grating spectrometer of high resolving power, empolying the resonance radiometer. A great deal of hitherto unobserved fine structure has been detected. It is to be noted: (1) that the maxima of the envelopes of the absorption and reflection bands differ widely in wave-length, as has been previously reported in the literature; (2) that within the bands, there is good agreement as to wave-length between the absorption and reflection lines. Possible explanations of this fine structure are offered, including that of combinations of reststrahlen and near infrared frequencies.