The Raman Spectrum of Gypsum

In an investigation of the Raman spectra of some ionized substances in aqueous solution, it was found [1] that the frequency shift given by a solution of potassium carbonate was in fairly close agreement with the strongest shift given by calcite. Data for such a comparison in other cases do not appear to exist, for change of frequency on scattering has been measured for only a few crystalline substances. In addition to calcite [2,3,5], these are quartz [2,3,4,5], ice [5], and topaz [6]. No modified frequencies were found in the light scattered by halite [2], NaCl, fluorite [5], CaF2, or by the salts [7] LiF and NaF. In the present paper are described the results of measurements on gypsum, CaSO4•2H20, and a comparison of these with data on ammonium sulfate solution.