Optical Properties of Natural Minerals and Other Materials in the 350-50,000 CM-1 Spectral Region.

摘要

Reflectance spectra were measured in the UV, VIS, and/or IR for several natural minerals and for several aqueous solutions of ZnCl2 and H3P04. Complex refractive indices were determined for most of these materials by applying Kramers-Kronig methods to the reflectance spectra. Powders of some of the natural minerals were pressed in to pellets in order to obtain the reflectance spectra. Gypsum was studied in the crystalline form, the powder-pellet form, and by transmittance spectra through KBr pellets containing minute quantities of gypsum. A method was developed for obtaining complex refractive indices from reflectance spectra of the pellets and transmittance spectra of the powder/KBr pellet. The best specularly reflecting pellets were formed from powders of smaller particle size and with forces of from 14 to 16 tons on the 13 mm dia circular face of the pellet. The complex refractive indices of water were also updated by applying Kramers-Kronig methods to a new composite k spectrum in order to determine the n spectrum. (Author)