Infrared Emission Spectra of a Thin Film of Molten Alkali-metal Nitrates

Abstract

A hot thermocouple technique was applied to measure the emission spectra of a thin film of molten nitrates. The thickness of the sample must be less than one micro meter to obtain a reasonable spectrum. Spectra obtained for various nitrates were the sharpest of the kinds and agreed with those measured by the conventional complicated technique. The shifts of the absorbance were observed by changing the cation and these could be correlated by the Pauling's ionic radii of the cations. The correlation was similar to those reported for the molten carbonate.