Infrared Emission Spectroscopy. I. Basic Considerations

Abstract

The basic principles behind the characterization of compounds by ir emission spectroscopy have been illustrated using surface films of silicone grease and gaseous samples. Anomalous features in the spectra are accounted for by considering the absorption of emitted radiation by less thermally excited molecules in the path to the detector. It is suggested that ir emission spectroscopy can be used easily to characterize thin layers on heated specular mirrors or hot vapors at low pressure, but care must be taken in the interpretation of results for thick layers of gases at high pressure, when the temperature of the emitter is close to that of the detector, or when molecules are to be characterized on substrates whose emissivity is high.