Dispersive infrared spectrometers single-beam

Figure 10.7 Schematic diagram of spectrometers and analysers in the infrared, (a) Single beam analyser containing a fixed monochromator or a filter used when a measurement at a single wavelength will suffice (b) dispersive spectrometer, double beam system. In contrast to spectrophotometers in the UV/Vis, the sample, located prior to the monochromator is permanently exposed to the full radiation of the source, knowing that the energy of the photons in this region is insufficient to break the chemical bonds and to degrade the sample (c) Fourier transform single beam model.

In order to make rapid, accurate comparisons of a sample and a reference, double-beam instruments are frequently used. Since it is essential that the two beams are as similar as possible, a single source is used and the optics arranged to pass equal intensities of the beam through the sample area and through the reference area, and then to disperse and detect them alternately. This is shown schematically in Figure 1 for an infrared spectrometer. 

A review covering instrumentation—sources of infrared radiation, slit system, dispersing elements, detectors, amplification and recording, single and double-beam and fast-scanning spectrometers, preparation and examination of samples, applications of infrared spectroscopy, and infrared spectroscopy and coal structure. 232 references. 

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