Single Monochromator Infrared Spectrophotometers

The schematic layout of a single-monochromator infrared spectrophotometer has been duly depicted in Figure 22.2. 

Figure 22.2. Optical Diagram of a Single-Monochromator Infrared Spectrophotometer.

The infrared spectrophotometers are based on either single monochromation or double monochromation ... 

The necessary instrumentation for making dichroic measurements depends on the technique used. The most common method is to use a single polarizer and an ordinary infrared or ultraviolet spectrophotometer. The sample (thin film) is then placed in the sample beam preferably before the polarizer and generally with the stretch axis at 45° to the entrance slit of the monochromator. This inclination of the stretch axis is to minimize the effect of machine polarization. Such effects have been discussed by Makus and Shareliff (42) and Jones (28). The electric vector of the polarizer is then aligned either parallel or... 

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.

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