Low-temperature cell for IR Fourier spectrometric investigation of hydrocarbon substances

A specialized low-temperature measuring cell with a cryogenic capillary system for infrared spectral analysis of ethanol developed by the authors is presented. The use of the created low-temperature cell is possible for further studies of the low-temperature properties of both pure ethanol and mixtures with its contents, which is currently an urgent task, and the data obtained with its help can be used for ice research. Two methods of ethanol research at low temperature are presented in comparison. In the first method proposed by the authors, a specially developed low-temperature measuring cell based on a diffuse reflection prefix of the Fourier spectrometer FSM 2203 with a cryogenic capillary system is used. This system allows you to achieve the required low-temperature regime at normal atmospheric pressure. The results of the experiment are compared with the traditional method of gas-phase condensation of the test sample under low temperature conditions at the pressure P = 1.0·10–5 Torr. Infrared spectra of low molecular weight amorphous and crystalline ethanol were obtained at a temperature of 150 K at normal atmospheric pressure and in vacuum. Comparison of experimental results confirmed the operability of the new installation. In the experiments, peaks were observed in the absorption bands from 2850 to 3000 cm–1 and from 2950 to 3100 cm–1, corresponding to the valence CH vibrations of ethanol as well as in the absorption bands from 3150 to 3400 cm–1 and from 3300 to 3500 cm–1, which corresponds to the valence vibrations of OH. The results of the study showed the prospects of the proposed method and can be useful by researchers in the field of low-temperature spectroscopy at normal pressure.