Effect of the nature of ions on the position of the absorption bands of water OH bonds in diffuse reflection spectra in the near-infrared region

The effect of the nature of anions and cations on the position of the absorption bands of free and crystallization water in inorganic salts in the near-infrared region (7400–4000 cm⁻¹) was systematically studied. It was shown experimentally that the shift of the absorption bands of free water to the high-frequency region is 100 cm⁻¹ in the region of 6900 and 62.1 cm⁻¹ in the region of 5160 cm⁻¹. It was concluded that the results on the shift of the water absorption bands in moisture-containing solid-state compounds with respect to those of pure liquid water can serve for a qualitative estimate of the bond energy of water with the substance under study and can be used to choose the wavelength for measuring the humidity of these objects and those more complicated in composition by means of near-infrared spectroscopy.