Spectroscopic Study of Concentration Fluctuation and Intermolecular Interaction in Liquid

The band widths of the infrared absorption spectra were observed for binary solutions of methyl iodide, methyl cyanide, chloroform, and carbon disulfide. The observed bands are: the v1 fundamental of chloroform in carbon disulfide and in carbon tetrachloride; the v2 fundamental of methyl iodide in methyl cyanide, nitromethane, benzene, carbon disulfide, and carbon tetrachloride; the 2v2 band of methyl iodide in methyl cyanide, and the v8 and 2v8 bands of methyl cyanide in methyl iodide. The concentration dependence of a band width was explained in terms of the concentration fluctuation. The theory was compared with the observed band widths, together with the light-scattering data. A fluctuation volume was related with the intermolecular interactions in these binary solutions.