Combined effect of the linear and nonlinear dipole-dipole interactions on the vibrational spectra of van der Waals complexes in solutions

A new semiempirical approach is proposed for describing the regularities of the shift of the absorption bands in the IR spectra of ultimately ordered van der Waals complexes of I : I composition upon the gassolution phase transition. This approach is based on the analysis of the specific features revealed in the combined effect exerted by nonlinear (complex formation) and linear (solvation) dipole-dipole interactions on the change in the electrical and electro-optical parameters of the absorbing molecule in the structure of solvated complexes. It is shown that the concepts developed enable correct quantitative interpretation of a large amount of available experimental data for complexes of an HCl molecule with molecules of acetone and acetonitrile in a number of nonpolar solvents. (c) 2005 Pleiades Publishing, Inc.