Repulsion forces in vibrational spectroscopy—I. Spectral shifts in vibrational spectra of condensed media caused by repulsion forces

Repulsional contributions into spectral shifts have been expressed in terms of derivatives of atom displacements with respect to vibrational normal coordinates. Attraction and repulsion have been shown to give a comparable contribution to the overall shift. Working ability of the formulae obtained for spectral shift calculations for molecular (HCl solution in CCl 4 ) and ionic (molten lithium and rubidium nitrates) liquids is demonstrated.