Spectroscopic studies of solute-solute and solute-solvent interactions in solutions containing N,N-dimethylformamide

Abstract

IR, far-IR and Raman spectra of DMF are reported for the liq. and over the whole concn. range in CCl4 soln. The data reflect important differences between the long-ranged and short-ranged behavior of the solute-solute and solute-solvent intermol. potentials. In particular, the far-IR spectrum is dominated by short-ranged interactions which vary only marginally with concn. and which are probably controlled by geometrical factors. On the other hand, the Raman and IR band shapes are drastically affected by at least 2 types of dephasing process, including resonance energy transfer and the effects of concn. fluctuations, both probably mediated through strong longer ranged dipolar interactions. Mol. tumbling motion is severely hindered in the liq. and gets faster on diln., presumably owing to the removal of intermol. correlations.