RAMAN-SPECTROSCOPIC INVESTIGATION OF THE DYNAMICS OF UREA-WATER COMPLEXES

The hydration of urea via hydrogen-bond formation was found to have a significant effect on the observed Raman band shapes. An analysis indi cates that, on the average, one molecule of water is carried along wit h a solute molecule during its reorientational motion (tau(R) almost-e qual-to 2.5 ps). Vibrational dephasing of the nu4 vibration tau(omega) almost-equal-to 0.2 ps) is independent of concentration and appears t o decrease slightly with increasing temperature. No evidence of urea d imer formation was detected.