Which is the effective time scale of the fast Debye relaxation process in water?

Two reorientational relaxation processes have been suggested to occur in liquid water. However, while there is general agreement on the value of the slow Debye relaxation time constant, a question arises on the effective time scale of the fast relaxation process, that has been reported to occur in the 0.2-1 ps range at room temperature. It is shown here that, the combined analysis of the available microwave and far-infrared dielectric spectroscopy literature data, suggests the existence of three relaxation processes in H2O(1). Such interpretation is consistent with the most recent literature on the rotational dynamics of such liquid. (C) 2007 Elsevier B.V. All rights reserved.