Low frequency spectroscopy of liquid water using THz-time domain spectroscopy.

In this paper we present an investigation of the dielectric response of H2O(1) and D2O(1) as a function of temperature from a supercooled state to near the boiling point. The data are obtained using THz-time domain spectroscopy, and covers the frequency range from 0 1-2 THz corresponding to 3 to 66 cm(-1). Before presenting the experimental results, we give a short introduction to some of the properties of liquid water, in particular the inter- and intramolecular motions responsible for the low frequency spectra, and brief introduction to the THz-time domain technique and its application as reflection spectroscopy is given. We also address recent theoretical and experimental contributions to the ongoing discussion regarding the microscopic interpretation of the low frequency modes of liquid water. (C) 2002 Elsevier Science B.V. All rights reserved.