Experimental evidence of a liquid-liquid transition in interfacial water

¹ Laboratoire Léon Brillouin (CEA-CNRS), CEA Saclay 91191 Gif/Yvette cedex, France
² Intense Pulsed Neutron Source, Argonne National Laboratory Argonne, IL 60439, USA
³ Department of Nuclear Engineering, 24-209, MIT Cambridge, MA 02139, USA

Corresponding author: jmzanotti@cea.fr

Received: 5 October 2004
Accepted: 2 May 2005

Abstract

At ambient pressure, bulk liquid water shows an anomalous increase of thermodynamic quantities and apparent divergences of dynamic properties on approaching a temperature of 228. At normal pressure, supercooled water spontaneously freezes below the homogeneous nucleation temperature, . Upon heating, the two forms of Amorphous Solid Water (ASW), LDA (Low Density Amorphous Ice) and HDA (High Density Amorphous Ice), crystallise above . As a consequence, up to now no experiment has been able to explore the properties of liquid water in this very interesting temperature range between 150 and 235. We present nanosecond-time-scale measurements of local rotational and translational dynamics of interfacial, non-crystalline, water from 77 to 280. These experimental dynamic results are combined with calorimetric and diffraction data to show that after exhibiting a glass transition at 165, interfacial water experiences a first-order liquid-liquid transition at 240 from a low-density to a high-density liquid. This is the first direct evidence of the existence of a liquid-liquid transition involving water.