Experimental evidence of a liquid-liquid transition in interfacial waterJ.-M. Zanotti1, 2, M.-C. Bellissent-Funel1 and S.-H. Chen3
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
received 5 October 2004; accepted in final form 2 May 2005
published online 27 May 2005
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.
64.70.Ja - Liquid-liquid transitions.
61.25.Em - Molecular liquids.
61.12.Ex - Neutron scattering (including small-angle scattering).
© EDP Sciences 2005