X-Message-Number: 11642
Date: Thu, 29 Apr 1999 19:41:04 -0400
From: Jan Coetzee <>
Subject: supercooled liquid water

The existence of supercooled liquid water at
150 K

R. SCOTT SMITH AND BRUCE D. KAY

Supercooled water may offer clues to the anomalous properties of its
normal liquid state. The supercooled state also shows anomalous
thermodynamic and transport properties at low temperatures. Although
there are several theoretical explanations for this behaviour, no
consensus has emerged. Some theories preclude the existence of the
supercooled liquid below an apparent thermodynamic singularity at
228 K (refs 2, 7, 9); others are consistent with a continuous region of
metastability from the melting point at 273 K to the glass transition
temperature at 136 K (refs 6, 8, 13). But the data needed to distinguish

between these possibilities have not yet been forthcoming. Here we
determine the diffusivity of amorphous ice by studying isotope
intermixing in films less than 500 nanometres thick. The magnitude and
temperature dependence of the diffusivity is consistent with the idea
that the amorphous solid water melts into a deeply metastable extension
of normal liquid water before crystallizing at 160 K. This argues
against the idea of a singularity in the supercooled regime at ambient
pressure.

Nature 398, 788 - 791 (1999)   Macmillan Publishers Ltd.

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