Clustering in supercooled water

Abstract

The specific heats and densities of supercooled water and heavy water have been measured from the respective melting points to the respective homogeneous nucleation temperatures. The calorimetric measurements indicate structural contributions to the differences between the specific heats of the liquids and the corresponding crystals. These ``structural specific heats'' are exponential functions of the supercooling. The results are interpreted in terms of Frenkel's heterophase fluctuation theory. It is concluded that, during supercooling, water molecules tend to form icelike clusters incorporating six or more monomers.