The self-diffusion coefficient of water has been measured by the steady-gradient spin-echo method at pressures up to 2380 bar and temperatures between 2 and −20°C in the stable liquid range using both strengthened glass and beryllium–copper pressure vessels. At low temperatures and high pressures the diffusion coefficient becomes almost independent of pressure. However, a rapid increase in DH2O with the first kilobar of applied pressure is inferred for the supercooled liquid from the relation of the new data to the 1 atm pressure diffusivity of supercooled water. The observations may be correlated with the high pressure low temperature thermodynamic properties of water in a manner consistent with the Adam–Gibbs entropy theory of liquid transport processes.

Neutron-diffraction spectra have been recorded at 80°K for polycrystalline D2O cubic ice (Ic) obtained by the transformation of the high-pressure ices II, V, and IX. Spectral differences were found among these ice Ic preparations, principally in the degree of asymmetry of the (111) cubic reflection and in the extent of line broadening. The cubic (111) peak of greatest symmetry was obtained by the transformation of ice II. The line broadening appears to be associated with the small particle sizes of the ice Ic produced by the transformation of the high-pressure ices under controlled-temperature conditions. Peak centroids for scattering angles between 15° and 62° give a weighted cubic lattice parameter, a0 = 6.353 ± 0.001 Å. As revealed by an analysis of neutron-diffraction line intensities, attempts to induce the formation of ice Ic by the quenching of aqueous ferrous chloride or potassium chloride solutions in liquid nitrogen were unsuccessful.

Acoustic transients can be thermally generated in water by pulsed microwave energy. The peak pressure level of these transients, measured within the audible frequency band as a function of the microwave pulse parameters, is adequate to explain the "clicks" heard by people exposed to microwave radiation.

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