The isotope effect on dynamic compression freezing. Heavy vs. ordinary water.

The phase transition of deuterated water (heavy water – D2O) into the ice VII phase was investigated. Several methods and diagnostics were used to compare to the same transition in ordinary water (H2O). First, a thin layer of liquid was quasi-isentropically compressed through shock reverberation via plate impact, simultaneously probing the phase transition with photonic Doppler velocimetry (PDV) and mid-infrared pyrometry. Second, liquid samples were continuously compressed with a pulsed magnetic drive while being probed with PDV. In a third set of experiments, the liquid was exposed to pressure-shear loading via oblique impact and probed with transverse PDV, using the amplitude and structure of the shear wave to diagnose the phase transformation. Results suggest heavy water is less deeply supercooled before reaching a metastable limit than ordinary water, and the heavy ice transition rate is faster.