KINETICS OF CRYSTALLIZING D2O WATER NEAR 50 K BY FOURIER-TRANSFORM INFRARED-SPECTROSCOPY AND A COMPARISON WITH THE CORRESPONDING CALORIMETRIC STUDIES ON H2O WATER

Crystallization kinetics of hyperquenched D2O liquid has been studied by Fourier transform infrared spectroscopy by determining the irreversible change in the spectra of stretching vibrations of the decoupled OH oscillator in ≈12 mol % HOD in D2O. The kinetics follows an almost exponential behavior with time. The exponent to the crystallization time, n, increases from its value of 1.0 at 152 K to 1.2 at 147 K and its value is slightly lower than that of H2O. The combined results of H 2O and D2O indicate that temperature rather than the mass of the molecules determines n. Interpretation of n in terms of the morphology of grains formed seems inconsistent in view of the observed temperature effect. It is suggested that an alternative interpretation of n in terms of distribution of diffusion times, or time independent activation energy (barrier height to crystallization), is more appropriate. Calorimetric measurements for the crystallization of H2O yield results consistent with those from infrared spectroscopic study. © 1995 American Institute of Physics.