Strategies to obtain highly ordered deuterated ices presented on the example of ice XIV

Abstract

Abstract Highly ordered deuterated ices have been inaccessible in the past due to the unfavorable slow kinetics. On the example of ice XIV, we introduce three strategies in this study that enhance the degree of order compared with the literature approach of slow cooling. These strategies involve (i) isothermal annealing under pressure, (ii) aging at 77 K, and (iii) introducing isotope defects in addition to the previously used strategy of acid/base doping. We employ the techniques of calorimetry, dielectric relaxation spectroscopy, volumetry, and powder X-ray diffraction to investigate orientational order on the example of the ice XIV–XII order–disorder pair. These strategies allow us to access highly ordered D2O-ice XIV, tripling the degree of order reached in previous work. These strategies can be employed for other ice phases and hold the potential for future discoveries of new forms of ice with distinct material properties.