Strain Relief during Ice Growth on a Hexagonal Template

Formation of hexagonal and cubic ice during low-temperature growth.

From our daily life we are familiar with hexagonal ice, but at very low temperature ice can exist in a different structure--that of cubic ice. Seeking to unravel the enigmatic relationship between these two low-pressure phases, we examined their formation on a Pt(111) substrate at low temperatures with scanning tunneling microscopy and atomic force microscopy. After completion of the one-molecu...

Freezing Properties of Disaccharide Solutions: Inhibition of Hexagonal Ice Crystal Growth and Formation of Cubic Ice

Proton ordering in cubic ice and hexagonal ice; a potential new ice phase--XIc.

Ordinary water ice forms under ambient conditions and has two polytypes, hexagonal ice (Ih) and cubic ice (Ic). From a careful comparison of proton ordering arrangements in Ih and Ic using periodic density functional theory (DFT) and diffusion Monte Carlo (DMC) approaches, we find that the most stable arrangement of water molecules in cubic ice is isoenergetic with that of the proton ordered fo...

Temperature-induced amorphisation of hexagonal ice.

We systematically studied the competition between polymorphic transformations and amorphisation of hexagonal ice on isobaric heating from 77 K to 155-170 K at pressures between 0.50 and 1.00 GPa. This competition is analysed here systematically by in situ dilatometry and ex situ X-ray diffraction and calorimetry. Volume vs. temperature curves were analysed using a novel fitting approach in orde...

Permeation of Light Gases through Hexagonal Ice

Gas separation using porous solids have attracted great attention due to their energetic applications. There is an enormous economic and environmental interest in the development of improved technologies for relevant processes, such as H2 production, CO2 separation or O2 and N2 purification from air. New materials are needed for achieving major improvements. Crystalline materials, displaying un...