Formation of gas hydrate during crystallization of ethane-saturated amorphous ice.

Layers of ethane-saturated amorphous ice were prepared by depositing molecular beams of water and gas on a substrate cooled with liquid nitrogen. The heating of the layers was accompanied by vitrification (softening) followed by spontaneous crystallization. Crystallization of condensates under the conditions of deep metastability proceeded with gas hydrate formation. The vitrification and crystallization temperatures of the condensates were determined from the changes in their dielectric properties on heating. The thermal effects of transformations were recorded by differential thermal analysis. The crystallization of the amorphous water layers was studied by electron diffraction. Formation of a metastable packing with elements of a cubic diamond-like structure was noted. [ABSTRACT FROM AUTHOR]