On the Unusual Thermal Conductivity of Ices at Elevated Pressures

Abstract

There are numerous forms of ice including 13 crystalline phases,1) several distinctly different amorphous solid states and various clathrate hydrates. Ten of the crystalline phases, namely, ices II, III, IV, V, VI, VII, VIII, IX, X and XII, are produced at high pressures and three, hexagonal (Ih) and cubic (Ic) ices and ice XI, are produced at ambient pressure. The amorphous forms of solid water are: (i) amorphous solid water formed by hyperquenching micron-sized droplets (HQW) and by vapor-deposition on a cold plate (ASW),1) (ii) high-density amorphous ice,2) (iii) low-density amorphous ice3) and (iv) very high-density amorphous ice.4) While all the crystalline phases of water have been unequivocally established and the similarity between ASW and HQW is reasonably well established, the distinction between the amorphous states produced at high pressures and their relation to ASW is not. One of these amorphous states is formed by subjecting ice