Mechanical instability in ice I h. A mechanism for pressure-induced amorphization

Abstract

The phenomenon of pressure‐induced crystalline →amorphous phase transformation in ice I_h has been studied with constant‐pressure molecular dynamics calculations. It was found that although the temperature dependency of the transformation pressure resembles that of the extrapolated melting curve, the actual mechanism is due to a mechanical instability in the water framework. The elastic moduli calculated at the transition show a violation of Born criteria for mechanical stability.