A new exotic phase of ice
In a challenging study combining neutron scattering experiments under extreme conditions with molecular simulations, a team from the condensed matter group in the Physics department has observed plastic Ice VII for the first time. This exotic phase, predicted over a decade ago, forms at pressures exceeding 50,000 atmospheres and temperatures above 500 K.
This newly discovered state of matter is a hybrid between a liquid and a solid: water molecules are arranged in a dense cubic lattice but retain rotational motion, much like in a liquid.
Using Quasi-Elastic Neutron Scattering (QENS) at the Institut Laue-Langevin in Grenoble, the team identified the unique jump-rotor nature of this phase. Molecular Dynamics simulations and Markov Chain analysis further revealed the intricate mechanism behind water molecule reorientation.
This discovery has major implications for planetary science, as the plasticity of Ice VII influences the thermal and mechanical properties of icy planetary interiors. It may help explain key differences in the evolution of Jupiter’s moons, Ganymede and Callisto, while offering new insights into the formation of water-rich planets.
Authors: Maria Rescigno, Alberto Toffano, Umbertoluca Ranieri, Leon Andriambariarijaona, Richard Gaal, Stefan Klotz, Michael Marek Koza, Jacques Ollivier, Fausto Martelli, John Russo, Francesco Sciortino, Jose Teixeira & Livia Eleonora Bove