Exploring ultra-fast proton dynamics in water under a static electric field

We present an experimental investigation of the single-particle dynamics of hydrogen in liquid water and ice subject to static electric field using deep inelastic neutron scattering. The nuclear mean kinetic energy, EK, of hydrogen in liquid water at room temperature does not show sensible changes when an electric field of magnitude 105 V/m is turned on. On the contrary, the value of EK in ice at 263 K and subject to the same electric field is found to be substantially lower than the reference value for ice Ih at the similar temperature of 271 K and without electric field. This is true both if the electric field is kept on or not while the sample cools from 300 K to 263 K. Concurrent diffraction measurements performed on ice subjected to an electric field show no sizeable structural changes with respect to the expected powder-averaged ice-Ih diffraction pattern.