YO:Eu and the Mössbauer isomer shift coefficient of Eu compounds fromsimulations.

We report on a full potential density functional theory characterization of YOupon Eu doping on the two inequivalent crystallographic sites 24and 8. We analyze local structural relaxation, electronic properties and the relative stability of the two sites. The simulations are used to extract the contact charge density at the Eu nucleus.

Emergence of superconductivity in doped HO ice at high pressure.

We investigate the possibility of achieving high-temperature superconductivity in hydrides under pressure by inducing metallization of otherwise insulating phases through doping, a path previously used to render standard semiconductors superconducting at ambient pressure. Following this idea, we study HO, one of the most abundant and well-studied substances, we identify nitrogen as the most likely and promising substitution/dopant. We show that for realistic levels of doping of a few percent, the phase X of ice becomes superconducting with a critical temperature of about 60 K at 150 GPa.