Hydrogen diffusion in ice XVII

The aim of this proposal is to study the diffusion properties of hydrogen molecules in a recently discovered, highly porous form of ice, named ice XVII, at different values of temperatures and hydrogen filling, through Quasi-Elastic Neutron Scattering (QENS). Owing to the strong incoherent character of the H2 molecule signal, we will be able to efficiently measure the diffusion properties of the guest species within the fully deuterated ice XVII skeleton, which presents an intriguing helicoidal channel structure, with a channel diameter of about 6.10 Å. We expect the hydrogen diffusion here to be faster than that in the channels of normal ice Ih. In addition, we also expect to find experimental evidence of an inherently one-dimensional diffusion in this system, which, for a powder sample, shows up as a non-Lorentzian line-shape in the QENS spectrum.