VIBRATIONAL DYNAMICS OF WATER CONFINED IN METAL OXIDES AND MINERALS STUDIED WITH NEUTRON SPECTROSCOPY

Water plays very important role in natural and industrial systems and strongly influences on their physical properties. It exists in different forms as bulk (more than 20 crystalline phases and at least 3 amorphous states of ice are known) and confined states, on surfaces and interfaces of nanoparticles, in crystal lattice of minerals and in porous materials (fullerenes, carbon nanotubes, MOFs, MXenes, etc.). The confined water shows varying degrees of deviation from bulk water structure and dynamics, and inelastic neutron scattering (INS) is the preferred method to study these properties. We will show examples of INS results on investigations the structure and vibrational density of states of water on metal oxide nanoparticles (SnO2, TiO2, Al2O3, CuO, Fe2O3, CoO, Co3O4, etc.), which gave us details of water dynamics dependence on particle size and hydration level. The unusual low-temperature liquid-like dynamics and water quantum tunneling in carbon nanotubes and minerals hemimorphite, beryl and bassanite will be also presented and discussed based on INS experiments and computer simulations.