Anomalously soft dynamics of water in carbon nanotubes

Quasi-one-dimensional water encapsulated inside single-wall carbon nanotubes, here referred to as nanotube-water, was studied by neutron diffraction, inelastic and quasielastic neutron scattering. The study reveals that nanotube-water is a new state of water manifested by weak hydrogen bonds, extended intermolecular water-water distances and very large amplitude of water molecules vibrations. Molecular dynamics simulations well describe the observed spectra and give a possible nanotube- water structure in a form of a square-ice sheet wrapped into a cylinder next to the inner carbon nanotube wall and a water chain in the interior. The soft dynamics of nanotube-water arises mainly from the drastic change in hydrogen-bond connectivity of the central water-chain.