Slow dynamics of interfacial water

The highlights of our recent high-resolution quasi-elastic incoherent neutron: scattering studies of the translational dynamics of water molecules contained in the micropores of Vycor glass and on the surface of a deuterated protein are summarized. The incoherent quasi-elastic spectra from the confined H2O are first analyzed by a confined diffusion model to obtain the elastic incoherent structure factor (EISF), the short-time self-diffusion constant (D), and the probability per unit time for a jump (1/(tau 0)) as functions of the surface coverage and temperature. The effect of the confinement on the slowing down of the translational motion is discussed. An alternative interpretation of the slow dynamics based on a molecular mechanism of a cage effect and an approach to the kinetic glass transition is put forth.