Low-frequency dynamics in confined water: a comparative analysis by Raman and inelastic neutron scattering

In this paper we report the results of a study of low-frequency vibrational dynamics and electron-vibration coupling in water in the bulk and confined state, at different hydration percentages. The simultaneous use of both Raman spectroscopy and time-of-flight inelastic neutron scattering allowed us to determine the respective vibrational densities of states (VDOSs), g(eff)(R)(omega) and g(N)(omega). Both the VDOSs show clear evidence of surface-induced vibrational modes, due to the local order distortion with respect to the bulk state.