title: Structural relaxation in liquid water by inelastic UV scattering.
abstract: Using the novel synchrotron radiation based inelastic ultraviolet scattering technique, the dynamic structure factor of normal and supercooled liquid water has been measured at a momentum transfer Q approximately equal to 0.1 nm(-1), in the temperature range 260-340 K. The structural (alpha) relaxation has been observed in the supercooled temperature region (T< or =273 K), where the inverse relaxation time matches the frequency of the probed sound modes. The T dependence of the relaxation time shows a diverging behavior with a critical temperature T approximately equal to 220 K. These results provide a unique experimental opportunity to frame the dynamics of water in the mode-coupling theory.
authors.affiliation: Sincrotrone Trieste, S.S. 14 km 163, 5 in Area Science Park, 34012 Basovizza Trieste, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Masciovecchio
authors.forename: S C
authors.initials: SC
authors.lastname: Santucci
authors.forename: A
authors.initials: A
authors.lastname: Gessini
authors.forename: S
authors.initials: S
authors.lastname: Di Fonzo
authors.forename: G
authors.initials: G
authors.lastname: Ruocco
authors.forename: F
authors.initials: F
authors.lastname: Sette