Ultraviolet Brillouin scattering as a new tool to investigate disordered systems

The construction of an inelastic ultraviolet scattering (IUVS) beamline at the ELETTRA synchrotron facility allows studying the density fluctuation spectrum of disordered systems in the mesoscopic momentum and energy transfer region not accessible by other spectroscopic techniques. We will present recent results obtained on liquid water and xenon. In water we were able to measure the temperature dependence of the structural relaxation time showing that the divergence in the transport properties can be explained in the framework of the mode coupling theory. In xenon we were able to measure the dynamic structure factor in the hydrodynamic regime: this will open up the possibility to perform resonant Brillouin measurements by tuning the incident photon energy.