Abstract
A propagating excitation with a velocity of sound of is measured in at 294 between 4 and 14 , using inelastic x-ray scattering with 5 energy resolution. The existence of fast sound is therefore demonstrated in an energy-momentum region much wider than that of previous neutron measurements on . The equivalence of the fast sound velocity in and in rules out models where this mode propagates only on the hydrogen network. These results show the ability of inelastic x-ray scattering to study the collective dynamics of liquids.
- Received 12 April 1995
DOI:https://doi.org/10.1103/PhysRevLett.75.850
©1995 American Physical Society