title: Dynamics and critical damping of capillary waves in an ionic liquid.
abstract: The dynamics of thermal capillary waves (CWs) on an ionic liquid's surface are studied at the transition from propagating to overdamped CWs by x-ray photon correlation spectroscopy. The analysis considers both homodyne and heterodyne contributions, and yields excellent full line-shape experiment-theory agreement for the structure factor. The CWs' Brillouin scattering becomes extinct at a critical temperature Tc JK approximately 10 K above Tc LL , the propagating modes' hydrodynamic limit, in agreement with linear response theory. Surprisingly, the same power law applies at both Tc. The results rule out the presence of a suggested surface dipole layer.
authors.affiliation: Physics Department and Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Sloutskin
authors.forename: P
authors.initials: P
authors.lastname: Huber
authors.forename: M
authors.initials: M
authors.lastname: Wolff
authors.forename: B M
authors.initials: BM
authors.lastname: Ocko
authors.forename: A
authors.initials: A
authors.lastname: Madsen
authors.forename: M
authors.initials: M
authors.lastname: Sprung
authors.forename: V
authors.initials: V
authors.lastname: Schön
authors.forename: J
authors.initials: J
authors.lastname: Baumert
authors.forename: M
authors.initials: M
authors.lastname: Deutsch