title: Observation of heterodyne mixing in surface x-ray photon correlation spectroscopy experiments.
abstract: We report measurements of propagating capillary waves on a liquid water surface at T=5 degrees C with x-ray photon correlation spectroscopy. The experiment has been performed under grazing incidence conditions with an incoming x-ray beam below the critical angle of total external reflection. In the q region investigated the measured intensity-intensity autocorrelation functions of the liquid water surface were found to be heterodyne signals, i.e., a combination of first- and second-order correlation functions g(1)(tau) and g(2)(tau).
authors.affiliation: Experimentelle Physik I, Universität Dortmund, Dortmund, Germany. gutt@physik.uni-dortmund.de
authors.forename: C
authors.initials: C
authors.lastname: Gutt
authors.forename: T
authors.initials: T
authors.lastname: Ghaderi
authors.forename: V
authors.initials: V
authors.lastname: Chamard
authors.forename: A
authors.initials: A
authors.lastname: Madsen
authors.forename: T
authors.initials: T
authors.lastname: Seydel
authors.forename: M
authors.initials: M
authors.lastname: Tolan
authors.forename: M
authors.initials: M
authors.lastname: Sprung
authors.forename: G
authors.initials: G
authors.lastname: Grübel
authors.forename: S K
authors.initials: SK
authors.lastname: Sinha