Abstract
Molecular dynamics (MD) results for the dynamic structure of a gas mixture at two densities (15.8 and ) show a clear crossover from hydrodynamic modes to distinct excitations for the two species. The higher density dispension curve neatly shows high- and low-frequency branches setting on with a rather localized transition. The lower density results agree very well with existing neutron scattering data and, in particular, display hydrodynamic behavior up to , in contrast with the conclusions of previous simulation studies. A smooth transition to fast sound is shown to take place for , where the present MD data fill the existing gap in the experimental results.
- Received 7 June 2001
DOI:https://doi.org/10.1103/PhysRevLett.88.085502
©2002 American Physical Society