title: Multistage structural evolution in simple monatomic supercritical fluids: superstable tetrahedral local order.
abstract: The local order units of dense simple liquid are typically three-dimensional (close packed) clusters: hcp, fcc, and icosahedrons. We show that the fluid demonstrates the superstable tetrahedral local order up to temperatures several orders of magnitude higher than the melting temperature and down to critical density. While the solid-like local order (hcp, fcc) disappears in the fluid at much lower temperatures and far above critical density. We conclude that the supercritical fluid shows the temperature (density)-driven two-stage "melting" of the three-dimensional local order. We also find that the structure relaxation times in the supercritical fluid are much larger than ones estimated for weakly interactive gas even far above the melting line.
authors: Institute of Metallurgy, Ural Division of Russian Academy of Sciences, 620016 Yekaterinburg, Russia.
authors: R E
authors: RE
authors: Ryltsev
authors: Moscow Institute of Physics and Technology, 141700 Moscow, Russia and L. D. Landau Institute for Theoretical Physics, Russian Academy of Sciences, 142432, Moscow Region, Chernogolovka, Russia and Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330, USA and Institute for High Pressure Physics RAS, 142190, Moscow, Russia.
authors: N M
authors: NM
authors: Chtchelkatchev