Structural changes in supercritical fluids at high pressures
Year: 2008
Authors: Santoro M., Gorelli F.A.
Autors Affiliation: European Lab Non Linear Spect LENS, I-50019 Florence, Italy; Univ Roma La Sapienza, CNR INFM CRS SOFT, I-00185 Rome, Italy.
Abstract: The structure of an archetypal model simple fluid system as argon has been investigated by x-ray diffraction at high pressures and room and high temperatures. Despite the markedly supercritical conditions (T=2-4T(c), P > 10(2)P(c)), the structure factor S(Q) is very similar, close to the melting line, to that observed in the liquid phase, thereby assessing a liquidlike structure with high atomic correlation, as proposed in a recent inelastic experiment. On the other hand, the S(Q) continuously changes upon approaching the extrapolation of the liquid-gas coexistence line in the (P/P(c), T/T(c)) plane, ultimately exhibiting low atomic correlation, which reasonably indicates intermediate character between liquid and gas. The analysis of the S(Q)s based on the hard-sphere model shows that the changes are driven by the decrease in the packing fraction and the increase in the nearest-neighbor distance with decreasing pressure.
Journal/Review: PHYSICAL REVIEW B
Volume: 77 (21) Pages from: 212103-1 to: 212103-4
KeyWords: Argon; Equation; StateDOI: 10.1103/PhysRevB.77.212103ImpactFactor: 3.322Citations: 30data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-11-10References taken from IsiWeb of Knowledge: (subscribers only)
