Experimental and modelling evidence for structural crossover in supercritical CO${}_2$

Abstract

Physics of supercritical state is understood to a much lesser degree compared to subcritical liquids. Carbon dioxide in particular has been intensely studied, yet little is known about the supercritical part of its phase diagram. Here, we combine neutron scattering experiments and molecular dynamics simulations and demonstrate the structural crossover at the Frenkel line. The crossover is seen at pressures as high as 14 times the critical pressure and is evidenced by changes of the main features of the structure factor and pair distribution functions.

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• Transition in the supercritical state of matter: experimental evidence
• Universal interrelation between dynamics and thermodynamics of fluids: dynamically-driven "c"-transition
• Similarity between the kinematic viscosity of quark-gluon plasma and liquids at the viscosity minimum
• Pronounced structural crossover in supercritical water
• Crossover of dynamical instability and chaos in the supercritical state