Structural Transition in Supercritical Fluids

Abstract

The extension of the saturation curve 𝑃𝑠(𝑇) on the PT diagram in the supercritical region for a number of monocomponent supercritical fluids by peak values for different thermophysical properties, such as heat capacities 𝐶𝑝 and 𝐶𝑣 and compressibility has been studied. These peaks signal about some sort of fluid structural transition in the supercritical region. Different methods give similar but progressively diverging curves 𝑃st(𝑇) for this transition. The zone of temperatures and pressures near these curves can be named as the zone of the fluid structural transition. The outstanding properties of supercritical fluids in this zone help to understand the physical sense of the fluid structural transition.