Mainz 2022 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 48: Instrumentation XII

HK 48.2: Talk

Wednesday, March 30, 2022, 16:15–16:30, HK-H4

Crossing the Widom line: Cluster formation as sensitive probe of supercritical fluids — •Sophia Vestrick, Clara Fischer, and Alfons Khoukaz — Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany

In contrast to the well-defined vapor pressure curve for fluids below the critical point, there is no distinct characterization as liquid or gas in the supercritical regime. Hence, the Widom line is proposed as location of a phase transition higher order. Whereas its experimental determination is typically challenging, we found a new and simple method for precisely measuring the phase transition of supercritical hydrogen using the formation of cluster beams. Due to the two distinct cluster formation mechanisms in the liquid and in the gaseous phase, an unambiguous assignment of supercritical fluids to liquid-like and gas-like regions is possible. The novel determination of the Widom line using cluster beams represents a universal method that can be easily applied to a wide range of elements or chemical compounds. This project has received funding from BMBF (05P21PMFP1), GSI FuE (MSKHOU2023) and the EU's Horizon 2020 programme (824093).