Reanalysis of Microgravity Heat Capacity Measurements Near the SF₆ Liquid–Gas Critical Point

Abstract

The earlier microgravity heat capacity measurements in SF₆ by Haupt and Straub have been reanalyzed in this study. A simple power law as well as the minimal-subtraction renormalization (MSR) scheme were used to fit the measurements. In this paper the unexpected result that the SF₆ heat capacity measurements appear to be within the asymptotic critical region all the way out to a reduced temperature |t| ≃ 10⁻² is presented. This conclusion is in contradiction with the smaller asymptotic region |t| < 1.6× 10⁻⁴ found in the original investigation. These heat capacity measurements were found to be inconsistent with renormalization group predictions using SF₆ compressibility measurements.