Yang–Yang critical anomaly strength parameter from the direct two-phase isochoric heat capacity measurements near the critical point

New technique of the Yang–Yang critical anomaly strength function, Rμ(T  ), determination from direct two-phase liquid (CV2′) and vapor (CV2″) isochoric heat capacity and liquid (V′) and vapor (V″) specific volumes measurements at the saturation have been developed. Our measured two-phase (liquid and vapor) isochoric heat capacities (CV2″,CV2′) and liquid and vapor specific volumes (V″,V′) data at saturation near the critical point have been used to accurately determine the Yang–Yang anomaly strength parameter, Rμ(T = Tc) = Rμ0, for various molecular liquids. The derived values of the Yang–Yang critical anomaly strength function show trend to negative infinity near the critical point as predicted by the theory (Cerdeiriña et al., 2015) based on compressible cell gas (CCG) model that obey complete scaling with pressure mixing. The physical nature and details of the temperature and the specific volume dependences of the CV2 and correct estimations of the contributions of various terms (chemical potential CVμ and vapor-pressure CVP) to the measured total two-phase heat capacity were discussed in terms of the Yang–Yang anomaly parameter.