Correlation of isothermal compressibility coefficient and reduced bulk modulus of dense fluids using perturbed linear Yukawa isotherm regularity

A new simple analytical expression has been derived for predicting the reduced bulk modulus (Br = d1= RT_d@ p=@._T) and isothermal compressibility coefficient (.T = 1=.RTBr) of dense fluids using a new proposed equation of state (EoS) known as the linear Yukawa isotherm regularity (LYIR). The advantage of the derived expressions is that the variation of Br and.T with the changes of the parameters of Yukawa effective pair potentials (eeff, seff and.eff) can be investigated. The calculated isotherms of Br and.T obtained from the derived expression show a good agreement with the literature data for some selected dense fluids. The variation of Br with seff of effective pair Yukawa potential was studied and it was observed that the increase in the value of seff accompanied by the increase of Br. The ability of the derived expressions for predicting Br and.T was compared with the corresponding expressions obtained from the linear isotherm regularity (LIR) and Goharshadi-Morsali-Abbaspour (GMA) EoSs, which are based on an average effective near neighbour pair interaction. It was found that the ability of LYIR EoS in predicting Br is comparable with LIR and GMA EoSs. This comparison also showed that the LYIR EoS can be successfully used to predict and correlate the Br and.T of dense fluids and the hard-core Yukawa potential can be adequately used in the modelling of the thermodynamical and thermo-physical properties of the dense systems. Finally, the derived expression for Br predicted the common bulk modulus region at which the different isotherms of Br vs. density intersect each other in a density region.