Regularities of liquid potassium at different temperatures

Huaming Li,Yanting Tian,Yong Li Sun,Hao Ding,Mo Li

doi:10.1063/1.5100834

Abstract

Several new regularities in liquid potassium have been found from the existing experimental data and calculated thermodynamic properties along the isothermal lines with the equation of state (EoS) of a power law form. The quantity (Z − 1)V2 is linearly proportional to V2 with a common intersection point for all isotherms at high temperature and PintV versus V−2 is nearly linear, where Z, V and Pint are compressibility factor, molar volume and internal pressure. Both the isothermal bulk modulus and internal pressure are nearly a linear function of pressure at constant temperature. There is a linear relationship existing between the calculated reduced isothermal bulk modulus and V−2. Based on the linear isotherm regularity EoS, analytical expression of thermodynamic properties of liquid potassium can be obtained. Furthermore, we found crossing points existing in the isobaric thermal expansion coefficient and Anderson-Grüneisen parameter.

Highlights

In despite of the existence of complexities of thermodynamics and structure in dense liquids, some simple regularities were derived from experimental data.1–3 Parsafar and Mason1 reported a linear isotherm regularity equation of state (EoS) that (Z − 1)V2 is linear in V−2 for thirteen fluids where Z =PV RT is the compressibility factor, V is the molar volume, P is the pressure, R is the gas constant and T is the temperature
With an EoS of the power law form, we studied the thermodynamic properties of liquid potassium under high temperature and high pressure
The calculated isothermal bulk modulus, the specific volume, and internal energy for liquid potassium with the variation of pressure are in good agreement with the available data from experiments

Summary

Introduction

In despite of the existence of complexities of thermodynamics and structure in dense liquids, some simple regularities were derived from experimental data. Parsafar and Mason reported a linear isotherm regularity EoS that (Z − 1)V2 is linear in V−2 for thirteen fluids where Z =PV RT is the compressibility factor, V is the molar volume, P is the pressure, R is the gas constant and T is the temperature. BT V RT with the isothermal bulk modulus BT) as a function of density by Huang and O’Connell.. BT V RT with the isothermal bulk modulus BT) as a function of density by Huang and O’Connell.2 Goharshadi and his coworkers found that there is the existing near-linear behavior of (2Z − 1)V3. Based on the linear isotherm regularity EoS, the average potential energy between atoms is approximated by the generalized Lennard-Jones (n, m) potential with taking into account the contribution from the nearest neighbors only. These empirical regularities are valid for the related pure liquids and liquid mixtures under a considerable range of temperature and pressure

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Conclusion