A comparative study of thermal pressure coefficients of liquid alkali metals using equation of state and dense fluid theory

ABSTRACT

A simple analytical expression is derived to calculate the thermal pressure coefficients of liquid alkali metals. First, a modified linear isothermal regularity is applied to calculate the thermal pressure coefficients for caesium (Cs) and rubidium (Rb) in different thermodynamic states. The results obtained show that the calculated thermal pressure coefficients increase with increase in the density and decrease in the temperature. The extent of deviation between the calculated thermal pressure coefficients from the modified regularity and experimental values reduce remarkably with respect to those obtained from the primary isothermal regularity. Secondly, the thermal pressure coefficients are determined by the accurate dense fluid theory for a hard-sphere system. A comparative study of the predicted thermal pressure coefficients for both Cs and Rb shows that the results obtained by the isothermal regularity theory are closer to the experimental data with respect to the ones obtained from the statistical thermodynamic method.

GRAPHICAL ABSTRACT

KEYWORDS:

• Thermal pressure coefficients
• isothermal regularity
• liquid alkali metals
• hard-sphere fluid

Highlights

• A simple analytical expression is derived to calculate the thermal pressure coefficient.

• A modified linear isothermal regularity applied to the liquid alkali metals.

• Predictions for the thermal pressure coefficient of LAMs are investigated.

• The calculated results were compared with the available experimental data.

Acknowledgments

We acknowledge the financial support of Shahrood University of Technology for this work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Shahrood University of Technology.