A correlation of maximum attainable superheat and acentric factor of alkali metals

• Maximum attainable superheat and acentric factor of Cs, Rb and K are correlated.
• Cs, Rb and K obey single-parameter law of corresponding states.
• Maximum attainable superheat is a thermodynamic similarity parameter of Cs, Rb and K.
• Acentric factor is a thermodynamic similarity parameter of Cs, Rb and K.

The maximum attainable reduced temperature of superheating at zero pressure and the acentric factor of cesium, rubidium and potassium are correlated through the generalized van der Waals equation of state. This three-parameter equation differs from the known van der Waals equation of state by the modified expression for molecular pressure. The obtained correlation fits the experimental data for the maximum attainable reduced temperature of superheating at zero pressure, with an accuracy of 2.756%, 2.408% and 2.638%, for cesium, rubidium and potassium, respectively. It has also been established that cesium, rubidium and potassium obey the single-parameter law of corresponding states with the maximum attainable reduced temperature of superheating at zero pressure or the acentric factor as the thermodynamic similarity parameter.