Ross melting rule

The Ross melting rule states (Eq. 4 ):

$A={\frac {1}{2}}NE(0)-Nk_{B}T\ln \upsilon -Nk_{B}T\ln \upsilon _{f}^{*}$

where $A$ is the Helmholtz energy function, $N$ is the number of cells, $E(0)$ is the potential at the centre of the cell, $k_{B}$ is the Boltzmann constant, $T$ is the temperature, $\upsilon$ is the volume of the cell, and $\upsilon _{f}^{*}$ is the dimensionless reduced volume in configuration space.