Coomber's relationship

Coomber's relationship can be used to describe how the internal pressure and dielectric constant of a non-polar liquid are related.

As $$p_i=\left(\frac{\partial E}{\partial V}\right)_T\,$$, which defines the internal pressure of a liquid, it can be found that: $$p_i = n \cdot I \cdot b(T) \frac{N^2\alpha^2}{V^{n+1}}$$ where where for most non-polar liquids $$n=1$$
 * $$N$$ is equal to the number of molecules
 * $$I$$ is the ionization potential of the liquid
 * $$b(T)$$ is a temperature dependent relation based on numerical constants of the pair summation from inter-particle geometry
 * $$\alpha$$ is the polarizability
 * $$V$$ is the volume of the liquid