Stefan's formula

In thermodynamics, Stefan's formula says that the specific surface energy at a given interface is determined by the respective enthalpy difference $$ \Delta H^*$$. $$\sigma = \gamma_0 \left( \frac{\Delta H^*}{N_\text{A}^{1/3}V_\text{m}^{2/3}}\right),$$ where σ is the specific surface energy, NA is the Avogadro constant, $$\gamma_0$$ is a steric dimensionless coefficient, and Vm is the molar volume.