Employing physical concepts to interpret thermodynamic phenomena was common in the past. For example, van der Waals introduced molecular interactions into the state equation of the ideal gas to correct the deviation of real gas . Sutherland developed the hard-sphere model (the so-called Sutherland potential) by adding an attractive r -3 potential, identical to the van der Waals cohesive force, to improve the kinetic gas theory for atomic and molecular collisions . Drude model of oscillating dipoles between two atoms provides a straightforward way to introduce the dispersion force , . London gave the famous attractive long-range r -6 behavior for the dispersion force , . These are the natural responses to Newton's law of universal gravitation that molecular interaction is attractive. However, a repulsive force is needed to study the gas-liquid properties. Mie separated the two-body interaction potential into short-range repulsive and long-range attractive terms . Based on Grüneisen potential within the solid-state and materials physics community , Lennard-Jones further developed it and gave a famous equation of potential: - U (𝑟) = 4𝜀 [ -] (1)