Lennard-Jones potential

Atoms of a noble gas reach an equilibrium distance from each other when an attracting van der Waals force balances a repelling force the result of overlapping electron orbits. The strength at which these two forces balance is the so-called Lennard-Jones potential (L-J potential).

Subject to assumptions about the physical properties of the molecules, the L-J potential may be used to calculate an approximation for their separation. Other more recent methods, such as the Stockmayer equation and the so-called multi equation, describe the interaction of molecules more accurately.

The L-J potential is of the form where ε is the well depth and σ is the hard sphere radius.