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), which describes the separation of the atoms. The L-J potential does make a lot of assumptions about the physical properties of the molecules it attempts to describe and is therefore quite inaccurate.

There are other equations which describe the interaction of molecules with more accuraccy.Such as the stock mayer equation and the so called multi equation.