Lennard-Jones potential

There are limits to these properties, and everything's related to the bonding — the Lennard-Jones potential, the energy potential for bonding. So if this is the zero of energy, this is positive energy and negative energy of bonding. Take an atom right here, another atom out here at some distance — the potential energy of bonding looks like this. The equilibrium distance of separation is here. Out at infinity there's very little attraction. There's only attraction within three or four atomic distances. Ten atomic distances away and those atoms can hardly see each other.