The most stable bond length is around 8 Å, where the interaction energy is flattest.

The bond length of this molecule is ~3.2 Å as the interaction energy is highest at this distance.

Nucleus-nucleus repulsion causes the molecule to dissociate at long distance.

The most stable bond length is close to 3.8 Å, as the interaction energy is most negative at this distance.

The average distance between the electrons and the nucleus of an argon atom is ~3.8-3.9 Å.