criticism/ridicule if I've got it wrong:

If the two atoms are pushed together, then there is a repulsive force between

them of a positive magnitude. If they are separated by a distance r, then the

two forces (repulsive/attractive) are equal but opposite and the atoms are in a

state of equilibrium. At a separation greater than r, the force is that of

attraction, and if the separation is greater than 2r, then the attraction

tends to zero.

Potential Energy/Separation:

If the two atoms are separated by an infinite distance, then there is no

attraction between them, and there is no Potential Energy. But as they come

closer together, potential energyhttp://www.physicsforums.com/library.php?do=view_item&itemid=269 decrease until at a distance of r, potential

energy is at a minimum. If the separation is reduced further, the line of

Potential Energy passes through zero.

Why is the potential energy zero? What actually happens to the 2 atoms when the potential energy becomes zero?

I'm confused, can anyone clear this up for me please?

Thanks.