A Lennard-Jones for bound/unbound atoms?

[kirill77]

TL;DR Summary

The force between two atoms should depend on whether one of them is bound to a third atom or not, right? How is that taken into account when using Lennard-Jones?

I can't find anywhere information on how people treat bound/unbound condition for atoms with Lennard-Jones simulation. Say if I have 3 oxygen atoms flying around and two of them at some point become an O2 molecule, this means their electron shells are now fully occupied - so I am guessing the attractive force between any of those 2 bound atoms and the third (unbound) atom should decrease. At the same time repulsive component shouldn't be affected that much. Is there a way to simulate this with Lennard-Jones somehow? Should I have bound/unbound state associated with every oxygen atom so that I can take this into account when applying Lennard-Jones formula?

 

[Neville]

I recommend you to read: Chapter 4.2 in David Pettifor's Book: Bonding and Structure of Molecules and Solids. He discusses a generalized LJ Model and shows how the resulting structure depends on the relationship of repulsive and binding contributions.