I wanted to show students how "bonding" releases energy but couldn't find any simulations online so I wrote one based on
Bruce Sherwood's programs (which I have found to be a great resource, by the way). Not sure if this is useful to anyone else but my students found it very useful and I figured I'd pass it on in case (a) anyone else wants to use them or (b) it doesn't really show what I want it to show and someone (in which case I am sure someone will correct me).
One simulation shows two particles under an attractive force, allowing for elastic collisions. They just continue to bounce off each other.
The other simulation shows the same two particles but in a field of neutral particles. The two particles eventually "stick together" after transferring their energy to the surrounding particles.