I am trying to figure out the best way to implement a core-shell model where the core of an atom interacts with its shell via a spring-like bond but the rest of the particles have a Coulumbic interaction. I will use oxygen as my example.
The problem is that if I apply a Coulumbic interaction to everything, the cores and the shells will become unstable due to the 1/r near r=0. If I turn off Coulumbic interactions between all the oxygen shells and all the oxygen cores, I will get an unrealistic result. Example: the core of oxygen A and does interact with the shell of oxygen B but does not interact with the shell of oxygen A via Coulumbic force.
How should I approach this?
PS. My Rydberg potential works, I should have a description written by the end of the week.