Parabola vs flat trend? (for total energy VS distance)

[perfetti]

Dear Everyone,
       I modified the central part of a device, and am trying to get the equilibrium distance between the electrode and the central part.
       I change the value of the distance, and get the corresponding total energy. However, I got a curve with a flat trend, instead of a parabola one.
       I feel a little bit strange, cause for the original device, I got a parabola curve. Is there possible that the total energy vs distance should become flat?  Or is that because I modified the central part, then something got changed? I cannot explain this in theory.
       The calculated curves are attatched. Thanks everyone for your advice.
      

[kstokbro]

I do not understand exactly what you are doing. Which distance are you changing?
Can you attach the script you use, this might help.

[perfetti]

I am changing the gap between the electrode and the central region.
They are not zero as you view it.
I am plotting the total energy of the whole system vs this gap.

I do not understand exactly what you are doing. Which distance are you changing?
Can you attach the script you use, this might help.

[Nordland]

Which version of ATK are you using?

I guess it is one of the older, and you systems converged to zero charge every time.

[howard77]

THIS IS AN AMAZING FORUM.. I have never seen people helping oyt each other so well in other sites so well and so patience. it feels like i m in some kind of class room.. Thanks a tonn.. keep the good work goin on..
i also got great knowledge after reading this post.