[omarshehab]

I am trying to simulate a circular chain (ring) of molecules which are planar (two dimensional).

Can anyone please give me an example of the molecular chain which can stay as planar with it's minimum energy state is planar. A published study on the evolution of the geometry of the molecule will be highly helpful.

[Arkcon]

The molecule benzene is very common and is well known to be a planar circular molecule. http://en.wikipedia.org/wiki/Benzene#Structure  I don't really understand what you mean by "A published study on the evolution of the geometry of the molecule will be highly helpful."  I'm assuming you think this sort of molecule is way more rare, and the science behind it way more contemporary, than the concept really is.