Obtaining the position

Dear Blender community,

I am a new Blender user. I have decided to use this software because it has a huge potential in designing complicated objects for later Molecular Dynamics (MD) simulations.

For this purpose, I have designed a simple nanocrystal like the one in the attached figure. Could someone explain to me please how I can extract through Python the position of the center of mass for each of the spheres that compose the nanocrystal to do MD simulations?

Thank you very much in advance for your time and help.

Regards Jose