Apply fix addforce to molecule center of mass

Is it possible to use the fix addforce to apply a spatially-varying
external force to the molecular center of mass (instead of each atom
individually)? The magnitude of the force would depend on the
position of the center of mass of the molecule.

Thanks!

Hi Stan. Probably is not possible with fix addforce as it is currently written, but it wouldn't be too hard to modify it to do what you want.

Paul