[gmx-users] Radial distance restraints

[Bob Johnson]

Hello everyone,
Is there any way to use radial distance restraints? For example, my system is
cylindrically symmetric (it's a carbon nanotube) and I would like to restrain
molecules to a certain distance away from the nanotube axis. Obviously, I don't
care if they the slide along the z-axis or change their orientation with respect
to the nanotube surface. That is why only radial constraints (sqrt(x^2 + y^2) =
constant) will work. Any way to do this?
Thanks,
Bob Johnson