Rigid Body Energy Minimization


I work with molecular crystal materials and I’m interested in doing rigid body/molecule energy minimizations using ASE in the same manner as rigid body optimizations in DMACRYS or GULP. Does anyone know if this has been implemented somewhere or if it is reasonably possible to implement?

Conceptually this would involve calculating net force and net torque on each molecule, thereby keeping the intramolecular bonds, angles etc constant. Simple constraints on bonds, angles etc aren’t applicable because the energy model is purely intermolecular and thus changing the bonds any distance for example produces unphysical results.

Many thanks for any advice