You have now succeeded in creating a custom topology for a linear molecule using virtual sites and used a simple simulation to confirm that the moment of inertia was reproduced correctly. This tutorial can serve as a basis for creating topologies for other linear molecules or functional groups.

If you have suggestions for improving this tutorial, if you notice a mistake, or if anything is otherwise unclear, please feel free to email me. Please note: this is not an invitation to email me for GROMACS problems. I do not advertise myself as a private tutor or personal help service. That's what the GROMACS User Forum is for. I may help you there, but only in the context of providing service to the community as a whole, not just the end user.

Happy simulating!