[DFTB-Plus-User] Rotational motion and Metadynamics

[Simon Ghysbrecht]

Dear DFTBers,

I am trying to use DFTB+ in combination with PLUMED to do metadynamics and US on a molecule in vacuum. I’m using velocity Verlet molecular dynamics with a Nose-Hoover chain thermostat. When visualising the trajectories, however, I noticed the molecule is spinning, i.e. generates a lot of rotational motion. I know some MD software removes angular motion to avoid this.

I am slightly worried that this rotation is coupled to the biasing of my CV, which can lead to nonconverging or  inaccurate free energy profiles.

- Does anyone know if rotational motion can be removed from the molecular dynamics simulation using DFTB+?
- Alternatively, does anyone know if I can use another software combination which might avoid this angular motion? (For example, I read articles with people using dftb in GROMACS, but found little documentation on this)
- Or any other insight from people with experience in these kind of free energy calculations are very welcome :)

BR,
Simon