Langevin dynamics

Dear LAMMPS users and developers,

I have a question regarding Langevin dynamics in LAMMPS. I would like to do a simulation under the NVT ensemble with Langevin thermostatting and a modified Velocity Verlet for time integration as in N. Gronbech-Jensen and O. Farago, Mol. Phys. 111, 983 (2013). I am applying an external force on some atoms, and hence the NVE ensemble would not be valid. Would the following four lines produce a NVT ensemble with Langevin dynamics?

fix langevinFix all langevin \{temp1\} {temp2} \{relaxationtime\} {seed} gjf yes
fix lforce left aveforce NULL NULL -\{force\} fix rforce right aveforce NULL NULL {force}
fix nveFix all nve

On the LAMMPS page the combination of fix langevin and fix nve is mentioned as a method to achieve Brownian dynamics, which is not what we intend as we are applying an external force to the system. How could one achieve Langevin dynamics simulations in LAMMPS?

Thank you in advance!

Best regards,

It would not technically be an NVT ensemble if you’re applying an external force. It will produce Langevin dynamic though.

Thank you! Yes, I was imprecise, I meant of course simulations at approximately constant temperature.

Best regards,

  1. mar. 2018 kl. 19:49 skrev Stefan Paquay <[email protected]…24…>: