Problem with brownian dynamics in lammps

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1

Dear Dr. Kohlmeyer,
Thanks for answering to my request.
In attachment I’m sending the lammps code (named norot_noprop_noise.lmp) I am using and the restart file that represent the initial configuration from which my simulation starts (named restart_short.400).
In this version of the code the Tstart=Tstop value is set to 10^-3 in lj units (but I’ve tried also with lower values, until 10^-15).
The temperature is written in the output file.
It can be observed that the system is flowing both directly looking at the video made with the damp files and indirectly via the mean square displacement (that I’m calculating outside lammps, using the trajectories).

Best regards,
Linda Ravazzano

norot_noprop_noise.lmp (2.5 KB)

restart_short.400 (274 KB)

2

Dear all,
following my last email, I’ve done some further analysis to see where the problem can come from.
I suspect that the problem can arise from the combined use of the lammps commands “fix langevin … omega yes” and “fix nve/sphere disc”.
Is it possible that the rotational degrees of freedom of my 2D discs are not taken into account properly during the integration?
Could it be the reason why the temperature of my system does not correspond to the temperature I set via the fix langevin command?

Thanks in advance.
Best,
Linda