Dear LAMMPS users,
I’m going to calculate the equilibrium tempearture of the system under NPH ensemble over 100000 steps. I’ve used the following commands. The problem is that the tempearture keeps decreasing to 300. I appreciate if you could help me.
fix npt all npt temp 590 590 0.1 x 0 0 0.1 drag 1
run 100000
unfix npt
fix nph all nph x 0 0 0.1 drag 1
run 100000
Regards
Dear LAMMPS users,
I'm going to calculate the equilibrium tempearture of the system under NPH
ensemble over 100000 steps. I've used the following commands. The problem is
that the tempearture keeps decreasing to 300. I appreciate if you could help
me.fix npt all npt temp 590 590 0.1 x 0 0 0.1 drag 1
run 100000
unfix npt
fix nph all nph x 0 0 0.1 drag 1
run 100000
impossible to say without knowing what else is going on in your system.
also, why do you need the drag flag? that'll kill whatever ensemble
you'd think you'd sample.
axel.
Dear Axel,
Many thanks for your reply. 590 K in npt ensemble is close to the melting point of the solid. My intention is to compute the equilibrium temperature over a long time under nph in order to diminish fluctuations and get a more accurate temp.
Regards
Dear Axel,
Many thanks for your reply. 590 K in npt ensemble is close to the melting point of the solid. My intention is to compute the equilibrium temperature over a long time under nph in order to diminish fluctuations and get a more accurate temp.
That doesn’t answer my question nor does it provide any additional information about your input, yet it raises more questions.
I assume you are aware, that simulations near phase transitions are particularly subject to finite size effects.
Axel