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Re: [lammps-users] How to raise the temperature after box relaxation at 0K?

# Re: [lammps-users] How to raise the temperature after box relaxation at 0K?

 From: Stefan Paquay Date: Tue, 22 Aug 2017 18:09:19 -0400

That is impossible to say without the complete input deck. Perhaps there are atoms that are not moving, so the actual number of degrees of freedom is smaller than what LAMMPS assumes?

On Tue, Aug 22, 2017 at 5:49 PM, Meral Sharkas via lammps-users wrote:
Dear all,

Apologies but the temperature doesn't exceed 30 K and I tried several Tdamp and Pdamp. May I ask what could be the reason of that ?

Thank you

On Tuesday, August 22, 2017 11:10 PM, Meral Sharkas <eng_meral.sh10@...16...> wrote:

Dear Michal,

It worked .. Thank you very much I really appreciate it...

Regards

On Wed, Aug 23, 2017 at 12:04 AM, Michał Kański
Try starting from 1K instead of 0K.

Michal

From: Meral Sharkas via lammps-users
Sent: ‎2017-‎08-‎22 22:59
To: lammps-users@...396...sourceforge.net
Subject: [lammps-users] How to raise the temperature after box relaxation at 0K?

Dear Team,

I wander if you can help me with my question.

I am trying to relax my box at 0K to decrease pressure as much as I can as a start then I want to run my equilibration at 300 K and constant NPT ensemble.

When I ran the "fix/Npt" , I got Nans.

I suppose that the problem was "raising the temperature", so if that is the case, how can I raise the temperature to 300 K for equilibration?

timestep 0.0001
thermo 100
velocity      all create 0 7928459 dist gaussian
fix 1 all box/relax iso 0.0

#minimization

min_style cg
minimize 1e-25 1e-25 5000 100000
run 1000

#Equilibration
fix                     1 all npt temp 0 300.0 100 iso 0.0 0.0 1000
run 100000