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Re: [lammps-users] temp doesnt increase during equilibration
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Re: [lammps-users] temp doesnt increase during equilibration

From: Wes Barnett <w.barnett@...668...>
Date: Thu, 24 Aug 2017 13:10:48 -0400

> On Thu, Aug 24, 2017 at 5:53 AM, Meral Sharkas via lammps-users <> wrote:
>> I am trying to equilibrate my system at 300 k and 0 bar, my system is starting at high pressure so I relaxed my box at 0 k and used nve/lim to control the pressure. When I tried to raise the temperature to 300 k I found that the max temp reached was 30 k. May I ask what would be the reason for that?
>> timestep 0.001
>> fix  2 all npt temp 1 300.0 100 iso 0.0 0.0 1000

On Thu, Aug 24, 2017 at 11:36 AM, Stefan Paquay <stefanpaquay@...24...> wrote:
> I'm thinking that it is a problem with your temperature time constant. Nosé-Hoover thermostats can take a long time to equilibrate. Try reducing the time constant to something smaller.

I would add that the manual recommends setting Tdamp to around 100 *timesteps* and is written in *time units*. So instead of 100 for Tdamp, 0.1 would be more realistic given the time step of 0.001. Pdamp can be adjusted likewise.

James "Wes" Barnett
Postdoctoral Research Scientist
Department of Chemical Engineering
Kumar Research Group
Columbia University