[CP2K:10607] Re: Equilibration in NVT MD run

raghav saxena raghavs... at gmail.com
Mon Aug 6 09:39:43 CEST 2018


Hey Martin,

                I removed the TEMP_TOL=100 line and changed the time
constant to 20 and I got this but the mean temperature is still not 310
even after 3.4 ps. Any suggestions?

Regards
Raghav

On Sun, Aug 5, 2018 at 2:30 AM, M. Brehm <brehmin... at gmail.com> wrote:

> Dear Raghav,
>
> I could imagine that this effect is due to the "TEMP_TOL   100" line.
> Please try to comment out this line.
>
> Apart from that, a thermostat time constant of 100 fs is relatively weak
> for an early equilibration. If there is much change in the structure of the
> system, the coupling of the thermostat might simply be too weak. I
> recommend to use a lower value (e.g. "TIMECON 20") in the early
> equilibration stages. The value of 100 fs is fine for production runs or
> late equilibration.
>
> One more comment: Your time step of 1.0 fs is fairly large for a system
> which contains hydrogen atoms. This is always a matter of taste, but I
> would go for 0.5 fs if hydrogens are involved. Otherwise, the integration
> error might become significant, leading to a drifting conserved quantity.
>
> Best regards,
> Martin
>
>
> Am Samstag, 4. August 2018 20:13:51 UTC+2 schrieb Raghav:
>>
>> Dear cp2k users,
>>
>>                         I am trying to equilibrate my system. I am doing
>> NVT simulation but the mean temperature of my system is not reaching the
>> target Temperature (310K) as can be seen in the figure attached. I am using
>> Nose Hoover Thermostat, Is there some problem with the parameters of the
>> thermostat or something else is the problem.
>>
>> Input file is attached.
>>
>> Regards
>> Raghav
>>
>
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