[CP2K-user] [CP2K:17537] Temperature in NVT AIMD rised to extermely high

[Jessie wang]

Thank you Lucas. 

I've applied  geo-opt before AIMD, temperature still rised a lot. But now I 
know the temperature rising is because the initial geometry from your 
advice. I'll try to improve initial geo. And it is also a good advice to 
add D3 dispersion correction.

I have another question, when we run AIMD, the outer sphere of water 
molecules sometimes run too far away from our system, and actually, the box 
is in a right size. What should I do to limit the motion of water to make 
it not run too far.


Best,

Jessie


On Wednesday, August 24, 2022 at 2:48:59 AM UTC+8 Lucas Lodeiro wrote:

> As a first glance, the problem is probably located on your initial 
> geometry... Packmol generates *good* solvation spheres, but they are far 
> away from the minimal energy geometry, and probably the forces on atoms at 
> the first step are very high. This explains why your kinetic energy rised a 
> lot, a huge amount of potential energy is changing to kinetic energy. When 
> I run this type of AIMD, usually relax the structure first with classic MD 
> with OPLS-AA forcefield, to get a better geometrical guess to start the 
> AIMD. Otherwise, you can do a geometrical relaxation (a non-tight 
> relaxation) in ORCA at the same level to get a better geometrical guess. 
> Also, I would add D3(BJ) dispersion correction to your calculation.
>
> Regards - Lucas
>
> El mar, 23 ago 2022 a las 13:57, Jessie wang (<wangch... at gmail.com>) 
> escribió:
>
>> Dear all,
>>
>> I'm trying to do NVT AIMD for a system (a cluster surrounded by water 
>> molecules). The water molecules was generated by packmol with tolerance 2.0.
>> I was set temperature to 298.15K, but after several steps, it rised to 
>> hundreds even thousands K.  I was used NOSE-HOOVER thermosat, and tried 
>> CVSR also. it does not work.
>>
>>  Here I attached my input file, and any help would really appreciated. 
>>
>> Thanks
>>
>>
>> Best,
>> Jessie
>>
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