[CP2K-user] [CP2K:17577] Temperature in NVT AIMD rised to extermely high

[Niharendu Choudhury]

 Hi Jessie, 
I think the best option is to run a short simulation using classical MD and 
then start ab-initio simulation from the final configuration obtained from 
the classical MD.
Regards
Niharendu

On Thursday, August 25, 2022 at 3:42:41 AM UTC+5:30 Lucas Lodeiro wrote:

> Hi Jessie,
>
> If your optimized geometry still get high temperature at the beginning of 
> AIMD, maybe it reached a flat profile of the PES or a metastable structure 
> with high energy. In this case I would run an AIMD with NH thermostat in 
> the MASSIVE setting with a short timescale, to couple thightly each DoF 
> with the thermostat, maybe this helps to thermalize the system, obviously 
> after that you will need to equilibrate with a global thermostat and 
> reasonable timescale.
> It is reasonable that some solvent molecules fly out of the system when 
> the temperature rises a lot.... With an equilibrated system this would not 
> happen. By the way, there are restraints in CP2K to add confinement 
> potentials.
>
> Regards - Lucas
>
> El mar, 23 ago 2022 a las 23:14, Jessie wang (<wangch... at gmail.com>) 
> escribió:
>
>> 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
>>>>
>>>> -- 
>>>> You received this message because you are subscribed to the Google 
>>>> Groups "cp2k" group.
>>>> To unsubscribe from this group and stop receiving emails from it, send 
>>>> an email to cp2k+uns... at googlegroups.com.
>>>> To view this discussion on the web visit 
>>>> https://groups.google.com/d/msgid/cp2k/7856dc7f-d236-477b-8c20-98fdd1d3037bn%40googlegroups.com 
>>>> <https://groups.google.com/d/msgid/cp2k/7856dc7f-d236-477b-8c20-98fdd1d3037bn%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>> .
>>>>
>>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "cp2k" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to cp2k+uns... at googlegroups.com.
>>
> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/cp2k/5dd3975a-13ef-451e-9b73-ff023bb05605n%40googlegroups.com 
>> <https://groups.google.com/d/msgid/cp2k/5dd3975a-13ef-451e-9b73-ff023bb05605n%40googlegroups.com?utm_medium=email&utm_source=footer>
>> .
>>
>

-- 
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+unsubscribe at googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/f7c3f73a-a323-42e1-8c38-eac4524be71dn%40googlegroups.com.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20220829/ab94db97/attachment-0001.htm>