[CP2K-user] [CP2K:12357] Re: atomes go far away from box in NVT simulation

[mh H]

Thank you, dear Dr. Matt W, How about a system including a water droplet in
a big box? we must consider COMVEL_TOL? because in this condition(NVT,
BOMD) we have deformation and therefore moving the center of mass.

BEST

On Tue, Oct 15, 2019 at 2:59 AM Matt W <mattwa... at gmail.com> wrote:

> No. But if there are no external fields then the centre of mass motion
> should be zero.
>
> If it is not (and it won't be) there are some numerical errors. You need
> to decide what level of inaccuracy is OK for your simulation.
>
> On Monday, October 14, 2019 at 4:40:13 AM UTC+1, mh H wrote:
>>
>> without considering  COMVEL_TOL in MD section, calculation is wrong?
>>
>> On Tuesday, February 9, 2016 at 6:06:40 PM UTC+8, Matt W wrote:
>>>
>>> Hi Tao,
>>>
>>> The keyword COMVEL_TOL in MD section will allow you to remove center of
>>> mass motion.
>>>
>>> However, if it is drifting very far it probably indicates that your
>>> setup is not quite good enough in conserving energy/momentum etc.
>>>
>>> If particles are just diffusing out of the central periodic image, this
>>> is not a problem, as you note above. You, or VMD or whatever visualizer you
>>> use, can just wrap them back.
>>>
>>> Remember, in CP2K a nice thing is you can run a quick classical
>>> calculation to check how it handles COM motion etc with a nicely conserving
>>> setup, rather than waiting for a DFT run to finish.
>>>
>>> Matt
>>>
>>> On Tuesday, February 9, 2016 at 9:38:42 AM UTC, tao liu wrote:
>>>>
>>>> Hi All,
>>>>
>>>> I have tested the keyword &CENTER_COORDINATES, but this keyword just
>>>> works for the first step, CP2k will center all the atoms to the default
>>>> position cell/2.. But in the following steps, the center of atoms will
>>>> change along with simulation time. Do I understand correctly?  If yes, is
>>>> there anyway to carry out this &CENTER_COORDINATES keyword in every
>>>> timestep? Thanks.
>>>>
>>>> Tao
>>>>
>>> --
> 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 cp... at googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/cp2k/530c0a66-9ea8-4baa-a978-faffb71ae7c0%40googlegroups.com
> <https://groups.google.com/d/msgid/cp2k/530c0a66-9ea8-4baa-a978-faffb71ae7c0%40googlegroups.com?utm_medium=email&utm_source=footer>
> .
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20191015/4f70fbc1/attachment.htm>