Cut-off problrm

[simin pahlavi]

Thank you Matteu 
Thank you very much fir your helpful comment.
As I am supposed to use this DFT calculations for every step of a ab initio 
molecular dynamics, I wonder if I should
go for the heavy smoothing and get reasonable forces or I should be worry 
about convergence and cutoff dependence of minimization?
I appreciate any reply in advance
Simin

On Monday, April 23, 2018 at 10:41:00 PM UTC+2, Matt W wrote:
>
> Sorry, I posted too quickly without really looking at your setup.
>
> The big problem for you is the XC_GRID settings. 
>
>    &XC_GRID
>     XC_SMOOTH_RHO NN50
>     XC_DERIV NN50_SMOOTH
>    &END XC_GRID
>
> You really do not want to be using heavy smoothing, especially for this 
> purpose. These settings (see original paper) help get reasonable forces 
> with a rather low cutoff, but as you increase the cutoff lead to you 
> continuously redefining the XC functional you use (you are smoothing over 
> different areas of real space), so they do not converge.
>
> Try changing to the defaults
>
>    &XC_GRID
>     XC_SMOOTH_RHO NONE
>     XC_DERIV PW
>    &END XC_GRID
>
> you should see at least a significant improvement.
>
> Matt
>
>>
>>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20180424/daf767b2/attachment.htm>