[QE-users] Query regarding vdW-DF2 functional

[Lorenzo Paulatto]

Just reduce the amount of vacuum: if you have too much of it, one 
electron may decide to wandr of and cause all sort of troubles. Between 
6 and 8 Å should be enough. Also, as Paola said, grimme-d2 cannot be the 
cause as it is a purely ion-ion term.



On 9/21/20 1:12 PM, Dhvaneel Visaria wrote:
> Hello Lorenzo Paulatto,
> 
> Thank you for your prompt reply.
> 
> I am still NOT able to achieve convergence for ph.x using vdW-DF2 even 
> after using finer k-point grids of 16x16x1 and 32x32x1, while this 
> convergence issue did not arise for no vdW functional & Grimme-D2 cases 
> with 12x12x1 k-point grid. The output files for the above cases can be 
> found here 
> <https://drive.google.com/drive/folders/1KVlLz6SoTpTdxcviNTyEvMAKrOJb1ZyM?usp=sharing>.
> 
> What could be the problem?
> 
> Thanks & Regards,
> Dhvaneel Visaria
> IIT Bombay
> 
> On Mon, 21 Sep 2020 at 15:02, Lorenzo Paulatto <paulatz at gmail.com 
> <mailto:paulatz at gmail.com>> wrote:
> 
>      >   K_POINTS automatic
>      >    12 12 1 0 0 0
>      >
>     k-point grid which have a dimension multiple of 3 are a frequent cause
>     of troubles for graphene. Also, this is probably too coarse.
> 
>     hth
> 
>     -- 
>     Lorenzo Paulatto - Paris
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Lorenzo Paulatto - Paris