[CP2K:1626] GRIMME and parameters

[Juerg Hutter]

Hi Daniele

> Dear developers
>
> The DFT-D functional[GRIMME 2006] is implemented in the code. The
> example in the regtests refers to the PBE functional. The paper by
> Grimme explains that in principle one could (upon reparametrization of
> the functional) use the pairwise correction terms in connection with
> any functional, and for any element of the periodic table. Eventually,
> the paper seems to refer mostly on PBE and on atoms up to Xe.
>
> So I have two questions:
>
> 1) can I use GRIMME with other functionals in cp2k?

Yes, the default scaling parameters for some functionals from the
Grimme Paper are applied. You can always use your own parameter by
specifying the value in the input. Check the output if the value
used is what you expected.

>
> 2) What does it happen if I include elements that are not present in
> the paper [for example, a hydrocarbon on Gold]?
>

The code should stop if there are no default values and you are not 
defining any values in the input. I just checked and it seems that
instead of stopping the code proceeds with wrong parameters.
We will fix this as soon as possible.
For your problem I suggest that you pick some reasonable values for
Au and set them through the input. Of course in the next step
you should check that those values work as expected.

regards

Juerg



> Thank you in advance,
>
> Daniele Passerone
>
> >
>