[Pw_forum] combining vdW-DF and hybrids?

[Giuseppe Mattioli]

Dear José-Carlos
I'm involved in studies of molecules interacting with metal oxide surfaces 
too, so I face problem similar to yours. I know that the Grimme trick is not 
the best thing, but you can change by hand the C6 coefficients following some 
molecular mechanics force field (AMBER, CHARMM...). Anyway your calculations 
will be VERY cpu-consuming, even if you sample the BZ with gamma only...
Yours

Giuseppe
 
On Tuesday 15 February 2011 16:57:59 Jose C. Conesa wrote:
> Hi,
> Thanks for the suggestion, but it does not help me. I'm not concerned
> only with molecules, but with oxide layer compounds and surfaces as
> well; and for these the standard Grimme's parameters are not adequate
> (see J Phys Chem C _114_(2010)22718). For this I should like to try
> hse06 and vdW-DF together, but it's not clear if Q-E allows it.
>
> José-Carlos
>
> El 15/02/2011 6:06, Giuseppe Mattioli escribió:
> > I would only add a perhaps useless suggestion.
> > If you are dealing with molecules and your main interest is in using the
> > HSE06 functional, then try to use the london=.true. keyword. The
> > semiempirical london correction behaves well with molecules and could fit
> > to your system. HTH
> >
> > Giuseppe
> >
> > On Saturday 12 February 2011 13:46:26 CONESA CEGARRA, JOSE CARLOS wrote:
> >> hi,
> >>
> >> I am doing some tests with the cvs version of Q-E. I wonder, could one
> >> combine the HSE06 functional (that refers only to exchange) with the
> >> vdw-DF correlation? I tried a line such as input_dft='nox+pw+hse+vdw'
> >>
> >> but got a message of incompatibility of functionals.
> >>
> >> Also, some question to the developers:
> >>
> >> a) is there work for allowing soon the use of hybrid functionals with
> >> USPP or PAW potentials?
> >>
> >> b) will the vdW-DF2 functional be available (with both ions and cell
> >> relaxation, if possible) in the 4.3 version?
> >>
> >> All the best,



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   Giuseppe Mattioli                            
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