[Pw_forum] init_london Error

[Vikas Varshney]

Thank you all of you (Pablo, Stefano and Giuseppe)
It did clarify many of my confusions.

Best Wishes,
Vikas

On Fri, Jul 1, 2011 at 8:30 AM, Giuseppe Mattioli
<giuseppe.mattioli at mlib.ism.cnr.it> wrote:
>
> Dear Vikas
> A final remark:
>
>> I am using GGA functionals
>> for my relaxation. So, as you mentioned vdw-DF is improved for LDA
>> type of functionals, I will stick with the london option.
>
> The vdW-DF functional is not a simple LDA xc functional. It contains a
> long-range LDA correlation contribution. Some lines extracted from the
> Modules/funct.f90 file may help to explain:
>
>  !              "pz"    = "sla+pz"            = Perdew-Zunger LDA
>  !              "pbe"   = "sla+pw+pbx+pbc"    = PBE
>  !              "revpbe"= "sla+pw+rpb+pbc"    = revPBE (Zhang-Yang)
>  !              "vdw-df"= "sla+pw+rpb+vdw"    = vdW-DF
>  !
>  ! Exchange:
>  !              "sla"    Slater (alpha=2/3)
>  !
>  ! Correlation: "noc"    none
>  !              "pz"     Perdew-Zunger
>  !              "pw"     Perdew-Wang
>  !
>  ! Gradient Correction on Exchange:
>  !              "pbx"    Perdew-Burke-Ernzenhof exch
>  !              "rpb"    revised PBE by Zhang-Yang
>  !
>  ! Gradient Correction on Correlation:
>  !
>  !              "pbc"    Perdew-Burke-Ernzenhof corr
>  !
>  ! Van der Waals functionals
>  !              "nonlc"   none
>  !              "vdw1"    vdW-DF1
>  !              "vdw2"    vdW-DF2
>  !
>  ! References:
>  !              pz      J.P.Perdew and A.Zunger, PRB 23, 5048 (1981)
>  !              pbe     J.P.Perdew, K.Burke, M.Ernzerhof, PRL 77, 3865 (1996)
>  !              pw91    J.P.Perdew and Y. Wang, PRB 46, 6671 (1992)
>  !              revPBE  Zhang and Yang, PRL 80, 890 (1998)
>  !              vdW-DF  M. Dion et al., PRL 92, 246401 (2004)
>  !                      T. Thonhauser et al., PRB 76, 125112 (2007)
>
> Yours
> Giuseppe
>
> On Friday 01 July 2011 09:49:54 Stefano de Gironcoli wrote:
>> vdW-DF is not yet implemented in the DFPT part.
>> we are working on that,
>> stefano
>> -
>> Stefano de Gironcoli - SISSA and DEMOCRITOS
>>
>> On 07/01/2011 09:45 AM, Paolo Giannozzi wrote:
>> > On Thu, 2011-06-30 at 12:36 -0400, Vikas Varshney wrote:
>> >> Lets say for my system of interest, I want to use LDA functionals with
>> >> vdw-DF setting (which will modify the wavefunctions) and run an SCF
>> >> calculation on a previously relaxed geometry. Then, I do the phonon
>> >> dispersion calculation (...). In that case, will the calculated
>> >> dynamical matrix include the interactions from vdw forces as well?
>> >
>> > only in part, because you will start from vdw-aware wavefunctions,
>> > but you will miss the vdw term in the second derivative of the
>> > exchange-correlation functional. I just heard rumors that this
>> > will be soon implemented, though
>> >
>> > P.
>>
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>
>
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>    Giuseppe Mattioli
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