[Pw_forum] vdW force in mm_dispersion.f90 and Van der Waals functional

[Stefano de Gironcoli]

Dear Yukihiro Okuno,

     by symmetry the DFT-D contribution to the forces on atom na due to 
its periodic images is zero.

     As said previously forces and stress are implemented within vdW-DF.
     Actually forces need no specific implementation as via 
Hellmann-Feynman theorem only derivatives of the external potential is 
needed. Stress has been implemented (by Riccardo Sabatini in SISSA) and 
is currently in the cvs version.

stefano

On 02/09/2011 02:31 AM, Emine Kucukbenli wrote:
> Dear Yukihiro Okuno,
> I don't know about the mm_dispersion part, however, as far as I know,
> reliable force&stress calculations with the vdW-DF are implemented in
> the CVS version.
>
> emine kucukbenli, phd student, sissa, italy
>
> Quoting yukihiro_okuno at fujifilm.co.jp:
>
>>
>> And  in CVS version of PWSCF implementation of  vdW functional in vDW_DF
>> Modules,
>>
>> it seems there is a stress calculation function, but still  no force
>> calculation function
>>
>> within non-local vdW functional.  Are there plan to implement the force
>> from vdW
>>
>> interaction within SCF scheme.
>>
>>
>> Sincerely.
>>
>> Yukihiro Okuno.
>>
>
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