[Pw_forum] Re: vanderwaals

[Nichols A. Romero]

Sandro (or anyone else for that matter),

Are there any examples files showing how to us the empirical vdW
within CP? I assume there wouldn't be any issue using it in
conjunction with any of the other capabilities of CP, e.g. NVT,
variable-cell MD, BO MD, etc.

On 4/11/06, Sandro Scandolo <scandolo at ictp.it> wrote:
> Nichols,
>
> unfortunately this is not the vdW functional of Langreth et al.
>
> It is a much simpler procedure to correct the DFT forces and stress
> for the missing 1/R^6 tail. It consists of adding to the DFT forces
> and stress a classical interatomic force field that decays at long
> distances like 1/R^6 (with the appropriate C6 coefficients), and
> vanishes at "short" distances, i.e. at interatomic distances where
> one expects DFT to give the correct forces. This is done in a smooth
> fashion, of course. It requires a cut-off distance, a smoothing
> parameter, and the C_ij coefficients for any pair i,j of species.
> The present implementation is system-specific (for a C-H saturated
> system) but can trivially be extended for any system. More details
> can be found in S. Serra et al, Chem Phys Lett 331, 339 (2000)
>
> Regards,
> Sandro
>
> *
>
> From: Nichols A. Romero* <mailto:pw_forum%40pwscf.org>
> /Mon, 3 Apr 2006 10:46:19 -0400/
>
> Hi,
>
> In CP source, there is a file called
> vanderwaals.f90
>
> Is this the vdW functional of D. Langreth et. al?
>
> Bests,
> --
> Nichols A. Romero, Ph.D.
> 1613 Denise Dr. Apt. D
> Forest Hill, MD 21050
> 443-567-8328 (C)
> 410-306-0709 (O)
>
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--
Nichols A. Romero, Ph.D.
1613 Denise Dr. Apt. D
Forest Hill, MD 21050
443-567-8328 (C)
410-306-0709 (O)