[Pw_forum] init_london Error

[Duy Le]

Dear Vikas,
One simplest thing you can do is to read the DFT-D2 part of DFT-D3
code provided by Grimme's group (http://toc.uni-muenster.de/DFTD3/)
You will be able to find all necessary coefficients for all atoms with
Z<=86. Then you have to add them to mm_dispersion.f90. Recompile QE,
then you are good to go.
--------------------------------------------------
Duy Le
PhD Candidate
Department of Physics
University of Central Florida.

"Men don't need hand to do things"



On Tue, Jun 21, 2011 at 10:40 AM, Vikas Varshney <vv0210 at gmail.com> wrote:
> Dear All,
>
> I am trying to relax my WS2 unit cell structure using vc-relax (using PBE
> pps) and I want to include disperson corrections to it. So, I tried using
> the london flag = .true. However, on starting my job I got an error
>
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>      from  init_london  : error #         1
>      atom W   not found
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
> After going through mm_dispersion.f90, I found that the vdw_radius and c_6
> parameters are given for first 54 atoms only (which corresponds to first 5
> periods of periodic table). Tungsten (W), with atomic number of 74 is in 6th
> period.
>
> I emailed Prof. Stefan Grimme (author of the references that are mentioned
> in mm_dispersion.f90) if anything was further pursued. He replied mentioning
> that they have approached this problem further and referred me to his
> website,
>
> http://toc.uni-muenster.de/DFTD3/
>
> and told me that this has already been implemented into major QM codes.
>
> Mentioning that, I have few questions.
> 1. I wanted to ask if QE has incorporated the additions DFT-D, recently.
> 2. Are there any other ways to incorporate dispersion interactions in
> calculations in DFT.
>
> Currently, I am running my simulations on 4.2 version of the code that I
> downloaded few months ago. I would high appreciate your insights in how
> should I go about solving this problem regarding dispersion interactions in
> Tungsten.
>
> Looking forward for a positive reply.
>
> Best Regards,
>
> Vikas Varshney,
> Computational Materials Scientist,
> Wright-Patterson Air Force Base, Dayton-OH (USA).
>
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