[Pw_forum] init_london Error

[Vikas Varshney]

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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