[Pw_forum] init_london Error

[Duy Le]

I don't remember. You can always calculate it easily:
the ratio between C6 (or R0) of Cacbon in mm_dispersion.f90 and in
dft-d3 code will give you an idea how to convert them.
--------------------------------------------------
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 3:19 PM, Vikas Varshney <vv0210 at gmail.com> wrote:
> Dear Duy, All,
> I have converted the R0 from the dftd3.f code to QE code (from Angs to Bohr
> with 1.1 further scaling factor). However, I dont know what is the scaling
> factor that is used for C6 in mm_dispersion.f90. Any insight will be highly
> appreciated.
>
> Best Regards,
>
> Vikas Varshney,
> Computational Materials Scientist,
> Wright-Patterson Air Force Base, Dayton-OH (USA).
>
> On Tue, Jun 21, 2011 at 11:27 AM, Vikas Varshney <vv0210 at gmail.com> wrote:
>>
>> Dear Duy,
>> Thank you very much for the input. I will look into that today itself.
>>
>> Best Regards,
>> Vikas
>>
>> On Tue, Jun 21, 2011 at 10:51 AM, Duy Le <ttduyle at gmail.com> wrote:
>>>
>>> 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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