vdW DF2 functional

Running Abinit Response calculations
1

In the old forum there was a topic:

Availability of vdW-DF1/2 functionals

The last posting was in 2018:
st by cespejo » Thu Sep 13, 2018 2:51 pm

Hi Ron, I hope that vdW-DF1/2 functionals will be working for the start of the 8.11.1 version. This is in one month.

Cheers,

Camilo

I am trying to run now after years on abinit again, and I was shocked to get:

— !ERROR
src_file: m_rhotoxc.F90
src_line: 1229
mpi_rank: 382
message: |
vdW-DF functionals are not fully operational yet.
Action : modify vdw_xc
…

ABINIT 9.4.1

Is there any way to use df2 functionals? I need to be able to use all response functions, applied fields, etc, and the system is also spin polarized.

Thanks for any help!!

1 Like
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Hi Ron,

good point - I will ping @pouillon and @cespejo to see what their status is. I have only seen DFPT with DF2 described in a thesis online for QE. @Benoit_Van_Troeye told me it would not be too hard to add, and easier than what he did for Grimme D3.

Best

Matthieu

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Hi Ron and Matt,
I’m really sorry that vdW-DF is still not working :pray:t4:. Currently we are stuck with an issue regarding 3D FFTs. I had to slow down the development and debugging of vdW-DF last year but I’ve resumed it a couple of months ago. I hope this implementation will be usable by the end of the year, however you will know if it is ready before.
I agree with @Benoit_Van_Troeye since the vdW-DF quantities are computed and added within the SCF cycle,so all the DFPT machinery can be operated as usual…the computations will be more time consuming though. (@mverstra: I’ll search for that thesis!)

Best,
Camilo

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https://journals.aps.org/prb/pdf/10.1103/PhysRevB.93.235120
https://iris.sissa.it/handle/20.500.11767/4710#.YR0fcS1h1TY

But I am not sure if it is in their release version of QE (after all these years).

2 Likes
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I would be very glad to try the new code as soon as available. I am getting some strange behavior from QE with LR in spin-polarized systems, and since I have vdW and spin it is a mess! Unfortunately I have been stymied by other codes–cp2k has DF2 but no linear response, CASTEP doesn’t do spin-polarized linear response and doesn’t have non-local DF functionals, QE in principle should work but in practice is giving strange results, and abinit would be great! I hope it will work with spin-polarization as well. What I need is effective charges, so supercell methods will not help. Thank you so much for working on this!

1 Like
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Thanks a lot @mverstra! For some reason I did not get a notification when you replied :frowning:

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Hi! I wonder what is the status now of DF2. Any progress? Also, will it work with spin-orbit? In QE DF1 non-local vdW like DF2 doesn’t work with spin-orbit. Thanks! Ron

Ronald Cohen
Extreme Materials Initiative
Carnegie Institution for Science
5251 Broad Branch Rd., N.W.
Washington, D.C. 20015
rcohen@carnegiescience.edu

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Time marches on! Any progress on df2?

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Hi Ron.
Currently vdW-DF1(2) is working for non-self consistent calculations (for a given electronic density the vdW energy is correct). Progress is ongoing to solve the issues related to the SCF vdW-DF calcs.

All the best,
Camilo