vdW DF2 functional

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!!

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

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

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).

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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!

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