[Pw_forum] van der Waals density functional

[Michael Sullivan]

Dear all,

It's in the CVS thanks especially to Stefano de Gironcoli and Timo Thonhauser. From what I've gathered, you're suppose to use RPBE pseudopotentials and override the functional using this: input_dft='vdw-df' in &SYSTEM. You'll also need a generate a vdw-df kernel using generate_vdW_kernel_table.x which is found in $espresso/PW

It seems to work ok for me in my optimizations, which JuNoLo can't do but I still haven't had a chance to do all the testing to ensure I don't have any problems.

It seems they're using the method of Soler so you should probably have a look at their paper as well.

>From $espresso/PW/xc_vdW_DF.f90:
This module calculates the non-local correlation contribution to the energy
  !! and potential. This method is based on the method of Guillermo Roman-Perez
  !! and Jose M. Soler described in:
  !!
  !!    G. Roman-Perez and J. M. Soler, PRL 103, 096101 (2009)

  !! henceforth referred to as SOLER. That method is a new implementation
  !! of the method found in:
  !!
  !!    M. Dion, H. Rydberg, E. Schroeder, D. C. Langreth, and
  !!    B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004).
  !!
  !! henceforth referred to as DION. Further information about the
  !! functional and its corresponding potential can be found in:
  !!
  !!    T. Thonhauser, V.R. Cooper, S. Li, A. Puzder, P. Hyldgaard,
  !!    and D.C. Langreth, Phys. Rev. B 76, 125112 (2007).
  !!
  !! A review article that shows many of the applications vdW-DF has been
  !! applied to so far can be found at:
  !!
  !!    D. C. Langreth et al., J. Phys.: Condens. Matter 21, 084203 (2009).

If you want to try JuNoLo, it interfaces with Quantum ESPRESSO and can be found here:
http://www.fz-juelich.de/iff/src/th1/JuNoLo/

As this is CVS code, you might want to do a bit of testing until you feel comfortable that there aren't any issues with this part or one of the other parts the developers have changed or added.

Hope that helps.

Mike Sullivan
Institute of High Performance Computing, Singapore
michael at ihpc.a-star.edu.sg
http://www.sullivan.sg/
http://www.ihpc.a-star.edu.sg/

From: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] On Behalf Of WANG Wei
Sent: Thursday, January 13, 2011 9:47 PM
To: PWSCF Forum
Subject: Re: [Pw_forum] van der Waals density functional

Dear Giuseppe Mattioli,

Thank you for your reply. I mean that the vdW is calculated from first principles [vdW-DF  M. Dion et al., PRL 92, 246401 (2004)]. It will seem to be  implemented in QE 4.3 and no example yet. Thank you!

see QE/Module/funct.f90
  ! Special cases (dft_shortname):

  !              "vdw-df"= "sla+pw+rpb+vdw"    = vdW-DF
  !              "bp"    = "b88+p86"           = Becke-Perdew grad.corr.
  !              "pw91"  = "pw +ggx+ggc"       = PW91 (aka GGA)
  !              "blyp"  = "sla+b88+lyp+blyp"  = BLYP
  !              "pbe"   = "sla+pw+pbx+pbc"    = PBE
  !              "revpbe"="sla+pw+rpb+pbc"     = revPBE (Zhang-Yang)
  !              "pbesol"="sla+pw+psx+psc"     = PBEsol
  !              "hcth"  = "nox+noc+hcth+hcth" = HCTH/120
  !              "olyp"  = "nox+lyp+optx+blyp" = OLYP
  !              "tpss"  = "sla+pw+meta+meta"  = TPSS Meta-GGA
  !              "wc"    = "sla+pw+wcx+pbc"    = Wu-Cohen
  !              "pbe0"  = "pb0x+pw+pb0x+pbc"  = PBE0
  !              "hse"   = "nox+pw+hse+pbc"    = Heyd-Scuseria-Ernzerhof HSE 06
  !              "b3lyp" = "b3lp+vwn+b3lp+b3lp"= B3LYP
  !
  ! References:
  !              vdW-DF  M. Dion et al., PRL 92, 246401 (2004)

Best,
WANG


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