Which POTCAR should be used for vdW-DF2

Message

huangj3 · #1 Post by **huangj3** » Tue Apr 16, 2013 5:55 pm

I'm trying to run vdW-DF2 calculations. In the INCAR the following lines are added. Note that the GGA tag is set to ML.

LUSE_VDW=.TRUE.
AGGAC=0.0000
GGA=ML
Zab_vdW=-1.8867

I tried both PAW_PBE and PAW_LDA POTCAR files. Both give the following warning messages in the output:

| ADVICE TO THIS USER RUNNING 'VASP/VAMP' (HEAR YOUR MASTER'S VOICE ...):
|
| You enforced a specific xc-type in the INCAR file, |
| a different type was found on the POTCAR file |
| I HOPE YOU KNOW, WHAT YOU ARE DOING

I'd appreciate if you can tell me which POTCAR files should be used for vdW-DF2 calculations.

Thanks a lot.

huangj3

kelum · #2 Post by **kelum** » Wed Apr 17, 2013 10:53 am

Hi,
it's usually OK to use standard PBE POTCARs, there are no special POTCARs generated for the vdW-DF functionals. Since the vdW contribution is calculated for the pseudo density only, using harder POTCARs or POTCARs with more electrons in the valence might increase the accuracy, if necessary. But the errors can be often neglected. See also this thread:

http://cms.mpi.univie.ac.at/vasp-forum/ ... hp?4.11868

best,
jik