ph.x currently does not support the three-body terms with the D3 dispersion correction. You can turn it off with the dftd3_threebody tag in pw.x, and follow the three step procedure you outlined in your email. If you want to include the three-body terms, you can use the supercell approach (e.g., phonopy) instead of DFPT with ph.x.
Three-body terms tend to have a pretty small effect in my experience, but that's system-dependent, in principle, and you might want to test it. Refer to the original D3 papers for a discussion. Three-body terms are not used at all in VASP, for reference (but they're hidden in the source code).
I also generally recommend using D3 with BJ damping or D3M/D3M-BJ instead of the standard "zero damping" D3. (dftd3_version flag in pw.x).
Omar A. Ashour UC Berkeley Hello all,
I am currently trying to perform phonon calculation with DFT-D3 correction. Based on what I read from d3hess.x documentation, I believe I can include dispersion effects on vibrational frequencies by: - Relax / Scf calculation
- run d3hess.x
- run ph.x
However, I encounter an error on step2, with the error message being:
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
task # 28
from pbcgdisp : error # 1
Atom displacement not implemented with the threebody term
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
My input file for scf is as follows:
########################################################################## /
&SYSTEM
ntyp = 1
nat = 2
ibrav = 0
ecutwfc = 100
ecutrho = 400
vdw_corr = 'DFT-D3'
/
&ELECTRONS
mixing_mode = 'plain'
mixing_beta = 0.3
/
&IONS
/
&CELL
/
ATOMIC_SPECIES
H 1.008 H.upf
CELL_PARAMETERS angstrom
5.21657500000000 0.00000000000000 0.00000000000000
0.00000000000000 6.04926000000000 0.00000000000000
-6.40884630521040 0.00000000000000 36.38325638013446
##########################################################################
Can someone advise on what could be the possible error? Thanks! -- Best regards, Jing Lian Ng, PhD Student Wang Material Group
|
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
