[QE-users] Phonon calculation with DFT-D3 correction

[Ghosh, Prasenjit]

Alternatively, you can calculate using the frozen phonon method. 

Prasenjit 
IISER Pune 


From: "users" <users at lists.quantum-espresso.org> 
To: "users" <users at lists.quantum-espresso.org> 
Sent: Wednesday, May 15, 2024 3:49:18 AM 
Subject: Re: [QE-users] Phonon calculation with DFT-D3 correction 

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 



On May 14, 2024, at 2:51 PM, Jing Lian Ng <jinglian at utexas.edu> wrote: 





BQ_BEGIN

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: 


    1. Relax / Scf calculation 
    2. run d3hess.x 
    3. 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 University of Texas at Austin | [ http://che.utexas.edu/ | McKetta Department of Chemical Engineering ] | [ https://wangmaterialsgroup.com/ | Wang Materials Group ] 
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_______________________________________________ 
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 
_______________________________________________ 
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