Are you sure that the atoms positions are correct? Very close atoms can
cause convergence problems. I would check with xcrysden, or the
online-tool seekpath, or with dist.x
cheers
On 18/07/2022 15:45, Connor Wilson wrote:
Hi everyone,
I am trying to obtain a converged SCF calculation (using Quantum
ESPRESSO, version 7.0) for the medium-entropy oxide (CoCuMgZn)_0.25
O. This material crystalizes in the rocksalt structure. I am using a
64-atom supercell. I have attached my input file at the end of this
message.
My problem is: after 50 iterations, my calculations show no trend
towards convergence (ie. the 'estimated scf accuracies' in the pw.x
output file stabilize around 0.5 Ry). I have made the following
adjustments in an effort to achieve better convergence:
* using degauss values of 0.001, 0.01, 0.02
* using a 6 x 6 x 6 K-mesh
* using mixing_beta of 0.05, 0.1, 0.2
* using ecutwfc of 60, 70, 100 (each with 10x ecutrho)
* using PBEsol, PBE pseudopotentials
My question is: do you think it is possible to achieve a converged SCF
calculation using QE? If it is, what might an appropriate value of
conv_thr be, and could you suggest other changes to my input file I
could try?
Thank you for your time,
Connor Wilson
Brock University
Department of Mathematics and Science
1812 Sir Issac Brock Way, St. Catharines, ON, CAN, L2S 3A1
######################## pw.x input ###########################
&CONTROL
calculation = 'scf',
prefix = 'MEO',
tstress = .true.,
tprnfor = .true.,
restart_mode = 'from_scratch',
outdir = '/home/cw279/projects/def-crandles/cw279/MEO/222c/alat'
pseudo_dir = '/home/cw279/pseudo',
/
&SYSTEM
ibrav = 1,
celldm(1) = 15.1,
nat = 64,
ntyp = 5,
ecutwfc = 100,
ecutrho = 1000,
occupations = 'smearing',
smearing = 'mv',
degauss = 0.01,
/
&ELECTRONS
electron_maxstep = 50,
mixing_beta = 0.1,
conv_thr = 1.0d-6,
mixing_mode = 'local-TF',
mixing_ndim = 10,
/
ATOMIC_SPECIES
Mg 24.305 Mg.pbe-spnl-kjpaw_psl.1.0.0.UPF
O 15.9994 O.pbe-n-kjpaw_psl.1.0.0.UPF
Zn 65.380 Zn.pbe-dnl-kjpaw_psl.1.0.0.UPF
Ni 58.6934 Ni.pbe-spn-kjpaw_psl.1.0.0.UPF
Co 58.9332 Co.pbe-spn-kjpaw_psl.0.3.1.UPF
K_POINTS {automatic}
4 4 4 0 0 0
ATOMIC_POSITIONS {crystal}
........
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Dr. Lorenzo Paulatto
IdR @ IMPMC - CNRS UMR 7590 & Sorbonne Université
phone: +33 (0)1 442 79822 / skype: paulatz
http://www.impmc.upmc.fr/~paulatto/ - https://anharmonic.github.io/
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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
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users@lists.quantum-espresso.org
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