[QE-users] SCF calculation with no convergence
ykhuang at dicp.ac.cn
ykhuang at dicp.ac.cn
Sat Jun 13 07:34:36 CEST 2020
Hello Khabbaz,
As I am just a beginner of QE, I can only share my limited, personal experience with you. Note that convergence is a quite general problem that maybe everyone will confront with, I recommend you to look up QE-forum: https://www.mail-archive.com/users@lists.quantum-espresso.org/.
1. spin-polarized calculation is not easy to converge as non-polarized ones, so if your structure is just built without any primary optimization, I suggest you perform non-polarized optimization first, although it may be of little help on improving convergence.
2. you can try different mixing_mode. In general, as suggested in QE forum, local-TF may work well for heterogeneous system, but that is not always true. Sometimes plain mode (also known as Broyden mixing) works better than local-TF. Also, the higher vacuum region you add, the harder will your system to converge.
3. you can also try different smearing, although gaussian smearing is default and may be the first recommended, sometimes fd smearing can help your system converge faster, but that all depends.
4. you may want to decrease mixing_beta, or modify mixing_dim, to tune the updating rate of density matrix.
5. set diagonalization = 'cg' will be of help but will be slower than Davidson.
6. note that your system has N element. I remember there was a discussion about one certain (old) kind of nitrogen pseudopotential cause convergence failure, maybe you can test different kinds of pseudopotential.
Best regards!
Yike Huang, PhD candidate.
Dalian Institute of Chemical Physics, CAS, China.
-----原始邮件-----
发件人:"Coralie Khabbaz" <khabbaz.coralie at gmail.com>
发送时间:2020-06-13 01:13:33 (星期六)
收件人: users at lists.quantum-espresso.org
抄送:
主题: [QE-users] SCF calculation with no convergence
Hello,
I am doing an scf calculation on a tungsten nitride (WN) slab (catalyst), with a methane molecule 5 Angstrom away from the surface. The energy values are not converging, even after 533 iterations. The energy values are very negative, and then they increase to a positive value then decrease a lot again. Before building the supercell, I had a WN unit cell with 433 K-points. Then, I built the super cell by using a scaling of 333 and miller indices of 100. I tried using K points of 111 and 222 for my super cell, but the calculations didn't converge for both.
This is the input file I am using:
&CONTROL
calculation = "scf"
max_seconds = 1.72800e+05
pseudo_dir = "/home/coralee/projects/def-jkopysci/coralee/.pseudopot"
restart_mode = "from_scratch"
/
&SYSTEM
a = 1.24907e+01
angle1(1) = 0.00000e+00
angle1(2) = 0.00000e+00
angle2(1) = 0.00000e+00
angle2(2) = 0.00000e+00
b = 1.34803e+01
c = 2.52767e+01
cosab = 6.12323e-17
cosac = 6.12323e-17
cosbc = -1.85547e-01
degauss = 1.00000e-02
ecutrho = 2.70000e+02
ecutwfc = 3.00000e+01
ibrav = 14
nat = 113
nspin = 2
ntyp = 4
occupations = "smearing"
smearing = "gaussian"
starting_magnetization(1) = 2.00000e-01
starting_magnetization(2) = 6.00000e-01
starting_magnetization(3) = 0.00000e+00
starting_magnetization(4) = 0.00000e+00
/
&ELECTRONS
conv_thr = 1.00000e-06
diagonalization = "david"
electron_maxstep = 528
mixing_beta = 4.00000e-01
startingpot = "atomic"
startingwfc = "atomic+random"
/
K_POINTS {automatic}
2 2 2 0 0 0
ATOMIC_SPECIES
N 14.00674 N.pbe-n-rrkjus_psl.1.0.0.UPF
W 183.84000 W.pbe-spn-rrkjus_psl.1.0.0.UPF
C 12.01070 C.pbe-n-rrkjus_psl.1.0.0.UPF
H 1.00794 H.pbe-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS {angstrom}
N 2.481849 0.418242 14.837784
N 6.645429 0.418242 14.837784
N 10.809008 0.418242 14.837784
N 2.481849 4.911686 14.837784
N 6.645429 4.911686 14.837784
N 10.809008 4.911686 14.837784
N 2.481849 9.405131 14.837784
N 6.645429 9.405131 14.837784
N 10.809008 9.405131 14.837784
W 2.481849 2.628097 14.748648
W 6.645429 2.628097 14.748648
W 10.809008 2.628097 14.748648
W 2.481849 7.121541 14.748648
W 6.645429 7.121541 14.748648
W 10.809008 7.121541 14.748648
W 2.481849 -1.865347 14.748648
W 6.645429 -1.865347 14.748648
W 10.809008 -1.865347 14.748648
N 0.400059 3.110895 14.468179
N 4.563639 3.110895 14.468179
N 8.727218 3.110895 14.468179
N 0.400059 7.604339 14.468179
N 4.563639 7.604339 14.468179
N 8.727218 7.604339 14.468179
N 0.400059 -1.382549 14.468179
N 4.563639 -1.382549 14.468179
N 8.727218 -1.382549 14.468179
W 0.400059 0.783425 14.415413
W 4.563639 0.783425 14.415413
W 8.727218 0.783425 14.415413
W 0.400059 5.276869 14.415413
W 4.563639 5.276869 14.415413
W 8.727218 5.276869 14.415413
W 0.400059 9.770314 14.415413
W 4.563639 9.770314 14.415413
W 8.727218 9.770314 14.415413
N 2.481849 3.081849 12.630078 0 0 0
N 6.645429 3.081849 12.630078 0 0 0
N 10.809008 3.081849 12.630078 0 0 0
N 2.481849 7.575293 12.630078 0 0 0
N 6.645429 7.575293 12.630078 0 0 0
N 10.809008 7.575293 12.630078 0 0 0
N 2.481849 -1.411595 12.630078 0 0 0
N 6.645429 -1.411595 12.630078 0 0 0
N 10.809008 -1.411595 12.630078 0 0 0
W 2.481849 0.798260 12.540942 0 0 0
W 6.645429 0.798260 12.540942 0 0 0
W 10.809008 0.798260 12.540942 0 0 0
W 2.481849 5.291704 12.540942 0 0 0
W 6.645429 5.291704 12.540942 0 0 0
W 10.809008 5.291704 12.540942 0 0 0
W 2.481849 9.785148 12.540942 0 0 0
W 6.645429 9.785148 12.540942 0 0 0
W 10.809008 9.785148 12.540942 0 0 0
N 0.400059 1.281057 12.260473 0 0 0
N 4.563639 1.281057 12.260473 0 0 0
N 8.727218 1.281057 12.260473 0 0 0
N 0.400059 5.774502 12.260473 0 0 0
N 4.563639 5.774502 12.260473 0 0 0
N 8.727218 5.774502 12.260473 0 0 0
N 0.400059 10.267946 12.260473 0 0 0
N 4.563639 10.267946 12.260473 0 0 0
N 8.727218 10.267946 12.260473 0 0 0
W 0.400059 3.447032 12.207706 0 0 0
W 4.563639 3.447032 12.207706 0 0 0
W 8.727218 3.447032 12.207706 0 0 0
W 0.400059 7.940476 12.207706 0 0 0
W 4.563639 7.940476 12.207706 0 0 0
W 8.727218 7.940476 12.207706 0 0 0
W 0.400059 -1.046412 12.207706 0 0 0
W 4.563639 -1.046412 12.207706 0 0 0
W 8.727218 -1.046412 12.207706 0 0 0
N 2.481849 1.252012 10.422372 0 0 0
N 6.645429 1.252012 10.422372 0 0 0
N 10.809008 1.252012 10.422372 0 0 0
N 2.481849 5.745456 10.422372 0 0 0
N 6.645429 5.745456 10.422372 0 0 0
N 10.809008 5.745456 10.422372 0 0 0
N 2.481849 10.238900 10.422372 0 0 0
N 6.645429 10.238900 10.422372 0 0 0
N 10.809008 10.238900 10.422372 0 0 0
W 2.481849 3.461867 10.333236 0 0 0
W 6.645429 3.461867 10.333236 0 0 0
W 10.809008 3.461867 10.333236 0 0 0
W 2.481849 7.955311 10.333236 0 0 0
W 6.645429 7.955311 10.333236 0 0 0
W 10.809008 7.955311 10.333236 0 0 0
W 2.481849 -1.031577 10.333236 0 0 0
W 6.645429 -1.031577 10.333236 0 0 0
W 10.809008 -1.031577 10.333236 0 0 0
N 0.400059 3.944664 10.052766 0 0 0
N 4.563639 3.944664 10.052766 0 0 0
N 8.727218 3.944664 10.052766 0 0 0
N 0.400059 8.438108 10.052766 0 0 0
N 4.563639 8.438108 10.052766 0 0 0
N 8.727218 8.438108 10.052766 0 0 0
N 0.400059 -0.548780 10.052766 0 0 0
N 4.563639 -0.548780 10.052766 0 0 0
N 8.727218 -0.548780 10.052766 0 0 0
W 0.400059 1.617195 10.000000 0 0 0
W 4.563639 1.617195 10.000000 0 0 0
W 8.727218 1.617195 10.000000 0 0 0
W 0.400059 6.110639 10.000000 0 0 0
W 4.563639 6.110639 10.000000 0 0 0
W 8.727218 6.110639 10.000000 0 0 0
W 0.400059 10.604083 10.000000 0 0 0
W 4.563639 10.604083 10.000000 0 0 0
W 8.727218 10.604083 10.000000 0 0 0
C 10.809008 2.628097 19.750000
H 10.177000 1.997000 20.383000
H 11.443000 1.997000 19.117000
H 10.177000 3.263000 19.117000
H 11.443000 3.263000 20.383000
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