[QE-users] convergence issue in DFT_U+V calculation

Dr. K. C. Bhamu kcbhamu85 at gmail.com
Wed Dec 1 06:07:04 CET 2021


Dear Iurii,
This is from the calculation without nbnd in QE input file (QE input and HP
input are supplied at the end of this email).
I am trying to get a converged value of U+V. Up to four steps, all the
calculations seem to be fine (other than the converged value of U+V). But
in the 5th step, I see that my calculations are not converging.

I am getting this message:
      atom #  5   q point #   3   iter # 180
      chi:   1 -83.8242814567   residue:  103.6191835332
      chi:   2 -83.8242814548   residue:  103.6191835384
      chi:   3 **************   residue:  381.0626501229
      chi:   4 **************   residue:  326.7198566114
      chi:   5 317.5473216386   residue:  329.6382092529
      chi:   6 **************   residue:  580.5784405595
      chi:   7   9.0496504843   residue:    1.9763844786
      chi:   8  -6.2884312048   residue:   21.8495062869
      chi:   9   9.0496505082   residue:    1.9763845088
      chi:  10  -6.2884312084   residue:   21.8495062832
      chi:  11  10.2338160751   residue:    7.3557134894
      chi:  12  -5.1687829951   residue:   22.9825921172
      chi:  13   6.7503553298   residue:    7.1360232476
      chi:  14  -3.9982889995   residue:   27.0388948104
      Average number of iter. to solve lin. system:   23.6
      Total CPU time : 63284.6 s
###################
      atom #  5   q point #   3   iter # 274
      chi:   1 **************   residue:  **************
      chi:   2 **************   residue:  **************
      chi:   3 **************   residue:  **************
      chi:   4 **************   residue:  **************
      chi:   5 **************   residue:  **************
      chi:   6 **************   residue:  **************
      chi:   7 **************   residue:   78.8265104616
      chi:   8 190.5140692168   residue:  **************
      chi:   9 **************   residue:   78.8264974402
      chi:  10 190.5140679621   residue:  **************
      chi:  11 **************   residue:  **************
      chi:  12 544.1915326984   residue:  **************
      chi:  13 **************   residue:  **************
      chi:  14 **************   residue:  **************

U+V value from four completed calculations is given below:


site n.  type  label  spin  new_type  new_label  Hubbard U (eV)
  1        1    Fe1     1      1         Fe1        5.1791
  5        2    Fe2    -1      2         Fe2        5.0962
  7        3    O       0      3         O          7.1203

site n.  type  label  spin  new_type  new_label  Hubbard U (eV)
  1        1    Fe1     1      1         Fe1        5.6013
  5        2    Fe2    -1      2         Fe2        4.3164
  7        3    O       0      3         O          7.5401

site n.  type  label  spin  new_type  new_label  Hubbard U (eV)
  1        1    Fe1     1      1         Fe1        5.6013
  5        2    Fe2    -1      2         Fe2        4.3164
  7        3    O       0      3         O          7.5401

site n.  type  label  spin  new_type  new_label  Hubbard U (eV)
  1        1    Fe1     1      1         Fe1        4.4843
  5        2    Fe2    -1      2         Fe2        0.7259
  7        3    O       0      3         O          7.3480


I do not think changing "conv_thr_chi" will help here as the number is
still oscillating in integer values.

What suggestions do you have for this situation?


HP input file:

 &inputhp
   prefix = 'pwscf',
niter_max=300
   outdir = './temp/',
   nq1 = 2, nq2 = 2, nq3 = 2,
   conv_thr_chi = 1.0d-5,
find_atpert = 1
docc_thr=1.d-3
!disable_type_analysis=.true.,
/

QE input file:
&CONTROL
  calculation = 'vc-relax'
  restart_mode='from_scratch',
  etot_conv_thr =   1.4000000000d-04
  forc_conv_thr =   1.0000000000d-04
  outdir = './temp/'
  prefix = 'pwscf'
  pseudo_dir = '~/PPs/jana_2/'
  tprnfor = .true.
  tstress = .true.
  verbosity = 'high'
/
&SYSTEM
  degauss =   0.022
  ecutrho =   320
  ecutwfc =   40
  occupations = 'smearing' ,    smearing = 'mp'
  ibrav = 0
  nat = 14
  nosym = .false.
  ntyp = 3
nspin=2
  starting_magnetization(1) =   0.8
  starting_magnetization(2) =   -0.8
  starting_magnetization(3) =   0.0

  lda_plus_u = .true.,
  lda_plus_u_kind = 2,
  U_projection_type = 'ortho-atomic',
  !Hubbard_V(1,1,1) = 1.d-8
  !Hubbard_V(5,5,1) = 1.d-8
  !Hubbard_V(7,7,1) = 1.d-8
Hubbard_parameters = 'file'


/
&ELECTRONS
  conv_thr =   1.0000000000d-06
  electron_maxstep = 400
  mixing_beta =   1.5000000000d-01
/
&IONS
                ion_dynamics = 'bfgs'
 /
&CELL
/

ATOMIC_SPECIES
Fe1     55.845 Fe.pbe-nd-rrkjus.UPF
Fe2     55.845 Fe.pbe-nd-rrkjus.UPF
O      15.9994 O.pbe-rrkjus.UPF
ATOMIC_POSITIONS (crystal)
Fe1           0.0000000000       -0.0000000000       -0.0000000000
Fe1           0.5000000000        0.0000000000        0.0000000000
Fe1           0.9999999892        0.5000000216       -0.0000000000
Fe1           0.9999999965        0.9999999956        0.5000000115
Fe2           0.3749993721        0.3749993349        0.3750019210
Fe2           0.6250006225        0.6250006532        0.6249981020
O             0.2454868415        0.2454868399        0.2454949640
O             0.7545131845        0.7545131098        0.7545050345
O             0.7635313546        0.2454868399        0.2454949640
O             0.2364686713        0.7545131098        0.7545050345
O             0.2454868307        0.7635313746        0.2454949640
O             0.7545132523        0.2364686217        0.7545050345
O             0.2454908593        0.2454908222        0.7635274591
O             0.7545090629        0.7545091741        0.2364725394

CELL_PARAMETERS (angstrom)
   5.944682649   0.000000000   0.000000000
   2.972341325   5.148246192   0.000000000
   2.972341325   1.716082064   4.853885701

K_POINTS automatic
7 7 7 0 0 0


Regards
Bhamu
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20211201/d7bca045/attachment.html>


More information about the users mailing list