[QE-users] c_bands: eigenvalues not converged

[Tom Demeyere]

Dear users,

I recently changed pseudopotential for my Pt(111) slab calculations (I changed to the USPP one given by SSSP efficiency). I did a vc-relax to get the alat for this pseudopotential and built the surface using ASE. 

The calculation converges quite well (~ 30 steps) but at every step, I have the message:

c_bands:  X eigenvalues not converged

X is usually between 1 and 4, the warning also appears at the last step of the self-consistency. After the first geometry step, it still appears but less frequently. I don’t know if this is a really big issue but I would like to know why it happens.

Here is my input (I use ESM-BC1)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

&CONTROL
  calculation = 'relax'
  etot_conv_thr = 1.0000000000d-05, forc_conv_thr = 5.0000000000d-04
  tprnfor = .true., tstress = .false.
  verbosity = 'high'
/
&SYSTEM
  ibrav = 0
  ecutwfc = 60, ecutrho = 480
  nat = 45, ntyp = 1
  occupations = 'smearing', smearing = 'cold', degauss = 0.01
  assume_isolated = "esm", esm_bc = "bc1"
/
&ELECTRONS
  conv_thr = 1.00d-8
  mixing_mode = "local-TF", mixing_beta = 0.4
/
&IONS
  ion_dynamics = "bfgs"
/
ATOMIC_SPECIES
Pt 195.084 pt_pbe_v1.4.uspp.F.UPF
ATOMIC_POSITIONS angstrom
Pt      -0.28031804       2.02302122      -4.57757447
Pt       2.52286238       2.02302122      -4.57757447
Pt       5.32604281       2.02302122      -4.57757447
Pt       1.12127217       4.45064668      -4.57757447
Pt       3.92445260       4.45064668      -4.57757447
Pt       6.72763302       4.45064668      -4.57757447
Pt       2.52286238       6.87827214      -4.57757447
Pt       5.32604281       6.87827214      -4.57757447
Pt       8.12922324       6.87827214      -4.57757447
Pt      -0.28031804       0.40460424      -2.28878724
Pt       2.52286238       0.40460424      -2.28878724
Pt       5.32604281       0.40460424      -2.28878724
Pt       1.12127217       2.83222970      -2.28878724
Pt       3.92445260       2.83222970      -2.28878724
Pt       6.72763302       2.83222970      -2.28878724
Pt       2.52286238       5.25985516      -2.28878724
Pt       5.32604281       5.25985516      -2.28878724
Pt       8.12922324       5.25985516      -2.28878724
Pt       1.12127217       1.21381273       0.00000000
Pt       3.92445260       1.21381273       0.00000000
Pt       6.72763302       1.21381273       0.00000000
Pt       2.52286238       3.64143819       0.00000000
Pt       5.32604281       3.64143819       0.00000000
Pt       8.12922324       3.64143819       0.00000000
Pt       3.92445260       6.06906365       0.00000000
Pt       6.72763302       6.06906365       0.00000000
Pt       9.53081345       6.06906365       0.00000000
Pt      -0.28031804       2.02302122       2.28878723
Pt       2.52286238       2.02302122       2.28878723
Pt       5.32604281       2.02302122       2.28878723
Pt       1.12127217       4.45064668       2.28878723
Pt       3.92445260       4.45064668       2.28878723
Pt       6.72763302       4.45064668       2.28878723
Pt       2.52286238       6.87827214       2.28878723
Pt       5.32604281       6.87827214       2.28878723
Pt       8.12922324       6.87827214       2.28878723
Pt      -0.28031804       0.40460424       4.57757447
Pt       2.52286238       0.40460424       4.57757447
Pt       5.32604281       0.40460424       4.57757447
Pt       1.12127217       2.83222970       4.57757447
Pt       3.92445260       2.83222970       4.57757447
Pt       6.72763302       2.83222970       4.57757447
Pt       2.52286238       5.25985516       4.57757447
Pt       5.32604281       5.25985516       4.57757447
Pt       8.12922324       5.25985516       4.57757447
K_POINTS automatic
4 4 1 0 0 0
CELL_PARAMETERS angstrom
8.409541279253872  0.000000000000000   0.000000000000000
4.204770639626936  7.282876382007739   0.000000000000000
0.000000000000000  0.000000000000000  40.000000000000000

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

-----------------------------------------
Tom Demeyere MSc
PhD student
Skylaris Research Group
School of Chemistry, University of Southampton