[QE-users] second scf calculation in relax calculation not converging

Coralie Khabbaz khabbaz.coralie at gmail.com
Fri Jul 10 19:13:19 CEST 2020


Hello Duy Le,

Thank you so much for your answer. What do you mean by reasonable forces? I
have performed several scf calculations before and I get energy values that
are consistent.

On Fri, 10 Jul 2020 at 13:08, Duy Le <ttduyle at gmail.com> wrote:

> It could be because of non-realistic structure as a result of relaxation.
> Please check the force in previously converged scf to see if they are
> reasonable. If not you may need to remake the starting structure so it has
> reasonable forces.
>
> Duy Le
> (UCF)
>
> On Fri, Jul 10, 2020 at 12:53 PM Coralie Khabbaz <
> khabbaz.coralie at gmail.com> wrote:
>
>> Also, when I perform scf calculation (and not relaxation), my energy
>> value converges!!
>>
>> On Fri, 10 Jul 2020 at 12:30, Coralie Khabbaz <khabbaz.coralie at gmail.com>
>> wrote:
>>
>>> Hello,
>>>
>>> I am performing a relaxation calculation on my Tungsten nitride (WN)
>>> slab with a methane molecule adsorbed on its surface. My first scf
>>> calculations always converges, but all the other scf calculations keep
>>> oscillating a little bit, like this:
>>>
>>> iteration #107     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  3.2
>>>
>>>      negative rho (up, down):  1.877E+02 1.832E+02
>>>
>>>      total cpu time spent up to now is     6820.6 secs
>>>
>>>      total energy              =  -22310.34633946 Ry
>>>      Harris-Foulkes estimate   =  -22286.51427887 Ry
>>>      estimated scf accuracy    <   36291.44935321 Ry
>>>
>>>      total magnetization       =     0.88 Bohr mag/cell
>>>      absolute magnetization    =    13.09 Bohr mag/cell
>>>
>>>      iteration #108     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  2.0
>>>
>>>      negative rho (up, down):  1.828E+02 1.844E+02
>>>
>>>      total cpu time spent up to now is     6849.8 secs
>>>
>>>      total energy              =  -22482.46538384 Ry
>>>      Harris-Foulkes estimate   =  -22312.40216721 Ry
>>>      estimated scf accuracy    <   36350.61037433 Ry
>>>
>>>      total magnetization       =     0.84 Bohr mag/cell
>>>      absolute magnetization    =    11.93 Bohr mag/cell
>>>
>>>      iteration #109     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  3.0
>>>
>>>      negative rho (up, down):  1.848E+02 1.794E+02
>>>
>>>      total cpu time spent up to now is     6888.4 secs
>>>
>>>      total energy              =  -22531.89474337 Ry
>>>      Harris-Foulkes estimate   =  -22546.66368909 Ry
>>>      estimated scf accuracy    <   34615.41965371 Ry
>>>
>>>      total magnetization       =     0.49 Bohr mag/cell
>>>      absolute magnetization    =     8.33 Bohr mag/cell
>>>
>>>      iteration #110     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  3.5
>>>
>>>      negative rho (up, down):  1.882E+02 1.776E+02
>>>
>>>      total cpu time spent up to now is     6947.2 secs
>>>
>>>      total energy              =  -22697.64012878 Ry
>>>      Harris-Foulkes estimate   =  -22561.26019900 Ry
>>>      estimated scf accuracy    <   35110.57986884 Ry
>>>
>>>      total magnetization       =     1.02 Bohr mag/cell
>>>      absolute magnetization    =     8.80 Bohr mag/cell
>>>
>>>      iteration #111     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  3.0
>>>
>>>      negative rho (up, down):  1.953E+02 1.846E+02
>>>
>>>      total cpu time spent up to now is     6984.5 secs
>>>
>>>      total energy              =  -22595.85493501 Ry
>>>      Harris-Foulkes estimate   =  -22716.54469069 Ry
>>>      estimated scf accuracy    <   35636.87841917 Ry
>>>
>>>      total magnetization       =     1.33 Bohr mag/cell
>>>      absolute magnetization    =    11.84 Bohr mag/cell
>>>
>>>      iteration #112     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  3.0
>>>
>>>      negative rho (up, down):  2.248E+02 1.996E+02
>>>
>>>      total cpu time spent up to now is     7023.3 secs
>>>
>>>      total energy              =  -22958.24642440 Ry
>>>      Harris-Foulkes estimate   =  -22626.00971729 Ry
>>>      estimated scf accuracy    <   38324.66640261 Ry
>>>
>>>      total magnetization       =     1.31 Bohr mag/cell
>>>      absolute magnetization    =    10.12 Bohr mag/cell
>>>
>>>      iteration #113     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  3.0
>>>
>>>      negative rho (up, down):  2.614E+02 2.124E+02
>>>
>>>      total cpu time spent up to now is     7070.7 secs
>>>
>>>      total energy              =  -23388.04862201 Ry
>>>      Harris-Foulkes estimate   =  -23409.72136428 Ry
>>>      estimated scf accuracy    <   40154.38739523 Ry
>>>
>>>      total magnetization       =     1.90 Bohr mag/cell
>>>      absolute magnetization    =    15.87 Bohr mag/cell
>>>
>>>      iteration #114     ecut=    50.39 Ry     beta=0.10
>>>      Davidson diagonalization with overlap
>>>      ethr =  1.00E-02,  avg # of iterations =  3.5
>>>
>>>      negative rho (up, down):  2.824E+02 2.176E+02
>>>
>>>      total cpu time spent up to now is     7120.5 secs
>>>
>>>      total energy              =  -23737.17074269 Ry
>>>      Harris-Foulkes estimate   =  -23665.30705552 Ry
>>>      estimated scf accuracy    <   35266.44456712 Ry
>>>
>>>      total magnetization       =     2.56 Bohr mag/cell
>>>      absolute magnetization    =    16.20 Bohr mag/cell
>>>
>>> *How can I make my scf calculation converge?*
>>>
>>> This is my *input* file:
>>>
>>> &CONTROL
>>>     calculation   = "relax"
>>>     forc_conv_thr =  1.00000e-03
>>>     max_seconds   =  4.32000e+05
>>>     nstep         = 300
>>>     pseudo_dir    =
>>> "/home/coralee/projects/def-jkopysci/coralee/.pseudopot"
>>> /
>>>
>>> &SYSTEM
>>>     a                         =  8.32716e+00
>>>     angle1(1)                 =  0.00000e+00
>>>     angle1(2)                 =  0.00000e+00
>>>     angle2(1)                 =  0.00000e+00
>>>     angle2(2)                 =  0.00000e+00
>>>     b                         =  8.98689e+00
>>>     c                         =  2.52767e+01
>>>     cosab                     =  6.12323e-17
>>>     cosac                     =  6.12323e-17
>>>     cosbc                     = -1.85547e-01
>>>     degauss                   =  2.00000e-02
>>>     ecutrho                   =  4.75221e+02
>>>     ecutwfc                   =  5.03902e+01
>>>     ibrav                     = 12
>>>     nat                       = 53
>>>     nbnd                      = 480
>>>     nspin                     = 2
>>>     ntyp                      = 4
>>>     occupations               = "smearing"
>>>     smearing                  = "gaussian"
>>>     starting_magnetization(1) =  2.00000e-01
>>>     starting_magnetization(2) =  2.00000e-01
>>> /
>>>
>>> &ELECTRONS
>>>     conv_thr          =  1.00000e-05
>>>     diagonalization   = "david"
>>>     electron_maxstep  = 500
>>>     mixing_beta       =  1.00000e-01
>>>     mixing_mode       = "local-TF"
>>>     startingpot       = "atomic"
>>>     startingwfc       = "atomic+random"
>>> /
>>>
>>> &IONS
>>>     ion_dynamics = "bfgs"
>>> /
>>>
>>> &CELL
>>> /
>>>
>>> K_POINTS {automatic}
>>>  2  2  1  0 0 0
>>>
>>> ATOMIC_SPECIES
>>> N      14.00674  N.pbe-n-kjpaw_psl.1.0.0.UPF
>>> W     183.84000  W.pbe-spn-kjpaw_psl.1.0.0.UPF
>>> C      12.01070  C.pbe-n-kjpaw_psl.1.0.0.UPF
>>> H       1.00794  H.pbe-kjpaw_psl.1.0.0.UPF
>>>
>>> ATOMIC_POSITIONS {angstrom}
>>> N       3.203704   2.747410  14.771098
>>> N       7.372735   2.759212  14.776453
>>> N       3.208642  -1.731177  14.774215
>>> N       7.371486  -1.734287  14.777353
>>> W       3.214859   4.922015  14.312292
>>> W       7.369397   4.914334  14.580589
>>> W       3.207301   0.425737  14.576255
>>> W       7.371014   0.424829  14.576439
>>> N       1.113188   5.239676  14.637084
>>> N       5.300454   5.246400  14.637081
>>> N       1.125960   0.744616  14.647342
>>> N       5.289215   0.745329  14.647446
>>> W       1.122438   3.033042  14.425674
>>> W       5.295367   3.033769  14.426077
>>> W       1.124035  -1.452510  14.426388
>>> W       5.289229  -1.455341  14.427007
>>> N       3.210511   5.196004  12.452975
>>> N       7.370831   5.189844  12.478804
>>> N       3.207641   0.696907  12.479359
>>> N       7.371300   0.696480  12.479853
>>> W       3.206497   3.070844  12.536437
>>> W       7.370775   3.078954  12.541331
>>> W       3.207829  -1.415777  12.539146
>>> W       7.371280  -1.416331  12.539239
>>> N       1.125925   3.569153  12.369437
>>> N       5.289946   3.569319  12.367599
>>> N       1.125855  -0.924614  12.368587
>>> N       5.289457  -0.924540  12.368612
>>> W       1.125854   5.677831  12.169785
>>> W       5.290755   5.676885  12.165625
>>> W       1.126115   1.184835  12.168057
>>> W       5.289247   1.185090  12.168067
>>> N       3.207882   3.506729  10.422372  0 0 0
>>> N       7.371462   3.506729  10.422372  0 0 0
>>> N       3.207882  -0.986715  10.422372  0 0 0
>>> N       7.371462  -0.986715  10.422372  0 0 0
>>> W       3.207882   5.716584  10.333236  0 0 0
>>> W       7.371462   5.716584  10.333236  0 0 0
>>> W       3.207882   1.223140  10.333236  0 0 0
>>> W       7.371462   1.223140  10.333236  0 0 0
>>> N       1.126093   6.199382  10.052766  0 0 0
>>> N       5.289672   6.199382  10.052766  0 0 0
>>> N       1.126093   1.705938  10.052766  0 0 0
>>> N       5.289672   1.705938  10.052766  0 0 0
>>> W       1.126093   3.871912  10.000000  0 0 0
>>> W       5.289672   3.871912  10.000000  0 0 0
>>> W       1.126093  -0.621532  10.000000  0 0 0
>>> W       5.289672  -0.621532  10.000000  0 0 0
>>> C       3.206835   4.918476  16.276735  0 0 0
>>> H       2.573835   4.285476  16.909735  0 0 0
>>> H       3.839835   4.285476  15.643735  0 0 0
>>> H       2.573835   5.551476  15.643735  0 0 0
>>> H       3.839835   5.551476  16.909735  0 0 0
>>>
>>>
>>>
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