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

Duy Le ttduyle at gmail.com
Fri Jul 10 19:07:58 CEST 2020


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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