[QE-users] NEB : path length is increasing

Tamas Karpati tkarpati at gmail.com
Wed Oct 21 13:08:02 CEST 2020


Dear Omar,

Hope it helps, just some ideas:
- I could tell more if you would attach the whole input file (ie. the
structures).
- Without knowing the structures only I can give some hints:
  -- Try using smaller PW basis and lower ecutwfc, ecutrho to speed up
your simulation.
  -- When you obtain something more reliable result, you can change
back to the higher basis.
  -- Try leaving opt_scheme at its default value.
  -- For such a reaction (dissociation of such a polarized molecule) you should
     expect a barrier, therefore CI_scheme should be anything except for no-CI.
  -- The best is if you can specify the CI manually in the
CLIMBING_IMAGES section
     (choose the CI_scheme accordingly).
Bests,
  t

On Tue, Oct 20, 2020 at 6:53 PM Omer Mutasim <omermutasim at ymail.com> wrote:
>
> Dear All
> I'm doning NEB for dissociation reaction of SO2 to SO +O. But it is not converging for more than a week, and the path length is increasing.
> Please tell me what is wrong in my input file:
>
> below is the input & output files:
>
> Input file:
>
> BEGIN
> BEGIN_PATH_INPUT
> &PATH
>   restart_mode      = 'restart'
>   string_method     = 'neb',
>   nstep_path        = 800,
>   ds                = 1.D0,
>   opt_scheme        = "broyden",
>   num_of_images     = 7,
>   CI_scheme         = 'no-CI',
>   path_thr          = 0.05D0,
>
> /
> END_PATH_INPUT
> BEGIN_ENGINE_INPUT
> &CONTROL
>     calculation   = "relax"
> prefix = 'SO2_neb'
>     outdir = './outdir'
>     pseudo_dir = '/home/yQE-test/pseudo/'
> restart_mode = 'from_scratch'
>     forc_conv_thr =  1.0e-03
> etot_conv_thr = 1e-04
>     nstep         = 200
>     !tefield = .TRUE
> !dipfield = .TRUE
> /
>
> &SYSTEM
> ibrav = 0
>     ecutrho                   =  270
>     ecutwfc                   =  45
>     nat                       = 111
>     ntyp                      = 4
> occupations='smearing',smearing='gaussian',degauss=0.005
> vdw_corr = 'DFT-D2'
> !edir = 3 , emaxpos = 0.6808, eopreg = 0.08 , eamp = 0.001,
>     nspin = 2
> starting_magnetization(1)=  0.01
>
> /
> &ELECTRONS
>     conv_thr         = 1e-06
>     electron_maxstep = 200
> mixing_mode ='local-TF'
>     mixing_beta      =  0.3
>
> /
>
> &IONS
> /
>
> K_POINTS {automatic}
> 3 3 1 0 0 1
>
> ATOMIC_SPECIES
> Ni 58.69340 Ni.pbe-n-rrkjus_psl.0.1.UPF
> P 30.97376 P.pbe-n-rrkjus_psl.1.0.0.UPF
> S 32.065      S.pbe-n-rrkjus_psl.1.0.0.UPF
> O 15.9999     O.pbe-n-rrkjus_psl.1.0.0.UPF
> CELL_PARAMETERS {angstrom}
>         11.765383541833         0.0000000000         0.0000000000
>        -5.88269177091652        10.1891210324947    0.0000000000
>         0.0000000000         0.0000000000        30.9938690567585
> BEGIN_POSITIONS
> FIRST_IMAGE
> ATOMIC_POSITIONS (angstrom)
> S       -1.181561037   6.155418563  12.124345096
> O       -1.100425541   4.672437254  11.356300976
> O        0.190308001   6.839217965  11.448732238
> Ni      -2.738525121   4.763450297   0.239145520
> Ni       3.139579474   1.358483744   0.232252034
> Ni       3.135766403   8.150575392   0.235327906
> Ni      -4.673593720   8.104467836   1.780118367
> .
> .
> .
> .
>
> output file:
>
> Program NEB v.6.4.1 starts on 16Oct2020 at 11:35:32
>
>      This program is part of the open-source Quantum ESPRESSO suite
>      for quantum simulation of materials; please cite
>          "P. Giannozzi et al., J. Phys.:Condens. Matter 21 395502 (2009);
>          "P. Giannozzi et al., J. Phys.:Condens. Matter 29 465901 (2017);
>           URL http://www.quantum-espresso.org",
>      in publications or presentations arising from this work. More details at
>      http://www.quantum-espresso.org/quote
>
>      Parallel version (MPI), running on    80 processors
>
>      MPI processes distributed on     5 nodes
>      R & G space division:  proc/nbgrp/npool/nimage =      80
>
>      parsing_file_name: input.in
>      Reading input from pw_1.in
>      Message from routine read_upf::
>
>
>      initial path length           = 11.3145 bohr
>      initial inter-image distance  =  1.8857 bohr
>
>      string_method                 =    neb
>      restart_mode                  =    from_scratch
>      opt_scheme                    =    broyden
>      num_of_images                 =    7
>      nstep_path                    =    800
>      CI_scheme                     =    no-CI
>      first_last_opt                =    F
>      use_freezing                  =    F
>      ds                            =    1.0000 a.u.
>      k_max                         =    0.1000 a.u.
>      k_min                         =    0.1000 a.u.
>      suggested k_max               =    0.6169 a.u.
>      suggested k_min               =    0.6169 a.u.
>      path_thr                      =    0.0500 eV / A
>
>      ------------------------------ iteration   1 ------------------------------
>
>      tcpu =      6.2    self-consistency for image   1
>      tcpu =   3675.5    self-consistency for image   2
>      tcpu =   7662.5    self-consistency for image   3
>      tcpu =  11422.7    self-consistency for image   4
>      tcpu =  15346.3    self-consistency for image   5
>      tcpu =  19108.7    self-consistency for image   6
>      tcpu =  22571.1    self-consistency for image   7
>
>      activation energy (->) =  70.216194 eV
>      activation energy (<-) =  71.022062 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92468.8536637           23.505267            F
>          3     -92442.9691259          150.213122            F
>          4     -92406.7311409          330.353055            F
>          5     -92431.0052901          207.333777            F
>          6     -92469.0661237           51.663167            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 11.314 bohr
>      inter-image distance =  1.886 bohr
>
>      ------------------------------ iteration   2 ------------------------------
>
>      tcpu =  26119.7    self-consistency for image   2
>      tcpu =  28731.5    self-consistency for image   3
>      tcpu =  31027.4    self-consistency for image   4
>      tcpu =  34094.2    self-consistency for image   5
>      tcpu =  36988.0    self-consistency for image   6
>
>      activation energy (->) =  22.531451 eV
>      activation energy (<-) =  23.337319 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92469.5101428           22.300995            F
>          3     -92454.4158842           70.627594            F
>          4     -92461.1206812           34.307062            F
>          5     -92464.4669859           46.783708            F
>          6     -92471.4896125           37.765708            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 11.384 bohr
>      inter-image distance =  1.897 bohr
>
>      ------------------------------ iteration   3 ------------------------------
>
>      tcpu =  39172.0    self-consistency for image   2
>      tcpu =  41888.0    self-consistency for image   3
>      tcpu =  44777.8    self-consistency for image   4
>      tcpu =  47642.0    self-consistency for image   5
>      tcpu =  50615.2    self-consistency for image   6
>
>      activation energy (->) =  13.435341 eV
>      activation energy (<-) =  14.241209 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92471.6434742           16.119604            F
>          3     -92463.5119937           28.367753            F
>          4     -92468.1466546           16.740841            F
>          5     -92472.7705146           11.019872            F
>          6     -92475.3040517           10.662908            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 11.502 bohr
>      inter-image distance =  1.917 bohr
>
>      ------------------------------ iteration   4 ------------------------------
>
>      tcpu =  53323.8    self-consistency for image   2
>      tcpu =  56077.9    self-consistency for image   3
>      tcpu =  59014.9    self-consistency for image   4
>      tcpu =  61990.6    self-consistency for image   5
>      tcpu =  64608.8    self-consistency for image   6
>
>      activation energy (->) =   6.530687 eV
>      activation energy (<-) =   7.336554 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92474.0378392            7.910468            F
>          3     -92470.4166483           13.061889            F
>          4     -92471.2528453            9.923078            F
>          5     -92474.2165523            4.209611            F
>          6     -92476.2787664            3.450159            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 11.724 bohr
>      inter-image distance =  1.954 bohr
>
>      ------------------------------ iteration   5 ------------------------------
>
>      tcpu =  67273.9    self-consistency for image   2
>      tcpu =  70152.2    self-consistency for image   3
>      tcpu =  73153.1    self-consistency for image   4
>      tcpu =  76203.5    self-consistency for image   5
>      tcpu =  78824.8    self-consistency for image   6
>
>      activation energy (->) =   3.710859 eV
>      activation energy (<-) =   4.516727 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92475.5387437            3.615458            F
>          3     -92473.5622985            4.695416            F
>          4     -92473.2364760            5.734324            F
>          5     -92474.4833513            2.877608            F
>          6     -92476.4425910            2.876700            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 12.038 bohr
>      inter-image distance =  2.006 bohr
>
>      ------------------------------ iteration   6 ------------------------------
>
>      tcpu =  81355.0    self-consistency for image   2
>      tcpu =  84402.5    self-consistency for image   3
>      tcpu =  87564.5    self-consistency for image   4
>      tcpu =  90568.2    self-consistency for image   5
>      tcpu =  93110.5    self-consistency for image   6
>
>      activation energy (->) =   2.560838 eV
>      activation energy (<-) =   3.366706 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.0900010            1.040106            F
>          3     -92474.7832671            2.988289            F
>          4     -92474.3864972            2.085630            F
>          5     -92474.8266397            1.998808            F
>          6     -92476.6377600            0.667994            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 12.364 bohr
>      inter-image distance =  2.061 bohr
>
>      ------------------------------ iteration   7 ------------------------------
>
>      tcpu =  95248.7    self-consistency for image   2
>      tcpu =  98189.3    self-consistency for image   3
>      tcpu = 101337.9    self-consistency for image   4
>      tcpu = 104423.7    self-consistency for image   5
>      tcpu = 107076.7    self-consistency for image   6
>
>      activation energy (->) =   2.125802 eV
>      activation energy (<-) =   2.931670 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.0736630            1.319140            F
>          3     -92475.4151167            1.955048            F
>          4     -92474.8215329            1.921925            F
>          5     -92475.0627346            2.135695            F
>          6     -92476.7117640            0.696381            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 12.868 bohr
>      inter-image distance =  2.145 bohr
>
>      ------------------------------ iteration   8 ------------------------------
>
>      tcpu = 108885.3    self-consistency for image   2
>      tcpu = 111194.4    self-consistency for image   3
>      tcpu = 113961.2    self-consistency for image   4
>      tcpu = 116506.3    self-consistency for image   5
>      tcpu = 118361.2    self-consistency for image   6
>
>      activation energy (->) =   2.073805 eV
>      activation energy (<-) =   2.879673 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.1622863            0.861666            F
>          3     -92475.4162307            2.192183            F
>          4     -92474.8735300            1.631538            F
>          5     -92475.0684015            1.824977            F
>          6     -92476.7113576            0.606060            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 12.633 bohr
>      inter-image distance =  2.105 bohr
>
>
> .
> .
> .
> .
> .
> .
>   reading file 'SO2_neb.path'
>
>
>      string_method                 =    neb
>      restart_mode                  =    restart
>      opt_scheme                    =    broyden
>      num_of_images                 =    7
>      nstep_path                    =    800
>      CI_scheme                     =    no-CI
>      first_last_opt                =    F
>      use_freezing                  =    F
>      ds                            =    1.0000 a.u.
>      k_max                         =    0.1000 a.u.
>      k_min                         =    0.1000 a.u.
>      suggested k_max               =    0.6169 a.u.
>      suggested k_min               =    0.6169 a.u.
>      path_thr                      =    0.0500 eV / A
>
>      ------------------------------ iteration  26 ------------------------------
>
>      tcpu =      6.2    self-consistency for image   2
>      tcpu =   3713.3    self-consistency for image   3
>      tcpu =   7137.5    self-consistency for image   4
>      tcpu =  10796.2    self-consistency for image   5
>      tcpu =  14447.3    self-consistency for image   6
>
>      activation energy (->) =   0.640765 eV
>      activation energy (<-) =   1.446632 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.3065704            0.250516            F
>          3     -92477.0673165            0.278078            F
>          4     -92476.7787332            0.431860            F
>          5     -92476.4800774            0.453182            F
>          6     -92476.5576488            0.296200            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 17.545 bohr
>      inter-image distance =  2.924 bohr
>
>      ------------------------------ iteration  27 ------------------------------
>
>      tcpu =  18237.5    self-consistency for image   2
>      tcpu =  20736.0    self-consistency for image   3
>      tcpu =  23008.1    self-consistency for image   4
>      tcpu =  25721.8    self-consistency for image   5
>      tcpu =  28310.3    self-consistency for image   6
>
>      activation energy (->) =   0.643277 eV
>      activation energy (<-) =   1.449145 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.3040583            0.235899            F
>          3     -92477.0080434            0.474599            F
>          4     -92476.8143156            0.678632            F
>          5     -92476.4592005            0.597470            F
>          6     -92476.4827638            0.224064            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 18.367 bohr
>      inter-image distance =  3.061 bohr
>
>      ------------------------------ iteration  28 ------------------------------
>
>      tcpu =  30382.0    self-consistency for image   2
>      tcpu =  32498.8    self-consistency for image   3
>      tcpu =  34597.5    self-consistency for image   4
>      tcpu =  37250.7    self-consistency for image   5
>      tcpu =  39649.7    self-consistency for image   6
>
>      activation energy (->) =   0.651733 eV
>      activation energy (<-) =   1.457601 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.2956021            0.236096            F
>          3     -92476.9388664            0.680956            F
>          4     -92476.8025379            0.874373            F
>          5     -92476.3933083            0.734403            F
>          6     -92476.4272820            0.239132            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 19.115 bohr
>      inter-image distance =  3.186 bohr
>
>      ------------------------------ iteration  29 ------------------------------
>
>      tcpu =  41622.7    self-consistency for image   2
>      tcpu =  43787.2    self-consistency for image   3
>      tcpu =  45892.1    self-consistency for image   4
>      tcpu =  48482.6    self-consistency for image   5
>      tcpu =  50617.1    self-consistency for image   6
>
>      activation energy (->) =   0.661553 eV
>      activation energy (<-) =   1.467420 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.2857825            0.249692            F
>          3     -92476.8823826            0.778237            F
>          4     -92476.7843580            1.002202            F
>          5     -92476.3323697            0.748960            F
>          6     -92476.3885082            0.238984            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 19.742 bohr
>      inter-image distance =  3.290 bohr
>
>      ------------------------------ iteration  30 ------------------------------
>
>      tcpu =  52474.3    self-consistency for image   2
>      tcpu =  54679.9    self-consistency for image   3
>      tcpu =  57012.5    self-consistency for image   4
>      tcpu =  59877.3    self-consistency for image   5
>      tcpu =  62490.2    self-consistency for image   6
>
>      activation energy (->) =   0.704760 eV
>      activation energy (<-) =   1.510628 eV
>
>      image        energy (eV)        error (eV/A)        frozen
>
>          1     -92476.9473351            0.023792            T
>          2     -92476.2668397            0.342411            F
>          3     -92476.7810889            0.907920            F
>          4     -92476.7414553            1.153276            F
>          5     -92476.2425749            0.898295            F
>          6     -92476.3370447            0.341313            F
>          7     -92477.7532028            0.024858            T
>
>      path length          = 20.745 bohr
>      inter-image distance =  3.457 bohr
>
>      ------------------------------ iteration  31 ------------------------------
>
>      tcpu =  64431.3    self-consistency for image   2
>      tcpu =  66430.0    self-consistency for image   3
>      tcpu =  68491.4    self-consistency for image   4
>      tcpu =  70987.8    self-consistency for image   5
>
>
>
>
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