Dear Arles,

Thanks for your answer. I'm using the GBRV pseudopotentials family, in which the authors indicate that "In particular, the GBRV potentials are designed to run at a plane-wave cutoff of 40 Ry and a charge-density cutoff of 200 Ry..." [Comp Mat Sci 81 (2104) 446). I agree that the systems tested by the authors do not include TM complexes, so, probably, I cannot expect a good transferability for PS, so this could be the error's source. I'll investigate this issue.

Regards,

Reinaldo

On 01/06/18 11:47, Arles V. Gil Rebaza wrote:
Dear Reinaldo, are you sure that these values of ecutwfc =  40 and  ecutrho  = 200 describe your system well? Probabily you should increase these values, in order to describe the transition metal atom (Cu) and the total energy (forces and pressure depends of the  total energy). Try to converge the total energy of the system respect to ecutwfc value performing self-consistent calculation for different vaues of ecutwfc. Furthermore, for US pseudopotential the ecutrho value is tipically 8 to 12 times ecutwfc (see QE manual).

Best

Dr. Arles V. Gil Rebaza
Instituto de Física La Plata
La Plata - Argentina.

2018-06-01 11:20 GMT-03:00 Reinaldo Pis Diez <reinaldo.pisd...@gmail.com <mailto:reinaldo.pisd...@gmail.com>>:

    Dear folks,

    I usually help some experimentalist fellows from the Center I
    belong by calculating geometries, cell parameters, vibrational
    frequencies, electronic transitions, etc, of transition metal
    complexes. As the cif file is often available, I use it to
    create the input file for PWScf using Virtual Nano Lab from
    Quantum Wise.

    Although convergence of the vc-relax job is usually achieved,
    some cases are more problematic. Job ends with a high pressure
    and with atomic forces far from thresholds when 'bfgs' is used
    both for &ions and &cell namelists. Using 'damp' does not help
    to get geometry and cell parameters optimized. Thus my (very
    general) question is: does anybody know an strategy to
    systematically get convergence when doing vc-relax? A link to
    a tutorial or a document is welcome.

    For completeness, the input of one of the problematic cases is
    appended below. By the way, I'm using "Program PWSCF v.6.1
    (gpu tag v1.0)" compiled with PGI compilers and MKL libraries
    on a CentOS box with a Titan X (Pascal) gpu.

    Thanks in advance

    Reinaldo
    Center of Inorganic Chemistry
    Natl Univ of La Plata, Argentina

    Input follows....

    &CONTROL
     title         = 'Cu-ovatpnh2'
     calculation   = 'vc-relax'
     restart_mode  = 'from_scratch'
     outdir        = './'
     pseudo_dir    = './'
     prefix        = 'Cu-ovatpnh2'
     etot_conv_thr = 0.0001
     forc_conv_thr = 0.0004
     tstress       = .true.
     tprnfor       = .true.
     nstep         = 200
    /

    &SYSTEM
      ibrav       = 14
      celldm(1)   = 9.9320792573d0
      celldm(2)   = 2.0161515879d0
      celldm(3)   = 2.1156030541d0
      celldm(4)   = -0.1705259449d0
      celldm(5)   = -0.0219091103d0
      celldm(6)   = -0.2238523262d0
      nat         =  59
      ntyp        =   6
      ecutwfc     =  40
      ecutrho     = 200
      input_dft   = 'pbe'
      occupations = 'smearing'
      smearing    = 'mv'
      degauss     = 0.005
      nspin       = 2
      starting_magnetization(1) = 0.7
    /

    &ELECTRONS
      conv_thr        = 1d-06
      mixing_beta     = 0.6
      mixing_mode     = 'plain'
      mixing_ndim     = 8
      diagonalization = 'david'
    /

    &IONS
     ion_dynamics = 'bfgs'
    /

    &CELL
     cell_dynamics = 'bfgs'
     press         = 0.5
    /

    ATOMIC_SPECIES
      Cu 63.546000d0 cu_pbe_v1.2.uspp.F.UPF
      C  12.010700d0  c_pbe_v1.2.uspp.F.UPF
      H   1.007940d0  h_pbe_v1.4.uspp.F.UPF
      N  14.006700d0  n_pbe_v1.2.uspp.F.UPF
      O  15.999400d0  o_pbe_v1.2.uspp.F.UPF
      S  32.065000d0  s_pbe_v1.4.uspp.F.UPF

    ATOMIC_POSITIONS (crystal)
    C        0.082231085   0.204570350   0.616545553
    C        0.917768915   0.795429650   0.383454447
    C        0.172973917   0.203448044   0.733466608
    C        0.827026083   0.796551956   0.266533392
    H        0.367673209   0.258122966   0.770942028
    H        0.632326791   0.741877034   0.229057972
    C        0.987334077   0.125087827   0.797766960
    C        0.012665923   0.874912173   0.202233040
    H        1.019591574   0.112838755   0.892010655
    H       -0.019591574   0.887161245   0.107989345
    C        0.756454381   0.067986708   0.729401520
    C        0.243545619   0.932013292   0.270598480
    H        0.580696185   0.004985342   0.755622580
    H        0.419303815   0.995014658   0.244377420
    C        0.224564542   0.266351629   0.518206870
    C        0.775435458   0.733648371   0.481793130
    H        0.388829444   0.346391746   0.560989945
    H        0.611170556   0.653608254   0.439010055
    H        0.304022379   0.192372172   0.457292153
    H        0.695977621   0.807627828   0.542707847
    C        0.956901991   0.245893003   0.340167231
    C        0.043098009   0.754106997   0.659832769
    H        0.022416710   0.153595990   0.313033710
    H        0.977583290   0.846404010   0.686966290
    C        0.771131988   0.269306261   0.255617666
    C        0.228868012   0.730693739   0.744382334
    C        0.652850645   0.378765293   0.282708985
    C        0.347149355   0.621234707   0.717291015
    C        0.462994923   0.392175655   0.192940332
    C        0.537005077   0.607824345   0.807059668
    C        0.403148927   0.302768506   0.084001267
    C        0.596851073   0.697231494   0.915998733
    H        0.259814627   0.314740185   0.016757517
    H        0.740185373   0.685259815   0.983242483
    C        0.525750373   0.196269824   0.058490144
    C        0.474249627   0.803730176   0.941509856
    H        0.478830729   0.128376775   0.971151210
    H        0.521169271   0.871623225   0.028848790
    C        0.705969389   0.179966480   0.142934709
    C        0.294030611   0.820033520   0.857065291
    H        0.804698818   0.098652977   0.124221693
    H        0.195301182   0.901347023   0.875778307
    C        0.184454672   0.523754793   0.135830920
    C        0.815545328   0.476245207   0.864169080
    H        0.287576875   0.544363666   0.053314825
    H        0.712423125   0.455636334   0.946685175
    H        0.118308380   0.611071476   0.178999457
    H        0.881691620   0.388928524   0.821000543
    H        0.013394359   0.440437861   0.110093147
    H        0.986605641   0.559562139   0.889906853
    N        0.053284394   0.319764373   0.444382321
    N        0.946715606   0.680235627   0.555617679
    O        0.705759527   0.466685324   0.381694456
    O        0.294240473   0.533314676   0.618305544
    O        0.356827705   0.498376849   0.225196110
    O        0.643172295   0.501623151   0.774803890
    S        0.766003561   0.110202377   0.587178900
    S        0.233996439   0.889797623   0.412821100
    Cu      -0.000000000   0.500000000   0.500000000

    K_POINTS {automatic}
      3 3 3 0 0 0
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--
Arles V.


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