[Pw_forum] Simulation ends at forces greater than forc_conv_thr

quantum quantum at mail.ncyu.edu.tw
Fri Oct 7 05:25:37 CEST 2016


Dear QE Friends:

I am trying to optimize a crystal by allowing the atomic positions of hydrogens to relax. All other atoms of the crystal are held fixed.  The QE input file is listed by the end of this message.

QE starts with the self-consistent calculation using the initial guess of atomic positions.  After the first scf cycle, QE prints out a new set of atomic positions, and ends without a new scf cycle with the new set of atomic positions. (Please see the QE output attached below.)

The EQ output suggests that the forces acting on all hydrogen atoms are greater than "forc_conv_thr = 1.0D-4."   

Why does the simulation end with only one scf cycle?

Thank you in advance.


**** QE output file (partial) starts here ******************

!    total energy              =   -1426.31830754 Ry
     Harris-Foulkes estimate   =   -1426.31830738 Ry
     estimated scf accuracy    <       0.00000009 Ry

     The total energy is the sum of the following terms:

     one-electron contribution =    -615.01611222 Ry
     hartree contribution      =     407.92628821 Ry
     xc contribution           =    -287.90966771 Ry
     ewald contribution        =    -702.94572199 Ry
     Dispersion Correction     =      -0.28187072 Ry
     one-center paw contrib.   =    -228.09122311 Ry

     convergence has been achieved in   9 iterations

     Forces acting on atoms (Ry/au):

     atom    1 type  1   force =     0.00000104   -0.00894702   -0.00000051
     atom    2 type  1   force =    -0.00000045   -0.00894443   -0.00000014
     ........
     atom   33 type  4   force =    -0.01684128   -0.06271162    0.16881369
     atom   34 type  4   force =    -0.01684137   -0.06271191    0.16881443
     atom   35 type  4   force =    -0.01684128    0.06271162    0.16881368
     atom   36 type  4   force =    -0.01684137    0.06271191    0.16881444
     atom   37 type  4   force =     0.01684128   -0.06271162   -0.16881368
     atom   38 type  4   force =     0.01684137   -0.06271191   -0.16881444
     atom   39 type  4   force =     0.01684128    0.06271162   -0.16881369
     atom   40 type  4   force =     0.01684137    0.06271191   -0.16881443
     atom   41 type  4   force =     0.05926419    0.21504962   -0.01148228
     atom   42 type  4   force =     0.05926450    0.21505075   -0.01148234
     atom   43 type  4   force =     0.05926419   -0.21504962   -0.01148228
     atom   44 type  4   force =     0.05926450   -0.21505072   -0.01148234
     atom   45 type  4   force =    -0.05926419    0.21504962    0.01148228
     atom   46 type  4   force =    -0.05926450    0.21505072    0.01148234
     atom   47 type  4   force =    -0.05926419   -0.21504962    0.01148228
     atom   48 type  4   force =    -0.05926450   -0.21505075    0.01148234

     ...........

     Total force =     2.613470     Total SCF correction =     0.000031

     Total Dispersion Force =     0.007543

     ...........

     BFGS Geometry Optimization

     number of scf cycles    =   1
     number of bfgs steps    =   0

     energy   new            =   -1426.3183075352 Ry

     new trust radius        =       0.5000000000 bohr
     new conv_thr            =       0.0000001000 Ry


**** QE input file starts here ***********************************
&control
  title = 'Gypsum (CaSO4.2H20 Z=4)'
  prefix = 'gypsum-SSSP_acc_PBE-exp0.56G'
  outdir = '/work2/u2equa02/tempdir/gypsum-SSSP_acc_PBE-exp0.56G'
  pseudo_dir = '/home/u2equa02/quantumhome/pseudo'
  calculation = 'relax'
  restart_mode = 'from_scratch'
  disk_io = 'low'
  verbosity = 'high'
  tstress = .true.
  tprnfor = .true.
  nstep = 1
  etot_conv_thr = 1.0D-5
  forc_conv_thr = 1.0D-4
  iprint = 1
/
&system
  ibrav = 0
  ntyp = 4
  nat = 48
  ecutwfc = 100
  ecutrho = 800
  vdw_corr = 'grimme-d2'
/
&electrons
  electron_maxstep = 200
  conv_thr = 1.0D-7
  diago_thr_init = 1.0D-4
  startingpot = 'atomic'
  startingwfc = 'atomic+random'
  mixing_mode = 'plain'
  mixing_beta = 0.5
  mixing_ndim= 8
  diagonalization = 'david'
/
&ions
  ion_dynamics = 'bfgs'
/

ATOMIC_SPECIES
   Ca   40.0780000000  Ca_pbe_v1.uspp.F.UPF
    S   32.0650000000  S_pbe_v1.2.uspp.F.UPF
    O   15.9994000000  O.pbe-n-kjpaw_psl.0.1.UPF
    H    1.0079000000  H.pbe-rrkjus_psl.0.1.UPF

ATOMIC_POSITIONS crystal
Ca      0.00000000000000      0.17110000000000      0.25000000000000 0 0 0
Ca      0.50000000000000      0.67110000000000      0.25000000000000 0 0 0
Ca      0.00000000000000      0.82890000000000      0.75000000000000 0 0 0
Ca      0.50000000000000      0.32890000000000      0.75000000000000 0 0 0
 S      0.00000000000000      0.32880000000000      0.75000000000000 0 0 0
 S      0.50000000000000      0.82880000000000      0.75000000000000 0 0 0
 S      0.00000000000000      0.67120000000000      0.25000000000000 0 0 0
 S      0.50000000000000      0.17120000000000      0.25000000000000 0 0 0
 O      0.08200000000000      0.27600000000000      0.59100000000000 0 0 0
 O      0.58200000000000      0.77600000000000      0.59100000000000 0 0 0
 O      0.08200000000000      0.72400000000000      0.09100000000000 0 0 0
 O      0.58200000000000      0.22400000000000      0.09100000000000 0 0 0
 O      0.91800000000000      0.27600000000000      0.90900000000000 0 0 0
 O      0.41800000000000      0.77600000000000      0.90900000000000 0 0 0
 O      0.91800000000000      0.72400000000000      0.40900000000000 0 0 0
 O      0.41800000000000      0.22400000000000      0.40900000000000 0 0 0
 O      0.20300000000000      0.38700000000000      0.91700000000000 0 0 0
 O      0.70300000000000      0.88700000000000      0.91700000000000 0 0 0
 O      0.20300000000000      0.61300000000000      0.41700000000000 0 0 0
 O      0.70300000000000      0.11300000000000      0.41700000000000 0 0 0
 O      0.79700000000000      0.38700000000000      0.58300000000000 0 0 0
 O      0.29700000000000      0.88700000000000      0.58300000000000 0 0 0
 O      0.79700000000000      0.61300000000000      0.08300000000000 0 0 0
 O      0.29700000000000      0.11300000000000      0.08300000000000 0 0 0
 O      0.78700000000000      0.06900000000000      0.91800000000000 0 0 0
 O      0.28700000000000      0.56900000000000      0.91800000000000 0 0 0
 O      0.78700000000000      0.93100000000000      0.41800000000000 0 0 0
 O      0.28700000000000      0.43100000000000      0.41800000000000 0 0 0
 O      0.21300000000000      0.06900000000000      0.58200000000000 0 0 0
 O      0.71300000000000      0.56900000000000      0.58200000000000 0 0 0
 O      0.21300000000000      0.93100000000000      0.08200000000000 0 0 0
 O      0.71300000000000      0.43100000000000      0.08200000000000 0 0 0
 H      0.74200000000000      0.08700000000000      0.76600000000000 1 1 1
 H      0.24200000000000      0.58700000000000      0.76600000000000 1 1 1
 H      0.74200000000000      0.91300000000000      0.26600000000000 1 1 1
 H      0.24200000000000      0.41300000000000      0.26600000000000 1 1 1
 H      0.25800000000000      0.08700000000000      0.73400000000000 1 1 1
 H      0.75800000000000      0.58700000000000      0.73400000000000 1 1 1
 H      0.25800000000000      0.91300000000000      0.23400000000000 1 1 1
 H      0.75800000000000      0.41300000000000      0.23400000000000 1 1 1
 H      0.75600000000000      0.02000000000000      0.92300000000000 1 1 1
 H      0.25600000000000      0.52000000000000      0.92300000000000 1 1 1
 H      0.75600000000000      0.98000000000000      0.42300000000000 1 1 1
 H      0.25600000000000      0.48000000000000      0.42300000000000 1 1 1
 H      0.24400000000000      0.02000000000000      0.57700000000000 1 1 1
 H      0.74400000000000      0.52000000000000      0.57700000000000 1 1 1
 H      0.24400000000000      0.98000000000000      0.07700000000000 1 1 1
 H      0.74400000000000      0.48000000000000      0.07700000000000 1 1 1

K_POINTS automatic
12 6 18 0 0 0

CELL_PARAMETERS bohr
    11.83535471815098      0.00000000000000      0.00000000000000
     0.00000000000000     28.65391722678003      0.00000000000000
    -4.39283675093634      0.00000000000000      9.75628273508813





Tsung-Lung Li, Ph. D.
Professor
Department of Applied Physics
National Chia-Yi University
300 Hsueh-Fu Road, Chiayi 60004, Taiwan
Phone: 886-5-2717904.  FAX: 886-5-2717909.
E-mail:quantum at mail.ncyu.edu.tw    
URL:http://web.ncyu.edu.tw/~quantum




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