[Pw_forum] relaxation in the presence of external electric field

[alan chen]

Dear PWSCF users,
       I turn on the 'tefield' option to relax an isolated slab system in
the presence of external electric field. The input file is attached below. I
use 'bfgs' for the ionic dynamics. However I always got the following error:
'bfgs history already reset at previous step'. Why 'bfgs' method does not
work for this 'sawlike' electric field? Shall I change some parameters?
      Thank you very much.

Hanghui Chen
Department of Physics,
Yale University

&CONTROL
  calculation='relax'
  wf_collect=.true.
  pseudo_dir = './psp'
  outdir='/home1/hc336/scratch'
  wfcdir='/home1/hc336/scratch'
  prefix='STO-efield-r-E0.01'
  tprnfor = .true.
  tstress = .true.
  disk_io='low'
  verbosity='high'
  dt=80.D0
  tefield=.true.
/
&SYSTEM
  ibrav=  6
  celldm(1) = 7.02
  celldm(3) = 5.0
  nat=  8
  ntyp= 3
  ecutwfc = 30.0
  ecutrho = 180.0
  occupations='smearing'
  smearing=gauss
  degauss=0.005
  edir=3
  emaxpos=0.8
  eopreg=0.2
  eamp=0.01
/
&ELECTRONS
  diagonalization='david'
  mixing_beta = 0.7D0
  diago_david_ndim = 4
  startingwfc='atomic'
  startingpot='atomic'
  conv_thr = 1.0d-8
/
&IONS
  ion_dynamics = 'bfgs'
  phase_space = 'full'
  pot_extrapolation = 'second_order'
  wfc_extrapolation = 'second_order'
/
&CELL
  cell_dynamics = 'damp-w'
/
ATOMIC_SPECIES
 Sr  87.62   038-Sr-ca-sp-vgrp.uspp.format.UPF
 Ti  47.90   022-Ti-ca-sp-vgrp.uspp.format.UPF
 O   16.00   008-O-ca--vgrp.uspp.format.UPF
ATOMIC_POSITIONS alat
 Ti 0.50 0.50 0.50
 O  0.00 0.50 0.50
 O  0.50 0.00 0.50
 Sr 0.00 0.00 1.00
 O  0.50 0.50 1.00
 Ti 0.50 0.50 1.50
 O  0.00 0.50 1.50
 O  0.50 0.00 1.50
K_POINTS {automatic}
10 10 1 0 0 0
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.democritos.it/pipermail/pw_forum/attachments/20080930/cf47a22a/attachment.htm