[Pw_forum] problem with the geometry optimization of cp.x

[Alex]

Dear user QE.

I'm using cp.x to perform molecular dynamics of one of bulk water molecules with asparagine.
Following protocol, I minimized the function of wave electronics with stationary nuclei.

However, in the second stage, during the optimization of the geometry (with damp for electrons and ions) 
the water molecules take a non-real geometry, in which one side of the molecule, the OH distance becomes 1.98 angstrorn (A).
The opposite side, has the normal size of the bond which is 0.97 A. I confess that since I started using it very often, 
and sometimes does not, but do not know why that. Sometimes change is functional and that resolved, sometimes not.



Incoherent bond distances of water after geometry optmization  >>>>>   H------------------O -----------H
(sorry by bad graphic)                                                                                  | 1.98 A|       |0.97 A|


Can someone help me? 
Put my input to be analyzed.


&CONTROL
  title = 'Asp0s'
  calculation = 'cp',
  restart_mode = 'restart',
  ndr = 51      !already minimized wf with sd for electrons and ions=none.
  ndw = 52, 
  nstep  = 50000,
  iprint = 1, 
  isave  = 10,
  tstress = .TRUE.,
  tprnfor = .TRUE.,
  dt    = 5.0d0,
  etot_conv_thr = 1.d-8,
  ekin_conv_thr = 1.d-4,
  forc_conv_thr = 1.d-4,
  prefix = 'asp'
  pseudo_dir = 'pseudo/'
  outdir = './'
/

&SYSTEM
  ibrav = 1, 
  celldm(1) = 20, 
  celldm(2) = 0.0, 
  celldm(3) = 0.0, 
  celldm(4) = 0.0, 
  celldm(5) = 0.0, 
  celldm(6) = 0.0, 
  nat  = 122,
  ntyp = 4,
  ecutwfc = 70.0,
/

&ELECTRONS
  emass = 400.d0,
  emass_cutoff = 2.5d0,
  orthogonalization = 'ortho',
  electron_dynamics = 'damp',
  electron_damping = 0.1
  ortho_max = 500,
  !electron_temperature = 'not_controlled',
  !electron_velocities = 'zero'
/

&IONS
  ion_dynamics = 'damp',
  ion_damping = 0.01,
  !ion_nstepe = 10,
  !ion_temperature = 'nose',
  !tempw = 350,
  !fnosep = 70,
  !ion_velocities = 'zero'
/


ATOMIC_SPECIES

 O 16.0d0  O.pbe-hgh.UPF
 H 1.0d0   H.pbe-hgh.UPF 
 C 12.0d0  C.pbe-hgh.UPF 
 N 14.0d0  N.pbe-hgh.UPF

ATOMIC_POSITIONS {angstrom}

   C     -0.244144     1.783022    -1.335832 
   C     -2.567204    -0.241389     5.783803 
   N     -1.038197    -1.652589     5.418683 
   C     -6.336078    -1.532299    -1.532562 
   O     -5.122808    -0.424258    -2.279843 
   N      3.987336     0.412822    -1.692063 
   C      0.552282    -0.043486     0.368085 
   O      1.73575      0.043368     0.476670 
   O      1.126133    -1.181319     1.757325 
   H     -0.844512    -1.781630    -0.580034 
   H     -1.992345    -1.968023     0.581635 
   H     -1.547999    -0.018973     1.618910 
   H     -1.017864     1.793541     0.067225 
   H     -2.180408     0.669590    -0.675764 
   H      1.490782     1.185685    -2.387313 
   H      1.070763     1.992771    -0.909308 
   H      0.490233    -1.888235     1.458829 
   O      5.160929     1.400891    -4.018523 
   H      5.585303     1.845186    -4.767840 
   H      5.903707     1.074826    -3.488501 
   O      6.523016    -2.630620    -1.333026 
   H      6.731773    -1.730291    -1.624223 
   H      6.238875    -2.519196    -0.413345 
( ........)


Alex.
Thanks to all.
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