[Pw_forum] Fwd: Basic Relax Calculation issues

[Zarah Baiyee]

Hi All,

I am a new user to Quantum Espresso, therefore this may be a bit trivial
but I any help would be very welcome.

I am attempting a relax calculation using espresso version 5.0.2, for the
geometry optimisation of a perovskite structure. For the input below, the
calculation runs, however does not compute any forces and convergence
without geometry optimisation to the original structure, with 0 bfgs steps.
I am able to perform an expected relaxation if alter the initial atomic
positions to asymmetric: (i.e.)  an oxygen molecule from:  O (0.500  0.5
 0.0) to O(0.499 0.5 0.0).

Please may someone shed some light on to why this is the case, and if there
is anything wrong with my input.

Thanks

Zarah
Zbaiyee at gmail.com

&CONTROL
  calculation  = "relax",
  prefix       = "CO",
  pseudo_dir   = "/Users/zarahbaiyee/espresso-5.0.2/pseudo",
  outdir       = "/Users/zarahbaiyee/tmp",
  forc_conv_thr = 1.0D-5
/
&SYSTEM
  ibrav     = 0,
  nat       = 5,
  ntyp      = 3,
  ecutwfc   = 60,
  ecutrho   = 420,
/
&ELECTRONS
  conv_thr    = 1.D-7,
  mixing_beta = 0.7D0,
  electron_maxstep = 400
/
&IONS
/
CELL_PARAMETERS bohr
 7.60  0.0  0.0
 0.0  7.60  0.0
 0.0  0.0  7.60
ATOMIC_SPECIES
 Ba  137.32 Ba.pbe-mt_fhi.UPF
 Fe  55.84 Fe.pbe-mt_fhi.UPF
 O   15.99 O.pbe-kjpaw.UPF
ATOMIC_POSITIONS {crystal}
Ba  0.000  0.0  0.0  0 0 0
Fe  0.500  0.5  0.5
O   0.000  0.5  0.5
O   0.500  0.0  0.5
O   0.500  0.5  0.0
K_POINTS {automatic}
9 9 9 0 0 0
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140228/718a2341/attachment.html>