[Pw_forum] Calculation stops with no error message

[Dae Kwang Jun]

Dear all,

I am trying to run calculations of a ZnO SiO2 superlattices. I first tried
running a scf calculation with 4 processors. However, the calculation
didn't manage to converge even after 100 iterations. I later changed
degauss, ecutwfc, and k points to see whether this would help.
The highest degauss that I tried is 0.04, the highest ecutwfc is 80.0, and
k points is 8 8 4 0 0 0.
But doing so caused another problem. The iterations didn't start. The
output file stops writing after this:

starting charge ..., renormalized to ...
Starting wfc are .... randomized atomic wfcs

I thought that the program was taking long to start the iterations. But the
calculation gets killed after 3 or 10 hours. There is no error statement in
the .out file. Nor a CRASH file is created.

I thought that maybe I needed to correct the geometry. I tried using
vc-relax. But the same thing happens with the vc-relax calculation.

I can compute successfully bulk ZnO and SiO2 using mpirun. So I do not
think that there is a problem with the compiler or libraries.

 An example of the input file that I tried is this



&CONTROL
calculation = 'vc-relax'
...
wf_collect = .FALSE.
tstress = .FALSE.
tprnfor = .TRUE.
...
/
&SYSTEM
ibrav = 4
a = 4.91
b = 4.91
c = 42.4
nat = 69
ntyp = 3
ecutwfc = 80.0
occupations = 'smearing'
rhombohedral = .FALSE.
degauss = 0.04
/
&ELECTRONS
diagonalization = 'cg'
mixing_beta = 0.8
/
&IONS
ion_dynamics = 'bfgs'
/
&CELL
cell_dynamics = 'bfgs'
ATOMIC_SPECIES
Zn     65.38    Zn.pw-mt_fhi.UPF
O      15.99    O.pw-mt_fhi.UPF
Si      28.08    Si.pw-mt_fhi.UPF
ATOMIC_POSITIONS {angstrom}
....
K_POINTS {automatic}
8 8 4 0 0 0

In this superlattice I kept the SiO2 (ICSD ID 6205) the same. I only
changed the ZnO (ICSD ID 10137) lattice constants a and b to match the a
and b lattice constants of SiO2. I stacked them on the 001 direction.
I tried different directions and different superlattices with similar
conditions, but the calculations keep stopping with no error message. What
can I do to? What am I doing wrong?

Sincerely,

Dae Kwang Jun
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