[Pw_forum] Convergence of relax of slab calculation

[ben liew]

Dear PWSCF users,

Hi, I am a new user of Pwscf. I am working on slab calculation for
pyrolusite MnO2 (110) surface with 3 atomic layers calculation and fixed
bottom 2 layers and only top atomic layer is allowed to be relaxed. I have
also include the dipole correction for the calculation to counteract with
the interaction between slabs. However, my calculation doesn't seems to be
converged as the scf accuracy is not decreasing over each iteration. Below
is the estimated scf accuracy after hundreds of iterations, it is not
converging

     estimated scf accuracy    <     373.64728976 Ry
     estimated scf accuracy    <     106.52177156 Ry
     estimated scf accuracy    <      96.97567125 Ry
     estimated scf accuracy    <     207.03807187 Ry
     estimated scf accuracy    <     132.53045831 Ry
     estimated scf accuracy    <      77.19101827 Ry
     estimated scf accuracy    <     112.41885075 Ry
     estimated scf accuracy    <      93.27430429 Ry
     estimated scf accuracy    <     116.68049786 Ry
     estimated scf accuracy    <     587.09711027 Ry
     estimated scf accuracy    <     374.45312501 Ry
     estimated scf accuracy    <     106.89811469 Ry
     estimated scf accuracy    <      96.84898888 Ry
     estimated scf accuracy    <     207.83006869 Ry
     estimated scf accuracy    <     132.74588293 Ry
     estimated scf accuracy    <      77.09445200 Ry
     estimated scf accuracy    <     112.41688597 Ry
     estimated scf accuracy    <      93.57796273 Ry
     estimated scf accuracy    <     116.25663912 Ry
     estimated scf accuracy    <     587.39968959 Ry
     estimated scf accuracy    <     374.91438307 Ry
     estimated scf accuracy    <     106.71641516 Ry
     estimated scf accuracy    <      96.75392736 Ry

I have include my input file as followed. Can anyone tell me is that any
problem with my input file?

 &control
    calculation = 'relax'
    tstress=.true.
    tprnfor=.true.
    pseudo_dir='/home/ben/Downloads/espresso-5.1.2/pseudo'
    outdir='./vc3'
    prefix='pyrolusite'
    tefield=.true.
    dipfield=.true.
 /
 &system
    ibrav=8,
    A=2.8563, B=6.2199, C=20.0
    nat=18, ntyp=2,
    starting_magnetization(1)=0.0
    nspin=2
    ecutwfc=37.0
    ecutrho=250.0
    occupations='smearing'
    smearing='m-v'
    degauss=0.01
    edir=3
    emaxpos=0.5
    eopreg=0.1
    eamp=0.001
 /
 &electrons
    electron_maxstep=500
    conv_thr=1.0d-6
    mixing_beta=0.7
 /
 &ions
    ion_dynamics='bfgs'
/
ATOMIC_SPECIES
  Mn 54.9380  Mn.pbe-spn-kjpaw_psl.0.3.1.UPF
  O  15.9994  O.pbe-kjpaw.UPF
ATOMIC_POSITIONS (angstrom)
O         1.428129   3.109734   0.000000  0  0  0
O         1.428129   0.000241   0.652526  0  0  0
Mn       1.428129   3.109896   1.883398  0  0  0
O         0.000000   1.885646   1.883398  0  0  0
O         0.000000   4.334118   1.883398  0  0  0
Mn       0.000000   0.000062   1.883398  0  0  0
O         0.000000   5.014614   4.987475  0  0  0
O         0.000000   1.205401   4.987475  0  0  0
Mn       0.000000   3.109816   4.987475  0  0  0
Mn       1.428129   0.000027   4.987475  0  0  0
O         1.428129   3.109734   3.767387  0  0  0
O         1.428129   0.000241   3.114269  0  0  0
O         1.428129   3.109734   6.207560
O         1.428129   0.000241   6.860698
Mn       1.428129   3.109896   8.091569
O         0.000000   1.885646   8.091569
O         0.000000   4.334118   8.091569
Mn       0.000000   0.000062   8.091569
K_POINTS (automatic)
  5 5 1 0 0 0

Your comments and suggestion is much appreciated.Thank you.


Best Regards,

*Ben Liew*
Ph.D Student
Fuel Cell Institute,
The National University of Malaysia,
43600 Bangi,
Selangor, Malaysia.
Contact no. : +6016 552 0878
Email           : liewkienben at gmail.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20150805/ad3d2c63/attachment.html>