[Pw_forum] Difficulties with scf convergence

[Никита Вакула]

 Hi everybody,

I am trying to optimize the structure of an interface between metal and insulator but have difficulties with scf convergence. Here are the changes in energies during scf cycle:
estimated scf accuracy < 17.58555120 Ry
estimated scf accuracy < 14.17435383 Ry
estimated scf accuracy < 2.05765892 Ry
estimated scf accuracy < 2.09375911 Ry
estimated scf accuracy < 1.37675281 Ry
estimated scf accuracy < 0.42594758 Ry
estimated scf accuracy < 0.29104539 Ry
estimated scf accuracy < 0.51143695 Ry
estimated scf accuracy < 0.18765814 Ry
estimated scf accuracy < 0.92590998 Ry
estimated scf accuracy < 0.93126088 Ry
estimated scf accuracy < 0.44023978 Ry
estimated scf accuracy < 0.33756785 Ry
estimated scf accuracy < 0.34216551 Ry
estimated scf accuracy < 0.36573444 Ry
estimated scf accuracy < 0.29089342 Ry
estimated scf accuracy < 0.29287805 Ry
estimated scf accuracy < 0.16940331 Ry
estimated scf accuracy < 0.17503222 Ry
estimated scf accuracy < 0.09708451 Ry
estimated scf accuracy < 0.07751341 Ry
estimated scf accuracy < 0.06774554 Ry
estimated scf accuracy < 0.15834930 Ry
estimated scf accuracy < 0.12269823 Ry
estimated scf accuracy < 0.12679734 Ry
estimated scf accuracy < 0.08558475 Ry
estimated scf accuracy < 0.04411767 Ry
estimated scf accuracy < 0.04754042 Ry

I found similar posts on the forum  but it didn't solve the problem. I checked my structure with xcrysen...it seems to be ok. I am using USPP.
Any help and suggestions would be greatly appreciated.

Thanks

Here is my input:
&CONTROL
title = interface ,
calculation = 'relax' ,
restart_mode = 'from_scratch' ,
wf_collect = .true. ,
outdir = 'interface/' ,
pseudo_dir = './' ,
prefix = 'interface' ,
lkpoint_dir = .true. ,
disk_io = 'high' ,
verbosity = 'high' ,
nstep = 100 ,
tstress = .false. ,
tprnfor = .true. ,
/
&SYSTEM
ibrav = 8,
celldm(1) = 9.3957,
celldm(2) = 1.7321,
celldm(3) = 6.0000,
nat = 72,
ntyp = 3,
ecutwfc = 50 ,
ecutrho = 500 ,
nbnd = 500,
occupations = 'smearing' ,
degauss = 0.025 ,
smearing = 'methfessel-paxton' ,
nspin = 1 ,
/
&ELECTRONS
electron_maxstep = 200,
conv_thr = 1.0d-6 ,
mixing_mode = 'local-TF' ,
mixing_beta = 0.1 ,
mixing_ndim = 8 ,
/
&IONS
ion_dynamics = 'bfgs' ,
/
ATOMIC_SPECIES
  BR,

N V
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