[Pw_forum] Not conversed force for relaxed calculation

[yukihiro_okuno at fujifilm.co.jp]

Dear PWSCF users.

I'm working to calculate the monoclinic structure of PZT
materials.
In order to get relaxed atomic positions,
I calculated the relax atomic structure but the Total force
of system is not conversed and remains like,

Total force =     0.006134     Total SCF correction =     0.000026
Total force =     0.006306     Total SCF correction =     0.000021
Total force =     0.006475     Total SCF correction =     0.000042
Total force =     0.006606     Total SCF correction =     0.000007
Total force =     0.006711     Total SCF correction =     0.000023
Total force =     0.006784     Total SCF correction =     0.000017
Total force =     0.006845     Total SCF correction =     0.000019
Total force =     0.006894     Total SCF correction =     0.000041
Total force =     0.006947     Total SCF correction =     0.000025
Total force =     0.006990     Total SCF correction =     0.000023

when such a not conversed total force has happened, how should we
treat the problem ,and where we change the input parameters.

Sincerely yours.

My input file is as follow,

 &control
    calculation  = 'relax',
    restart_mode = 'from_scratch',
    pseudo_dir   = '../../pseudo/',
    outdir       = './',
    prefix='PZT'
    forc_conv_thr = 1.0D-4
 /
 &system
    ibrav=12
    celldm(1)=7.57696068724
    celldm(2)=2.09000418
    celldm(3)=1.00
    celldm(4)= 0.00199999600001
    nat=10
    ntyp=4
    nbnd=44
    ecutwfc=60.0
    ecutrho = 600.0
    occupations = 'fixed'
    degauss=0.00
 /
 &electrons
    conv_thr = 1e-9,
    mixing_beta=0.3,
 /
&IONS
 ion_dynamics='bfgs'
 bfgs_ndim=3
 pot_extrapolation = "second_order"
 wfc_extrapolation = "second_order"
 trust_radius_max=5.0D-3
 trust_radius_min=1.0D-4
/
ATOMIC_SPECIES
  Pb  207.2     pb_ps.uspp.UPF
  Zr  91.224    zr_ps.uspp.UPF
  Ti  47.867    ti_ps.uspp.UPF
  O   15.9994   o_ps.uspp.UPF
ATOMIC_POSITIONS {crystal}
Pb       0.002397553   0.006008858   0.000000000
Pb       0.002030389   0.537841278   0.000000000
Zr       0.500010466   0.244178434   0.500000000
Ti       0.501896689   0.740659564   0.500000000
O        0.498716727   0.951077912   0.500000000
O        0.498709982   0.478318964   0.500000000
O        0.499093210   0.189008468   0.000000000
O       -0.000233773   0.189010061   0.500000000
O        0.498627112   0.711878632   0.000000000
O       -0.001248355   0.711877827   0.500000000
K_POINTS {automatic}
  6 6 6 0 0 0