[Pw_forum] convergence problem of FePc molecule

[琨陶]

Dear all,

I just start to learn Quantum Espresso, and want to optimize the geometry
of an FePc molecule. But, it doesn't converge even after 500 steps. Could
you give me some suggestions? Any suggestions are welcome!

Regards,
Kun Tao


Attached below is the input file:

&CONTROL
    calculation = 'scf'
    restart_mode='from_scratch',
    prefix='FePc',
    pseudo_dir = './',
    outdir='./temp'
    etot_conv_thr=1.D-4
    forc_conv_thr=1.D-2
 /
 &SYSTEM
   ibrav=6,
   celldm(1)=41.58,
   celldm(3)=0.454545,
   nat=  57,
   ntyp= 4,
   ecutwfc = 27.0,
   ecutrho = 250.0,
  & occupations='fixed',
   smearing='marzari-vanderbilt',
   degauss=0.1,
   nspin=2,
   assume_isolated = 'martyna-tuckerman'
   starting_magnetization(1)= 1,
  & lda_plus_u = .true.
  & Hubbard_U(1)= 1.d-20
  & Hubbard_U(2)= 1.d-20
  & nbnd = 380
 /
 &ELECTRONS
   diagonalization='cg',
   conv_thr    = 1.D-4,
   mixing_beta = 0.05D0,
   electron_maxstep = 500,
 /
&IONS
  & ion_dynamics = 'bfgs'
   bfgs_ndim = 3
/
ATOMIC_SPECIES
  C  12.0  C.pw91-van_ak.UPF
  H  1.0  H.pw91-van_ak.UPF
  N  14.0  N.pw91-van_ak.UPF
  Fe 55.8  Fe.pw91-sp-van_ak.UPF
ATOMIC_POSITIONS {Angstrom}
 C   12.15539372    13.73909330    5.04996061
 C   13.73649156    12.16178989    5.05578041
 C   13.43098617    14.43384445    5.05163491
 C   14.42783630    13.43936718    5.06136000
 C   13.76218534    15.79065418    5.04836023
 C   15.78316009    13.77488291    5.07699788
 C   13.73909330    9.84460628    5.04996061
 C   12.16178989    8.26350933    5.05578041
 C   14.43384445    8.56901383    5.05163491
 C   13.43936718    7.57216460    5.06136000
 C   15.79065418    8.23781467    5.04836023
 C   13.77488291    6.21683902    5.07699788
 C   9.84460628    8.26090580    5.04996061
 C   8.26350933    9.83821011    5.05578041
 C   8.56901383    7.56615555    5.05163491
 C   7.57216460    8.56063193    5.06136000
 C   8.23781467    6.20934671    5.04836023
 C   6.21683902    8.22511798    5.07699788
 C   8.26090580    12.15539372    5.04996061
 C   9.83821011    13.73649156    5.05578041
 C   7.56615555    13.43098617    5.05163491
 C   8.56063193    14.42783630    5.06136000
 C   6.20934671    13.76218534    5.04836023
 C   8.22511798    15.78316009    5.07699788
 C   6.87043524    16.11305392    5.07808685
 C   5.87526149    15.11545813    5.06072640
 C   5.88694608    6.87043524    5.07808685
 C   6.88454098    5.87526149    5.06072640
 C   15.11545813    16.12473762    5.06072640
 C   16.11305392    15.12956476    5.07808685
 C   16.12473762    6.88454098    5.06072640
 C   15.12956476    5.88694608    5.07808685
 H   12.98551416    16.55329919    5.03687501
 H   16.54878414    13.00105667    5.08993745
 H   16.55329919    9.01448494    5.03687501
 H   13.00105667    5.45121586    5.08993745
 H   9.01448494    5.44669992    5.03687501
 H   5.45121586    8.99894244    5.08993745
 H   5.44669992    12.98551416    5.03687501
 H   8.99894244    16.54878414    5.08993745
 H   6.57077259    17.16044581    5.09259462
 H   4.82672697    15.41213369    5.05869567
 H   4.83955419    6.57077259    5.09259462
 H   6.58786541    4.82672697    5.05869567
 H   15.41213369    17.17327213    5.05869567
 H   17.16044581    15.42922831    5.09259462
 H   17.17327213    6.58786541    5.05869567
 H   15.42922831    4.83955419    5.09259462
 N   12.36901915    9.63413960    5.05092382
 N   9.63413960    9.63097996    5.05092382
 N   9.63097996    12.36585951    5.05092382
 N   14.37677419    11.00406444    5.05336285
 N   11.00406444    7.62322491    5.05336285
 N   7.62322491    10.99593645    5.05336285
 N   10.99593645    14.37677419    5.05336285
 N   12.36585951    12.36901915    5.05092382
 Fe   11.00000000    11.00000000    5.04961908
K_POINTS Gamma
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