[Pw_forum] convergence problem of FePc molecule

Thomas Brumme Thomas.Brumme at impmc.upmc.fr
Mon Sep 1 16:16:10 CEST 2014


Btw: I wanted to say x/y-axes not x/z...

On 09/01/2014 03:57 PM, ?? wrote:
> Dear Thomas,
>
> Thank you for your suggestions! I will try do some calculations 
> according to your suggestions.
>
> Regards,
> Kun Tao
>
>
> On 1 September 2014 15:47, Thomas Brumme <Thomas.Brumme at impmc.upmc.fr 
> <mailto:Thomas.Brumme at impmc.upmc.fr>> wrote:
>
>     Dear Kun Tao,
>
>     first of all, I would shift the molecule with the iron in the origin.
>     If you furthermore align the lobes with the x/z-axes the code will
>     find
>     at least some of the symmetries of the molecule and this will speed up
>     the calculations.
>
>     Concerning the convergence... I would first try with gaussian smearing
>     instead of marzari-vanderbilt and reduce the smearing (degauss) a
>     little
>     bit. And if your convergence threshold is 1.D-4 and it's still not
>     converging
>     something is wrong maybe with the pseudos?! Even if those are
>     ultrasoft
>     ones, a wavefunction cutoff of 27 Ry is maybe to small for Fe? But
>     maybe
>     someone else has more experience with those pseudos...
>
>     Regards
>
>     Thomas
>
>
>     On 09/01/2014 01:57 PM, ?? wrote:
>>     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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>
>     -- 
>     Dr. rer. nat. Thomas Brumme
>     Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie
>     Sorbonne Universités - UPMC Univ Paris 06
>     4 Place Jussieu
>     75005 Paris
>
>     Tel:  +33 (0) 1 442 77204
>
>     email:Thomas.Brumme at impmc.upmc.fr  <mailto:Thomas.Brumme at impmc.upmc.fr>
>
>
>     _______________________________________________
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>     http://pwscf.org/mailman/listinfo/pw_forum
>
>
>
>
> _______________________________________________
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-- 
Dr. rer. nat. Thomas Brumme
Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie
Sorbonne Universités - UPMC Univ Paris 06
4 Place Jussieu
75005 Paris

Tel:  +33 (0) 1 442 77204

email: Thomas.Brumme at impmc.upmc.fr

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