[Pw_forum] convergence NOT achieved after 100 iterations: stopping (even for a relaxed structure from VASP)

Ari P Seitsonen Ari.P.Seitsonen at iki.fi
Thu Oct 8 11:32:16 CEST 2015


Dear Masood Yousaf,

   Sorry, my mistake indeed: I forgot that XCrysDen (at least in version 
1.5.53) does not recognise the Ångström units. Please try with 'local-TF'.

     Greetings,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
   Ecole Normale Supérieure (ENS), Département de Chimie, Paris
   Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935


On Thu, 8 Oct 2015, Masood Yousaf wrote:

> Dear A. P. Seitsonen,
> 
> thank you for your suggestions. I will try it. Would you please explain more
> about your comment "Please try multiplying your lattice vectors laterally by
> two". What is motivation behind this move ? The input lattice vectors are in
> accordance with the 2*2 supercell.
> 
> Best wishes
> Masood Yousaf
> UNIST, KOREA  
> 
> 
> 
> On Thu, Oct 8, 2015 at 5:30 PM, Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>
> wrote:
>
>       Dear Masood Yousaf,
>
>         Please try multiplying your lattice vectors laterally by two;
>       I would also try the 'mixing_mode = "local-TF"': That works
>       better for me in inhomogeneous systems such as slabs (ie where
>       there are high-density regions and vacuum).
>
>         Some other notes:
>
>        - Why not using 'ibrav = 4' and 'a', 'c' to define the lattice
>       vectors? You would have much better accuracy, symmetries etc.
>       Likewise for the coordinates, more precise digits would allow
>       finding symmetries etc
>
>        - Eventually the FHI potentials will need much higher cut-off
>       energy, I seem to remember something like 90-120 Ry for Ni...
>       (just for curiosity, I had the honour to share the office for
>       some time with the GPP, Guru of Pseudo Potentials, at FHI, from
>       whom the parametres of these pseudos might still originate from
>       ;)
>
>           Good Luck from Almost-Sunny Montrouge,
>
>              apsi
> 
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*
>       =-
>         Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi /
>       http://www.iki.fi/~apsi/
>         Ecole Normale Supérieure (ENS), Département de Chimie, Paris
>         Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935
> 
>
>       On Thu, 8 Oct 2015, Masood Yousaf wrote:
>
>             Dear Members,
>
>             Kindly have a look at the input file and suggest 
>             why its so hard to
>             converge this relatively moderate system. I tried to
>             fix in different ways
>             but failed. I tried the same structure in VASP and
>             had no problem. I want to
>             calculate RAMMAN spectra and that can only be
>             calculated with LDA functional
>             in Quantum espresso. I am using QE 5.1.
> 
>
>              &control
>                 calculation='relax'
>                 restart_mode='from_scratch'
>                 pseudo_dir = '/share/QE_pseudo'
>                 outdir='./'
>                 prefix='Graphane'
>                 forc_conv_thr=1.0D-4
>                 nstep=10000
>             /
>              &system
>                 ibrav=  0
>                 nat=  32,  ntyp= 3
>                 nspin =2
>                 starting_magnetization(2) = 0.7
>                 ecutwfc =60.0
>                 occupations='smearing'
>                 degauss=0.002
>                 smearing='mv',
>             /
>              &electrons
>                 conv_thr=1.0D-9
>                 mixing_mode='plain'
>                 mixing_beta=0.1D0
>              /
>             &ions
>                ion_dynamics = 'bfgs'
>               /
>             ! &cell
>             !    cell_dynamics = 'damp-w'
>             !   cell_factor = 10.1D0
>             /
>             CELL_PARAMETERS {angstrom}
>                  4.9363447999999996    0.0000000000000000   
>             0.0000000000000000
>                  2.4681723999999998    4.2750000000000004   
>             0.0000000000000000
>                  0.0000000000000000    0.0000000000000000  
>             25.0000000000000000
>             ATOMIC_SPECIES
>             C  12.0111 C.pw-mt_fhi.UPF
>             Ni 58.6934 Ni.pw-mt_fhi.UPF
>             F  18.9984  F.pw-mt_fhi.UPF
>             ATOMIC_POSITIONS {angstrom}
>             C        3.116840000      3.174350000     
>             1.386070000
>             C        5.584900000      3.174230000     
>             1.386000000
>             C        1.882610000      1.036880000     
>             1.385940000
>             C        4.350760000      1.036680000     
>             1.385960000
>             C        1.882750000      2.461910000     
>             1.888240000
>             C        0.648640000      0.324320000     
>             1.888230000
>             C        4.350960000      2.461770000     
>             1.888140000
>             C        3.116790000      0.324280000     
>             1.888150000
>             C        1.882980000      2.461940000     
>             3.476540000
>             C        0.648890000      0.324350000     
>             3.476400000
>             C        4.351250000      2.461930000     
>             3.476230000
>             C        3.117130000      0.324400000     
>             3.476380000
>             C        6.819130000      3.887150000     
>             3.951040000
>             C        4.351050000      3.887040000     
>             3.950790000
>             C        3.116960000      1.749700000     
>             3.950740000
>             C        5.585010000      1.749700000     
>             3.950910000
>             Ni       6.828000000      3.886970000     
>             5.917170000
>             Ni       3.131720000      0.323340000     
>             7.993850000
>             Ni       4.367640000      1.035220000    
>             10.009150000
>             Ni       4.359850000      3.886850000     
>             5.916790000
>             Ni       0.663590000      0.323340000     
>             7.993930000
>             Ni       1.899450000      1.035270000    
>             10.009360000
>             Ni       5.593900000      1.749490000     
>             5.916940000
>             Ni       4.365770000      2.460850000     
>             7.993890000
>             Ni       5.601750000      3.172800000    
>             10.009260000
>             Ni       3.125750000      1.749380000     
>             5.916700000
>             Ni       1.897660000      2.460880000     
>             7.993900000
>             Ni       3.133520000      3.172820000    
>             10.009440000
>             F        5.584240000      3.175000000     
>             0.000730000
>             F        4.350170000      1.037440000     
>             0.000850000
>             F        1.882110000      1.037660000     
>             0.000890000
>             F        3.116200000      3.175230000     
>             0.000920000
>             K_POINTS {automatic}
>               5 5 1 0 0 0
> 
>
>             --
>
>             Best Wishes
>
>             Masood Yousaf
>
>             Ulsan National Institute of Science and Technology,
>             Korea
> 
> 
> 
>
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> 
> 
> 
> 
> --
> 
> Best Wishes
> 
> Masood Yousaf
> 
> Postdoctoral researcher
> 
> Ulsan National Institute of Science and Technology, Korea
> 
> Cell.: +82-010-3320-1984
> 
> 
>


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