[Pw_forum] Convergence of relax of slab calculation

Bahadır salmankurt bsalmankurt at gmail.com
Wed Aug 5 10:20:06 CEST 2015


Dear Ari P Seitsonen,

I didnt know that mixing_mode='local-TF' effect initial magnetic moments.
thanks for this. By the way, Do you know about e field configuration? for
example, for slab + molecule systems whose atomic positions are in 0.5 and
0.65 along z direction , respectively, what must values of the
emaxpos and eopreg
be?

Bests
Bahadir

2015-08-05 10:59 GMT+03:00 Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>:

>
> Dear Ben Liew,
>
>   Without looking at the structure itself, adding to the previous comment
> about the algorithm for mixing, you have not really given any initial
> magnetic moments even if you have 'nspin = 2': The
> 'starting_magnetization(1) = 0.0' does not give any preferential spin
> ordering. Do you know something about this, is the system expected to be
> ferromagnetic, antiferromagnetic, ...?
>
>   Tiny issues, I usually do the first calculation without the surface
> dipole as it makes the convergence always a bit trickier; and your
> 'B ~= 2 * A', but you give the same number of k points in both directions.
> (I usually tend to use smearing schemes where the occupations are
> guaranteed to be in the physical range of [0:1], but this is just a
> personal preference and should thus be ignored)
>
>     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 Wed, 5 Aug 2015, ben liew wrote:
>
> Dear PWSCF users,
>>
>> Hi, I am a new user of Pwscf. I am working on slab calculation for
>> pyrolusite MnO2 (110) surface with 3 atomic layers calculation and fixed
>> bottom 2 layers and only top atomic
>> layer is allowed to be relaxed. I have also include the dipole correction
>> for the calculation to counteract with the interaction between slabs.
>> However, my calculation doesn't
>> seems to be converged as the scf accuracy is not decreasing over each
>> iteration. Below is the estimated scf accuracy after hundreds of
>> iterations, it is not converging
>>
>>      estimated scf accuracy    <     373.64728976 Ry
>>      estimated scf accuracy    <     106.52177156 Ry
>>      estimated scf accuracy    <      96.97567125 Ry
>>      estimated scf accuracy    <     207.03807187 Ry
>>      estimated scf accuracy    <     132.53045831 Ry
>>      estimated scf accuracy    <      77.19101827 Ry
>>      estimated scf accuracy    <     112.41885075 Ry
>>      estimated scf accuracy    <      93.27430429 Ry
>>      estimated scf accuracy    <     116.68049786 Ry
>>      estimated scf accuracy    <     587.09711027 Ry
>>      estimated scf accuracy    <     374.45312501 Ry
>>      estimated scf accuracy    <     106.89811469 Ry
>>      estimated scf accuracy    <      96.84898888 Ry
>>      estimated scf accuracy    <     207.83006869 Ry
>>      estimated scf accuracy    <     132.74588293 Ry
>>      estimated scf accuracy    <      77.09445200 Ry
>>      estimated scf accuracy    <     112.41688597 Ry
>>      estimated scf accuracy    <      93.57796273 Ry
>>      estimated scf accuracy    <     116.25663912 Ry
>>      estimated scf accuracy    <     587.39968959 Ry
>>      estimated scf accuracy    <     374.91438307 Ry
>>      estimated scf accuracy    <     106.71641516 Ry
>>      estimated scf accuracy    <      96.75392736 Ry
>>
>> I have include my input file as followed. Can anyone tell me is that any
>> problem with my input file?
>>
>>  &control
>>     calculation = 'relax'
>>     tstress=.true.
>>     tprnfor=.true.
>>     pseudo_dir='/home/ben/Downloads/espresso-5.1.2/pseudo'
>>     outdir='./vc3'
>>     prefix='pyrolusite'
>>     tefield=.true.
>>     dipfield=.true.
>>  /
>>  &system
>>     ibrav=8,
>>     A=2.8563, B=6.2199, C=20.0
>>     nat=18, ntyp=2,
>>     starting_magnetization(1)=0.0
>>     nspin=2
>>     ecutwfc=37.0
>>     ecutrho=250.0
>>     occupations='smearing'
>>     smearing='m-v'
>>     degauss=0.01
>>     edir=3
>>     emaxpos=0.5
>>     eopreg=0.1
>>     eamp=0.001
>>  /
>>  &electrons
>>     electron_maxstep=500
>>     conv_thr=1.0d-6
>>     mixing_beta=0.7
>>  /
>>  &ions
>>     ion_dynamics='bfgs'
>> /
>> ATOMIC_SPECIES
>>   Mn 54.9380  Mn.pbe-spn-kjpaw_psl.0.3.1.UPF
>>   O  15.9994  O.pbe-kjpaw.UPF
>> ATOMIC_POSITIONS (angstrom)
>> O         1.428129   3.109734   0.000000  0  0  0
>> O         1.428129   0.000241   0.652526  0  0  0
>> Mn       1.428129   3.109896   1.883398  0  0  0
>> O         0.000000   1.885646   1.883398  0  0  0
>> O         0.000000   4.334118   1.883398  0  0  0
>> Mn       0.000000   0.000062   1.883398  0  0  0
>> O         0.000000   5.014614   4.987475  0  0  0
>> O         0.000000   1.205401   4.987475  0  0  0
>> Mn       0.000000   3.109816   4.987475  0  0  0
>> Mn       1.428129   0.000027   4.987475  0  0  0
>> O         1.428129   3.109734   3.767387  0  0  0
>> O         1.428129   0.000241   3.114269  0  0  0
>> O         1.428129   3.109734   6.207560
>> O         1.428129   0.000241   6.860698
>> Mn       1.428129   3.109896   8.091569
>> O         0.000000   1.885646   8.091569
>> O         0.000000   4.334118   8.091569
>> Mn       0.000000   0.000062   8.091569
>> K_POINTS (automatic)
>>   5 5 1 0 0 0
>>
>> Your comments and suggestion is much appreciated.Thank you.
>>
>>
>> Best Regards,
>> Ben Liew
>> Ph.D Student
>> Fuel Cell Institute,
>> The National University of Malaysia,
>> 43600 Bangi,
>> Selangor, Malaysia.
>> Contact no. : +6016 552 0878
>> Email           : liewkienben at gmail.com
>>
>>
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