[Pw_forum] Convergence of relax of slab calculation
ben liew
liewkienben at gmail.com
Fri Aug 7 02:34:51 CEST 2015
Dear Ari Paavo Seitsonen,
Thanks for your advice. I will try your suggestion and see what will happen.
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
On Fri, Aug 7, 2015 at 1:28 AM, Mahya Zare <mahyazare68 at gmail.com> wrote:
> I want electronic and optical properties of cerium oxide do I check my
> inputs to check the correct sheet is Nano?
>
> On Thu, Aug 6, 2015 at 7:17 PM, Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>
> wrote:
>
>>
>> Dear Ben Liew,
>>
>> If one is lucky, the system might converge to the right magnetic ground
>> state with a "random guess". Yet if the system has several local minima, or
>> the initial guess is very far from the true magnetic ordering, one might
>> get very bad initial densities (total and spin density, or spin-up and
>> spin-down densities), leading to difficulties in convergence and maybe even
>> divergence. Yet-another-issue might be bad description of the electronic
>> structure with the GGA's, I seem to remember that in the case of MnO2 the
>> GGA gives reasonable results, even if the electronic band gap is naturally
>> much too small (and using the smearing should help to get a convergence
>> anyway).
>>
>> I would myself start by trying a weakly ferromagnetic guess (for
>> example 'starting_magnetization(1) = 0.2' and seeing if something happens.
>> If it converges, or doesn't, I would then see if an anti-ferromagnetic
>> solution might also make sense (two types of Mn atoms in cell, etc).
>>
>>
>> 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 Bahadir,
>>> Thanks for your comments. I will try using a lower mixing_beta and change
>>> the mixing_mode='local-TF'.
>>>
>>> Dear Ari Paavo Seitsonen,
>>>
>>> Thanks. I have no knowledge on the magnetism of my system. How could I
>>> know
>>> what value of starting_magnetization that I should use in my slab
>>> calculation? Does the starting_magnetization affect the convergence of my
>>> calculation?
>>>
>>> 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
>>>
>>> On Wed, Aug 5, 2015 at 5:20 PM, Bahadır salmankurt <
>>> bsalmankurt at gmail.com>
>>> wrote:
>>> 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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>>>
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