Re: [Wien] What's the difference between the spin-polarized and the non spin-polarized calculations

[Gavin Abo]

You likely have to derive the Kohm–Sham equations and solve them for the 
wavefunction solutions (and look into the WIEN2k source code) for the 
detailed answers to your questions.  I haven't done it myself, so I 
cannot help you there. I think the go to references for that were:


Planewaves, Pseudopotentials and the LAPW Method by David J. Singh and 
Lars Nordström [ 
http://link.springer.com/book/10.1007%2F978-0-387-29684-5 ]

http://www.wien2k.at/reg_user/textbooks/double_counting.pdf
http://www.wien2k.at/reg_user/textbooks/DFT_and_LAPW_2nd.pdf

My attempt at general answers:

No parameters are monitored to make the 2 densities equal.  As seen on 
slide 21 of http://www.wien2k.at/events/ws2015/rolask_rela.pdf , there 
are two equations, one for Psi_up and one for Psi_down, but for the 
non-spin polarized case both equations are the same such that Psi_up = 
Psi_down = Psi.  So only one equation for the wavefunction Psi needs to 
be solved for.  As seen on slide 66 in 
http://www.wien2k.at/events/ws2015/WS22-KS-DFT-LAPW.pdf , the 
calculation is given an initial charge density (during init_lapw), then 
the charge (and spin) density should be computed from the self 
consistent field (scf) cycles (run_lapw).


On the other hand, the spin-polarized calculation (runsp_lapw) has to 
solve two separate equations instead of one as shown on slide 24 in 
rolask_rela.pdf. Which is why for example there is lapw1 -up and lapw1 
-dn for the spin-polarized calculation and only just lapw1 for the 
non-spin polarized.  The simplified equations it uses for the 
spin-polarized case was made possible by choosing the z-axis for the 
direction of the magnetic field [ Ab Initio Study of NiO-Fe Interfaces: 
Electron States and Magnetic Configurations by L. D. Giustino, 
http://www.nano-phdschool.unimore.it/site/home/phd-students/documento102017667.html 
(page 24) ].


The Bef term is crossed out on slide 21, so there should be no exchange 
magnetic potential Bxc, since Bef = Bext + Bxc (from slide 19).  
However, whether Bef term is not there or how the Bef term is set to 0, 
I don't know and someone else might; I didn't look into the source code 
to try to determine that.


On 10/19/2016 5:18 PM, Abderrahmane Reggad wrote:


Thank you Dr Gavin for your reply and also for your interesting for my 
questions.


I have checked the 2 presentations but I didn't find what I look for .

It's mentionned that in non spin-polarized calculation the spin-up 
density = the spin-down density . Which parameters are they monitored 
to make these 2 densities equal. I have read that in this case the 
exchange magnetic potential will be equal to zero. I want to know if 
it's so or not .


Best regards
--
Mr: A.Reggad
Laboratoire de Génie Physique
Université Ibn Khaldoun - Tiaret
Algerie
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Re: [Wien] What's the difference between the spin-polarized and the non spin-polarized calculations

[Abderrahmane Reggad]

Thank you Dr Gavin for your reply and also for your interesting for my
questions.

I have checked the 2 presentations but I didn't find what I look for .

It's mentionned that in non spin-polarized calculation the spin-up density
= the spin-down density . Which parameters are they monitored to make these
2 densities equal. I have read that in this case the exchange magnetic
potential will be equal to zero. I want to know if it's so or not .

Best regards
-- 
Mr: A.Reggad
Laboratoire de Génie Physique
Université Ibn Khaldoun - Tiaret
Algerie
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Re: [Wien] OK: Change of structure symmetry

[delamora]

There is a Hokey player Tomas Kana! Also from your country []

https://en.wikipedia.org/wiki/Tom%C3%A1%C5%A1_K%C3%A1%C5%88a

Tomáš Káňa - Wikipedia, the free 
encyclopedia
en.wikipedia.org
Playing career. Káňa, a center, played two seasons in the Czech Extraliga with 
HC Vítkovice before being drafted 31st overall by the St. Louis Blues in the 
2006 ...




De: Wien  en nombre de Tomas Kana 

Enviado: miércoles, 19 de octubre de 2016 06:49:34 a. m.
Para: A Mailing list for WIEN2k users
Asunto: [Wien] OK: Change of structure symmetry


Dear Pablo,

Thank you for explaining your point. Now I understand.

With best regards

Tomas

PS: No, I am not a hockey player :o)



Dear Tomas

Are you a hokey player? I suppose not!

The problem with this is that the cell goes from CXY to P then in the cell the 
number of atoms doubles.

What I did is to see the positions of the changes of the atoms with sgroup

Before sgroup:

 1: X=0.5000 Y=0. Z=0.6300
 2: X=0. Y=0. Z=0.6300
 3: X=0.5000 Y=0.2500 Z=0.38122315
 3: X=0.5000 Y=0.7500 Z=0.38122315
 4: X=0.5000 Y=0.2500 Z=0.87877685
 4: X=0.5000 Y=0.7500 Z=0.87877685
 5: X=0.7500 Y=0. Z=0.35739347
 5: X=0.2500 Y=0. Z=0.35739347

16: X=0.5000 Y=0.7500 Z=0.73290499
17: X=0.2500 Y=0.34304549 Z=0.35413297
17: X=0.7500 Y=0.65695451 Z=0.35413297
17: X=0.7500 Y=0.34304549 Z=0.35413297
17: X=0.2500 Y=0.65695451 Z=0.35413297
18: X=0.7500 Y=0.15695450 Z=0.90586703
=

After sgroup

 1: X=0.6300 Y=0.6300 Z=0.5000
 2: X=0.6300 Y=0.6300 Z=0.
 3: X=0.63122315 Y=0.38122315 Z=0.
 4: X=0.63122315 Y=0.38122315 Z=0.5000
 5: X=0.12877685 Y=0.87877685 Z=0.
 6: X=0.12877685 Y=0.87877685 Z=0.5000
 7: X=0.35739347 Y=0.35739347 Z=0.2500
 7:X= 0.35739347 Y=0.35739347 Z=0.7500
.
20: X=0.98290499 Y=0.73290499 Z=0.5000
21: X=0.51108748 Y=0.35413297 Z=0.2500
21:X= 0.51108748 Y=0.35413297 Z=0.7500
22: X=0.69717846 Y=0.35413297 Z=0.2500
22:X= 0.69717846 Y=0.35413297 Z=0.7500
23: X=0.74891253 Y=0.90586703 Z=0.2500


As you can see

a=>c

b+c=>a

c=>b

then you can see how the atoms split, for example

atoms '3' split into '3' and '4'

atoms '17' split into '21' and '22'

one have to take into account that the original structure is

CXY and a,b are equivalent to a+.5,b+.5


The b+c=>a is the consequence of the 90 => 135 degrees


I would be easy to make a program to change 135 => 90


Thank for your comments


 Pablo


De: Wien  en nombre de Tomas Kana 

Enviado: viernes, 14 de octubre de 2016 05:24:55 a. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Change of structure symmetry

Dear Pablo,
I tried to play with your structure and I succeeded.
First,  run
x supercell
always one cell in x- y- and z- directions
zero shift in all directions
 Enter your  target lattice type:
P
(you must choose primitive lattice in order to break
the symmetries you do not want there).
Zero vacuum in all directions.
Then
cp TiO2-sup_super.struct TiO2-sup.struct
Edit the TiO2-sup.struct file and find the two Cu atoms.
Rewrite the space after first Cu to 1.
Rewrite the space after second Cu to 2.
Or do these two things comfortably using w2web.
You must have them inequivalent.
By the way, are you sure that the vacuum you have for your slab is
sufficient? When I use slabs I try to have vacuum around 20 bohrs.
Then  run
x sgroup
By checking TiO2-sup.outputsgroup you see that sgroup has chosen
monoclinic lattice but with all three angles equal to 90 degrees.
(Space group 56  6 Pm)
Then, I STRONGLY RECOMMEND TO ERASE ONE OF THE Cu ATOMS,
probably the one at the position 0 0 0.
It worked on my computer.
HTH
Tomas
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Re: [Wien] Parallel LAPW1 Error

[Laurence Marks]

No attachment, so nobody can help.

On Tue, Oct 18, 2016 at 8:51 PM, Paresh Chandra Rout <
pareshchan...@iiserb.ac.in> wrote:

> Dear wien2k users and developers,
>
> I am facing an LAPW1 error while doing single point calculation. While
> initialize my calculation interactively I encounter with small G-max
> warning so  I increased it to higher value. As the lapw1 crashed again and
> again at the very first step so I  initialize the calculation  by
> constructing the case.struct file using GUI but faced the same error. I
> have attached error files and case.struct files below. Any suggestions
> regarding the above mentioned error would be highly appreciated.
>
>
>
> Kind Regards,
> Paresh Chandra Rout
> Graduate student
> Indian Institute of Science Education and Research Bhopal
>



-- 
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
www.numis.northwestern.edu ; Corrosion in 4D: MURI4D.numis.northwestern.edu
Partner of the CFW 100% program for gender equity, www.cfw.org/100-percent
Co-Editor, Acta Cryst A
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[Wien] OK: Change of structure symmetry

[Tomas Kana]

Dear Pablo,

Thank you for explaining your point. Now I understand. 


With best regards 

Tomas 

PS: No, I am not a hockey player :o)




"


Dear Tomas

Are you a hokey player? I suppose not!


The problem with this is that the cell goes from CXY to P then in the cell 
the number of atoms doubles.

What I did is to see the positions of the changes of the atoms with sgroup

Before sgroup:

 1: X=0.5000 Y=0. Z=0.6300
 2: X=0. Y=0. Z=0.6300
 3: X=0.5000 Y=0.2500 Z=0.38122315
 3: X=0.5000 Y=0.7500 Z=0.38122315
 4: X=0.5000 Y=0.2500 Z=0.87877685
 4: X=0.5000 Y=0.7500 Z=0.87877685
 5: X=0.7500 Y=0. Z=0.35739347
 5: X=0.2500 Y=0. Z=0.35739347

 
16: X=0.5000 Y=0.7500 Z=0.73290499
17: X=0.2500 Y=0.34304549 Z=0.35413297
17: X=0.7500 Y=0.65695451 Z=0.35413297
17: X=0.7500 Y=0.34304549 Z=0.35413297
17: X=0.2500 Y=0.65695451 Z=0.35413297
18: X=0.7500 Y=0.15695450 Z=0.90586703

= 
After sgroup

 1: X=0.6300 Y=0.6300 Z=0.5000
 2: X=0.6300 Y=0.6300 Z=0.
 3: X=0.63122315 Y=0.38122315 Z=0.
 4: X=0.63122315 Y=0.38122315 Z=0.5000
 5: X=0.12877685 Y=0.87877685 Z=0.
 6: X=0.12877685 Y=0.87877685 Z=0.5000
 7: X=0.35739347 Y=0.35739347 Z=0.2500
 7:X= 0.35739347 Y=0.35739347 Z=0.7500

. 
20: X=0.98290499 Y=0.73290499 Z=0.5000
21: X=0.51108748 Y=0.35413297 Z=0.2500
21:X= 0.51108748 Y=0.35413297 Z=0.7500
22: X=0.69717846 Y=0.35413297 Z=0.2500
22:X= 0.69717846 Y=0.35413297 Z=0.7500
23: X=0.74891253 Y=0.90586703 Z=0.2500

 
As you can see

a=>c

b+c=>a

c=>b

then you can see how the atoms split, for example 


atoms '3' split into '3' and '4'


atoms '17' split into '21' and '22'

one have to take into account that the original structure is 


CXY and a,b are equivalent to a+.5,b+.5




The b+c=>a is the consequence of the 90 => 135 degrees




I would be easy to make a program to change 135 => 90




Thank for your comments




 Pablo




De: Wien  en nombre de Tomas Kana <
k...@seznam.cz>
Enviado: viernes, 14 de octubre de 2016 05:24:55 a. m.
Para: A Mailing list for WIEN2k users
Asunto: Re: [Wien] Change of structure symmetry 
 
 

Dear Pablo, 
I tried to play with your structure and I succeeded. 
First,  run 
x supercell 
always one cell in x- y- and z- directions 
zero shift in all directions 
 Enter your  target lattice type:
P 
(you must choose primitive lattice in order to break 
the symmetries you do not want there). 
Zero vacuum in all directions. 
Then 
cp TiO2-sup_super.struct TiO2-sup.struct 
Edit the TiO2-sup.struct file and find the two Cu atoms. 
Rewrite the space after first Cu to 1. 
Rewrite the space after second Cu to 2. 
Or do these two things comfortably using w2web. 
You must have them inequivalent. 
By the way, are you sure that the vacuum you have for your slab is 
sufficient? When I use slabs I try to have vacuum around 20 bohrs. 
Then  run 
x sgroup 
By checking TiO2-sup.outputsgroup you see that sgroup has chosen 
monoclinic lattice but with all three angles equal to 90 degrees. 
(Space group 56  6 Pm) 
Then, I STRONGLY RECOMMEND TO ERASE ONE OF THE Cu ATOMS, 
probably the one at the position 0 0 0. 
It worked on my computer. 
HTH 
Tomas 


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Re: [Wien] About the Ueff in the the SIC approximation

[Peter Blaha]

No, there are no such checks.

On the other hand, some authors (not me) speculate about "negative U" ...

Am 19.10.2016 um 09:37 schrieb Fecher, Gerhard:

Dear Peter
Should npt be there also some restictions on U and J by some sum rules ?
 I guess -- for a rough example -- that Ueff = U-J >0 should be positive, 
otherwise the electrons may attract each other by the Coulomb interaction ??

I did not check the code, therefore the question is whether or not the program 
detects violations of sum rules that might lead to unphysical things ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Peter Blaha 
[pbl...@theochem.tuwien.ac.at]
Gesendet: Dienstag, 18. Oktober 2016 18:57
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] About the Ueff in the the SIC approximation

Of course one can use U and J, instead of an U_eff ~ U-J.
But then you have 2 parameters 

Please restrict J to physical meaningful values (~ 1 eV).

Am 18.10.2016 um 18:03 schrieb Hemza Kouarta:

Hi,

I m working on some correlated system based on iron, and I m varying the
U with the SIC approximation.

As I see the J is taken always 0,and Ueff equal to the U we take, but in
the first test I did : if we take the same U with different J ,the
results will be different (especially the magnetic moment and the
orbital moment). Did that mean that the code read the J in some subroutines.

Note:I didn't change any thing in the calculation,just the J,all the
others (kpionts,rkmax) are the same.


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--
--
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Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at
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--
--
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at
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Re: [Wien] About the Ueff in the the SIC approximation

[Fecher, Gerhard]

Dear Peter
Should npt be there also some restictions on U and J by some sum rules ?
 I guess -- for a rough example -- that Ueff = U-J >0 should be positive, 
otherwise the electrons may attract each other by the Coulomb interaction ??

I did not check the code, therefore the question is whether or not the program 
detects violations of sum rules that might lead to unphysical things ?

Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."


Dr. Gerhard H. Fecher
Institut of Inorganic and Analytical Chemistry
Johannes Gutenberg - University
55099 Mainz
and
Max Planck Institute for Chemical Physics of Solids
01187 Dresden

Von: Wien [wien-boun...@zeus.theochem.tuwien.ac.at] im Auftrag von Peter Blaha 
[pbl...@theochem.tuwien.ac.at]
Gesendet: Dienstag, 18. Oktober 2016 18:57
An: A Mailing list for WIEN2k users
Betreff: Re: [Wien] About the Ueff in the the SIC approximation

Of course one can use U and J, instead of an U_eff ~ U-J.
But then you have 2 parameters 

Please restrict J to physical meaningful values (~ 1 eV).

Am 18.10.2016 um 18:03 schrieb Hemza Kouarta:
> Hi,
>
> I m working on some correlated system based on iron, and I m varying the
> U with the SIC approximation.
>
> As I see the J is taken always 0,and Ueff equal to the U we take, but in
> the first test I did : if we take the same U with different J ,the
> results will be different (especially the magnetic moment and the
> orbital moment). Did that mean that the code read the J in some subroutines.
>
> Note:I didn't change any thing in the calculation,just the J,all the
> others (kpionts,rkmax) are the same.
>
>
> ___
> Wien mailing list
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> SEARCH the MAILING-LIST at:  
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>

--
--
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Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: bl...@theochem.tuwien.ac.atWIEN2k: http://www.wien2k.at
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