Re: [Wien] How to include the localized d orbitals in the atomic spheres?

2016-11-27 Thread Fecher, Gerhard 
Either the language is wrong or your Question/Conclusion is wrong

I suggest to read and understand -- besides the Wien2k manual --  also some 
basic textbooks on the subject, for example
  Richard Martin, Electronic structure, Cambridge
  Jürgen Kübler, Theory of itinerant electron magnetism, Oxford
to avoid any misunderstandings.

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 Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Sonntag, 27. November 2016 23:12
An: wien@zeus.theochem.tuwien.ac.at
Betreff: [Wien] How to include the localized d orbitals in the atomic spheres?

Dear wien users

The orbital potential in DFT+U and EECE for localized orbitals will be included 
only inside the atomic spheres .

To include these localized orbitals, we need a value for energy cut off larger 
than -6 Ry (maybe -2 Ry ).

Is it the only way to include the localized orbitals in the atomic spheres 
since we can't reduce the Rmt values much.

Best regards



--
Mr: A.Reggad
Laboratoire de Génie Physique
Université Ibn Khaldoun - Tiaret
Algerie


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Re: [Wien] Discrepancy in the simulation of the paramagnetic state

2016-11-27 Thread Fecher, Gerhard 
I hope you agree that Pt is paramagnetic
I did two calculations for Pt, one was  spin polarized the other not.
The results are identical, no resulting magnetic moment (indeed, I started with 
one in the spin polarized case), did I play a trick or did Wien2k play a trick ?
but may be Wien2k can not be used to calculate the electronic structure of Pt, 
because it is paramagnetic (Pt, not Wien2k !).

I hope you agree that Pt is paramagnetic even at Zero temperature.
why do I need to include temperature effects to calculate the ground state of 
Pt (at 0 K, where else) ?
... and what should MtC calculations tell me about it ?

Remark 1:
Calculations may be  "spin polarized" (LSDA) or not (LDA) or they may be even 
more sophisticated "non-colinear spin polarized" or they may be for "disordred 
local moments"
or for "spin spirals", or ???,  just to name some.

Remark 2:
Materials may be diamagnetic, paramagnetic (Langevin, Pauli, van Vleck), 
ferromagnetic (localised moments, itinerant), ferrimagnetic (collinear, 
non-collinear), etc..

Therefore, I repeat my question:   How do you distinguish diamagnetic, 
paramagnetic, ferromagnetic, and ... states ?

The answer is for you, not for me.

I tried to calculate for Pt using Hohenberg Kohn DFT, but I could not find the 
functional, all I found was some approximation using wave functions.
Don't worry I will not ask a question about it ;-)

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 Xavier 
Rocquefelte [xavier.rocquefe...@univ-rennes1.fr]
Gesendet: Sonntag, 27. November 2016 12:46
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] Discrepancy in the simulation of the paramagnetic state

Just to add one more point to this funny discussion, the term
"paramagnetic" is sometimes used in the DFT litterature in an improper way.

It could clearly lead to misunderstanding for researchers who do not
know so much on how magnetic properties could evolve with temperature
and applied magnetic field. When you see in a paper "paramagnetic state"
simulated using DFT ... it is NOT paramagnetic at all, it is simply a
trick which must be considered with care as previously mentionned by
Peter, Eliane and Martin.

If you want to simulate a paramagnetic state you need to include the
temperature effects, i.e. you should consider the spin dynamics and the
competition between magnetic exchange interactions and thermal
fluctuations. This could be done, at least, using Monte-Carlo
calculations based on an effective hamiltonian constructed on top of DFT
parameters (including magnetic exchange and anisotropy at least).

Best Regards

Xavier




Le 27/11/2016 à 10:01, Fecher, Gerhard a écrit :
> How do you distinguish a diamagnetic, a paramagnetic, a ferromagnetic, and an 
> antiferromagnetic state.
>
> Think !
>
> This will answer your question, hopefully.
>
> 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 
> Abderrahmane Reggad [jazai...@gmail.com]
> Gesendet: Samstag, 26. November 2016 22:30
> An: wien@zeus.theochem.tuwien.ac.at
> Betreff: Re: [Wien] Discrepancy in the simulation of the paramagnetic state
>
> Thank you Prof Blaha for your quick answer.
>
> The Ni atom is 3d transition metal . But my question is about the simulation 
> of the paramagnetic state. There are many people that considere that the 
> paramagnetic state is the non-spin polarierd one and the magnetic moment is 
> zero, but you say no and the magnetic moments exist in arbitrary directions 
> and my quoting is about that.
>
> I have given 2 examples for that discrepancy with your statement.
>
> Best regards
> --
> Mr: A.Reggad
> Laboratoire de Génie Physique
> Université Ibn Khaldoun - Tiaret
> Algerie
>
>
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Re: [Wien] How to include the localized d orbitals in the atomic spheres?

2016-11-27 Thread Laurence Marks 
Huh?! This is not right.

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


On Nov 27, 2016 16:12, "Abderrahmane Reggad"  wrote:

> Dear wien users
>
> The orbital potential in DFT+U and EECE for localized orbitals will be
> included only inside the atomic spheres .
>
> To include these localized orbitals, we need a value for energy cut off
> larger than -6 Ry (maybe -2 Ry ).
>
> Is it the only way to include the localized orbitals in the atomic spheres
> since we can't reduce the Rmt values much.
>
> Best regards
>
>
>
> --
> Mr: A.Reggad
> Laboratoire de Génie Physique
> Université Ibn Khaldoun - Tiaret
> Algerie
>
>
>
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Re: [Wien] it possible to apply first DFT+U and then mBJ+U?

2016-11-27 Thread Xavier Rocquefelte 

Dear Bhamu

In the present case, you are dealing with Ag+ ions and thus a d10 
electronic configuration for silver.


In such a case applying a Hubbard correction will mainly lead to correct 
the position of the Ag(4d) states which are all occupied and below the 
O(2p) band. It should not affect so much the band gap. Do you have the 
band gap values when doing PBE only?


I would recommend to do:

- PBE

- PBE+mBJ

- and if you want to see the impact of the proper description of the 4d 
band of silver which is too high in energy when doing PBE only, you can 
apply an Hubbard term


You must also consider the impact of relativistic treatment. For silver, 
the spin-orbit coupling will lead to split the p1/2 and p3/2 states 
which could contribute to the conduction band.


Best Regards

Xavier


Le 27/11/2016 à 16:19, Dr. K. C. Bhamu a écrit :


Dear experts
I did a calculation for hexagonal AgAlO2 and found that if I do first 
PBE+U and then apply mBJ+ U, it give smart band gap value which is 
very close to experimental band gap.


But I do not know whether we can apply this U twice or not.
The DFT+U calculation underestimates and only mBJ slightly 
overestimate the experimental band gap for this system.


I did the calculation for -ec 0.1 -cc 0.0002 -fc 2 (setrmt -r 5).

Any comment will be helpful.

Sincerely
Bhamu



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[Wien] it possible to apply first DFT+U and then mBJ+U?

2016-11-27 Thread Dr. K. C. Bhamu 
Dear experts
I did a calculation for hexagonal AgAlO2 and found that if I do first PBE+U
and then apply mBJ+ U, it give smart band gap value which is very close to
experimental band gap.

But I do not know whether we can apply this U twice or not.
The DFT+U calculation underestimates and only mBJ slightly overestimate the
experimental band gap for this system.

I did the calculation for -ec 0.1 -cc 0.0002 -fc 2 (setrmt -r 5).

Any comment will be helpful.

Sincerely
Bhamu
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Re: [Wien] Discrepancy in the simulation of the paramagnetic state

2016-11-27 Thread Fecher, Gerhard 
How do you distinguish a diamagnetic, a paramagnetic, a ferromagnetic, and an 
antiferromagnetic state.

Think !

This will answer your question, hopefully.

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 Abderrahmane 
Reggad [jazai...@gmail.com]
Gesendet: Samstag, 26. November 2016 22:30
An: wien@zeus.theochem.tuwien.ac.at
Betreff: Re: [Wien] Discrepancy in the simulation of the paramagnetic state

Thank you Prof Blaha for your quick answer.

The Ni atom is 3d transition metal . But my question is about the simulation of 
the paramagnetic state. There are many people that considere that the 
paramagnetic state is the non-spin polarierd one and the magnetic moment is 
zero, but you say no and the magnetic moments exist in arbitrary directions and 
my quoting is about that.

I have given 2 examples for that discrepancy with your statement.

Best regards
--
Mr: A.Reggad
Laboratoire de Génie Physique
Université Ibn Khaldoun - Tiaret
Algerie


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Re: [Wien] Discrepancy in the simulation of the paramagnetic state

2016-11-27 Thread E.A.Moore 
In the paramagnetic state, as Prof. Blaha says, the atoms still have magnetic 
moments but they are randomly oriented. This arises when the thermal energy is 
sufficient to overcome the spin-spin coupling. I would expect a calculation on 
Gd at 0K to give you a ferromagnetic state with very small spin-spin coupling. 
You can check the coupling by a run with one spin reversed.


I am not convinced you can model a paramagnetic state with a DFT calculation 
and zero moments is not a good model. Your second example reads as though it is 
reporting experimental results on the magnetisation and does not seem to 
provide a model for calculations.


I would also agree with Prof. Blaha about the factors influencing efg. 
Interatomic distance is very important in calculating this.

Elaine A. Moore
The Open University
UK


From: Wien  on behalf of Abderrahmane 
Reggad 
Sent: 26 November 2016 21:30
To: wien@zeus.theochem.tuwien.ac.at
Subject: Re: [Wien] Discrepancy in the simulation of the paramagnetic state


Thank you Prof Blaha for your quick answer.

The Ni atom is 3d transition metal . But my question is about the simulation of 
the paramagnetic state. There are many people that considere that the 
paramagnetic state is the non-spin polarierd one and the magnetic moment is 
zero, but you say no and the magnetic moments exist in arbitrary directions and 
my quoting is about that.

I have given 2 examples for that discrepancy with your statement.

Best regards
--
Mr: A.Reggad
Laboratoire de Génie Physique
Université Ibn Khaldoun - Tiaret
Algerie


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