Re: [Pw_forum] GGA+U

[Giuseppe Mattioli]

Dear Sohail Ahmad
Before all why 5.0.1? It is not only an outdated version (10/05/2012!) which 
nobody has anymore interest in debugging/improving, but it is also the 
first version of the 5.x release, and it is therefore probably full of bugs 
that have been corrected later. If you want to stick to 5.x, then use at 
least the latest 5.4.0 version, or switch to 6.0.

>  Dear All QE usersI wish to study ScN using GGA+U.I am using QE-5.0.1,If I 
> understood correctly , I need to modifyPW/set_hubbard_l.f90 and
> PW/tabd.f90

Yes, you should add data for Sc 

PW/src/tabd.f90

add

  CASE( 'Sc' )
hubbard_occ = 1.d0

just before

  CASE( 'Ti', 'Zr', 'Hf' )
hubbard_occ = 2.d0


/Espresso/5.4.0/Modules/set_hubbard_l.f90

 CASE( 'Ti', 'V',  'Cr', 'Mn', 'Fe', 'Co', 'Ni', 'Cu', 'Zn', &
   'Zr', 'Nb', 'Mo', 'Tc', 'Ru', 'Rh', 'Pd', 'Ag', 'Cd', &
   'Hf', 'Ta', 'W',  'Re', 'Os', 'Ir', 'Pt', 'Au', 'Hg'  )

add 'Sc' to the list -->

 CASE( 'Ti', 'V',  'Cr', 'Mn', 'Fe', 'Co', 'Ni', 'Cu', 'Zn', &
   'Zr', 'Nb', 'Mo', 'Tc', 'Ru', 'Rh', 'Pd', 'Ag', 'Cd', &
   'Hf', 'Ta', 'W',  'Re', 'Os', 'Ir', 'Pt', 'Au', 'Hg', &
   'Sc'  )

> exact value of U for ScN ?

Of course nobody knows! You should estimate it, there are several 
(semiempirical or self-consistent) ways. Read this to start:
Himmetoglu, B.; Floris, A.; de Gironcoli, S.; Cococcioni, M. Int. J. Quantum 
Chem. 2014, 114, 14-49

HTH
Giuseppe

On Saturday, February 25, 2017 07:08:19 PM Sohail Ahmad wrote:
>  Dear All QE usersI wish to study ScN using GGA+U.I am using QE-5.0.1,If I 
> understood correctly , I need to modifyPW/set_hubbard_l.f90 and
> PW/tabd.f90 I found the file PW/src/tabd.f90 but don't see set_hubbard_l.f90 
> in PW/src 1.   Can any one explain where can I find this ?2.What
> exact line/values need to be modified ?3.   exact value of U for ScN ? Any 
> further guideline regarding input file is appreciated
> Best WishesSohail AhmadKing Khalid UniversitySaudi Arabia


- Article premier - Les hommes naissent et demeurent
libres et égaux en droits. Les distinctions sociales
ne peuvent être fondées que sur l'utilité commune
- Article 2 - Le but de toute association politique
est la conservation des droits naturels et 
imprescriptibles de l'homme. Ces droits sont la liberté,
la propriété, la sûreté et la résistance à l'oppression.


   Giuseppe Mattioli
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
   v. Salaria Km 29,300 - C.P. 10
   I 00015 - Monterotondo Stazione (RM), Italy
   Tel + 39 06 90672342 - Fax +39 06 90672316
   E-mail: 
   http://www.ism.cnr.it/en/staff/giuseppe-mattioli/
   ResearcherID: F-6308-2012

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[Pw_forum] GGA+U

[Sohail Ahmad]

 Dear All QE usersI wish to study ScN using GGA+U.I am using QE-5.0.1,If I 
understood correctly , I need to modifyPW/set_hubbard_l.f90 and PW/tabd.f90
I found the file PW/src/tabd.f90 but don't see set_hubbard_l.f90 in PW/src 1.   
Can any one explain where can I find this ?2.    What exact line/values need to 
be modified ?3.   exact value of U for ScN ?
Any further guideline regarding input file is appreciated
Best WishesSohail AhmadKing Khalid UniversitySaudi Arabia
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[Pw_forum] GGA+U band structurs

[FARAH MARSUSI]

Dear all,

Both of "set_hubbard_l.f90" and also "tabd.f90" are working nicely for both scf 
and nscf runs after editing them for C and F atoms. Therefore, I could get the 
correction to the energy levels and magnetic comment using GGA+U. However, by 
executing bands.in to plot predicted GGA+U bands in desired paths, I have 
received this message: " Error in routine set_hubbard_l (1):   pseudopotential 
not yet inserted"! 

F. Marsusi,

Department of Physics,
Amirkabir University of Technology.​___
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Re: [Pw_forum] GGA+U

[Giuseppe Mattioli]

Dear F. Marsusi

> Is this what one expected always from +U calculations,

As I told you before nothing can be considered as "expected" when you apply the 
U correction to a strongly hybridized sp2 system such as a pi-
conjugated molecule or graphene. In my experience this is not a good idea, 
because you obtain, for example, a higher ionization energy (and this is 
right when you correct LDA/GGA delocalization errors, and in agreement with a 
correction with exact exchange like B3LYP or HSE) but also a lower 
electron affinity (and this is wrong, and the opposite behavior of a correction 
with exact exchange). So you are walking in "terra incognita" where 
nothing can be given for granted.
HTH
Giuseppe

On Friday, February 10, 2017 08:38:37 PM FARAH MARSUSI wrote:
> Dear Giuseppe,
> 
> Many thanks for your quick response. As you have correctly guessed, the 
> system is an organic material (fluorinated graphene). From U=0 to 3.4, M is
> increasing gradually up to the expected value, M remains constant till U=3.6 
> eV, then by increasing U, again M is reduced very soon to zero. Is
> this what one expected always from +U calculations, when goes up further from 
> the optimum U value? From your answer, it is concluded to be a
> strange behavior due to the organic nature of this material.
> 
> Best regards,
> F. Marsusi,
> 
> Amirkabir University of Technology.​
> 
> On Fri, 02/10/2017 08:09 PM, Giuseppe Mattioli  
> wrote:
> > Dear F. Marsusi
> > First of all you are not providing any detail of your system, so we cannot 
> > even guess what is "natural" for it.
> > However, you are using the Hubbard U correction in a semiempirical way, and 
> > there is therefore no way to choose the U value but that reproducing
> > some measured parameter, and not very much to do if unexpected or strange 
> > results appear at a given (unphysical?, problematic?) U value.
> > In my experience the application of U to organic molecules has been always 
> > problematic due to the strong hybridization between C 2s and C 2p
> > orbitals, and to the application of the correction to 2p orbitals only.
> > HTH
> > Giuseppe
> > 
> > On Friday, February 10, 2017 07:25:10 PM FARAH MARSUSI wrote:
> > > Dear all,
> > > 
> > > By GGA+U as implemented in QE, the correct magnetization (M) and band gap 
> > > was obtained. The correct U value for each atom was obtained by
> > > intensive
> > > step by step runs to reach gradually the experimental M value, and 
> > > therefore band gap. All results are OK till now (the U value itself also= 
> > > 3.4
> > > eV
> > > for carbon and fluorine is acceptable ). However, by enlarging the 
> > > obtained U value a bit (to 3.7 eV), the predicted M come back to that of 
> > > pure
> > > GGA. Is it natural, or a problem exist?
> > > 
> > > 
> > > Best regards,
> > > F. Marsusi,
> > 
> > 
> > - Article premier - Les hommes naissent et demeurent
> > libres et égaux en droits. Les distinctions sociales
> > ne peuvent être fondées que sur l'utilité commune
> > - Article 2 - Le but de toute association politique
> > est la conservation des droits naturels et
> > imprescriptibles de l'homme. Ces droits sont la liberté,
> > la propriété, la sûreté et la résistance à l'oppression.
> > 
> > 
> >Giuseppe Mattioli
> >CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
> >v. Salaria Km 29,300 - C.P. 10
> >I 00015 - Monterotondo Stazione (RM), Italy
> >Tel + 39 06 90672342 - Fax +39 06 90672316
> >E-mail: " target="_blank">
> >http://www.ism.cnr.it/en/staff/giuseppe-mattioli/
> >ResearcherID: F-6308-2012
> > 
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> > --
> > This email was Anti Virus checked by Astaro Security Gateway. 
> > http://www.sophos.com


- Article premier - Les hommes naissent et demeurent
libres et égaux en droits. Les distinctions sociales
ne peuvent être fondées que sur l'utilité commune
- Article 2 - Le but de toute association politique
est la conservation des droits naturels et 
imprescriptibles de l'homme. Ces droits sont la liberté,
la propriété, la sûreté et la résistance à l'oppression.


   Giuseppe Mattioli
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
   v. Salaria Km 29,300 - C.P. 10
   I 00015 - Monterotondo Stazione (RM), Italy
   Tel + 39 06 90672342 - Fax +39 06 90672316
   E-mail: 
   http://www.ism.cnr.it/en/staff/giuseppe-mattioli/
   ResearcherID: F-6308-2012

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Re: [Pw_forum] GGA+U

[FARAH MARSUSI]

Dear Giuseppe,

Many thanks for your quick response. As you have correctly guessed, the system 
is an organic material (fluorinated graphene). From U=0 to 3.4, M is increasing 
gradually up to the expected value, M remains constant till U=3.6 eV, then by 
increasing U, again M is reduced very soon to zero. Is this what one expected 
always from +U calculations, when goes up further from the optimum U value? 
From your answer, it is concluded to be a strange behavior due to the organic 
nature of this material.

Best regards,
F. Marsusi,

Amirkabir University of Technology.​
On Fri, 02/10/2017 08:09 PM, Giuseppe Mattioli  
wrote:
> Dear F. Marsusi
> First of all you are not providing any detail of your system, so we cannot 
> even guess what is "natural" for it.
> However, you are using the Hubbard U correction in a semiempirical way, and 
> there is therefore no way to choose the U value but that reproducing some 
> measured parameter, and not very much to do if unexpected or strange results 
> appear at a given (unphysical?, problematic?) U value.
> In my experience the application of U to organic molecules has been always 
> problematic due to the strong hybridization between C 2s and C 2p orbitals, 
> and to the application of the correction to 2p orbitals only.
> HTH
> Giuseppe
> 
> On Friday, February 10, 2017 07:25:10 PM FARAH MARSUSI wrote:
> > Dear all,
> > 
> > By GGA+U as implemented in QE, the correct magnetization (M) and band gap 
> > was obtained. The correct U value for each atom was obtained by intensive
> > step by step runs to reach gradually the experimental M value, and 
> > therefore band gap. All results are OK till now (the U value itself also= 
> > 3.4 eV
> > for carbon and fluorine is acceptable ). However, by enlarging the obtained 
> > U value a bit (to 3.7 eV), the predicted M come back to that of pure
> > GGA. Is it natural, or a problem exist?
> > 
> > 
> > Best regards,
> > F. Marsusi,
> 
> 
> - Article premier - Les hommes naissent et demeurent
> libres et égaux en droits. Les distinctions sociales
> ne peuvent être fondées que sur l'utilité commune
> - Article 2 - Le but de toute association politique
> est la conservation des droits naturels et 
> imprescriptibles de l'homme. Ces droits sont la liberté,
> la propriété, la sûreté et la résistance à l'oppression.
> 
> 
>Giuseppe Mattioli
>CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
>v. Salaria Km 29,300 - C.P. 10
>I 00015 - Monterotondo Stazione (RM), Italy
>Tel + 39 06 90672342 - Fax +39 06 90672316
>E-mail: " target="_blank">
>http://www.ism.cnr.it/en/staff/giuseppe-mattioli/
>ResearcherID: F-6308-2012
> 
> ___
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> 
> --
> This email was Anti Virus checked by Astaro Security Gateway. 
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Re: [Pw_forum] GGA+U

[Giuseppe Mattioli]

Dear F. Marsusi
First of all you are not providing any detail of your system, so we cannot even 
guess what is "natural" for it.
However, you are using the Hubbard U correction in a semiempirical way, and 
there is therefore no way to choose the U value but that reproducing some 
measured parameter, and not very much to do if unexpected or strange results 
appear at a given (unphysical?, problematic?) U value.
In my experience the application of U to organic molecules has been always 
problematic due to the strong hybridization between C 2s and C 2p orbitals, 
and to the application of the correction to 2p orbitals only.
HTH
Giuseppe

On Friday, February 10, 2017 07:25:10 PM FARAH MARSUSI wrote:
> Dear all,
> 
> By GGA+U as implemented in QE, the correct magnetization (M) and band gap was 
> obtained. The correct U value for each atom was obtained by intensive
> step by step runs to reach gradually the experimental M value, and therefore 
> band gap. All results are OK till now (the U value itself also= 3.4 eV
> for carbon and fluorine is acceptable ). However, by enlarging the obtained U 
> value a bit (to 3.7 eV), the predicted M come back to that of pure
> GGA. Is it natural, or a problem exist?
> 
> 
> Best regards,
> F. Marsusi,


- Article premier - Les hommes naissent et demeurent
libres et égaux en droits. Les distinctions sociales
ne peuvent être fondées que sur l'utilité commune
- Article 2 - Le but de toute association politique
est la conservation des droits naturels et 
imprescriptibles de l'homme. Ces droits sont la liberté,
la propriété, la sûreté et la résistance à l'oppression.


   Giuseppe Mattioli
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
   v. Salaria Km 29,300 - C.P. 10
   I 00015 - Monterotondo Stazione (RM), Italy
   Tel + 39 06 90672342 - Fax +39 06 90672316
   E-mail: 
   http://www.ism.cnr.it/en/staff/giuseppe-mattioli/
   ResearcherID: F-6308-2012

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[Pw_forum] GGA+U

[FARAH MARSUSI]

Dear all,

By GGA+U as implemented in QE, the correct magnetization (M) and band gap was 
obtained. The correct U value for each atom was obtained by intensive step by 
step runs to reach gradually the experimental M value, and therefore band gap. 
All results are OK till now (the U value itself also= 3.4 eV for carbon and 
fluorine is acceptable ). However, by enlarging the obtained U value a bit (to 
3.7 eV), the predicted M come back to that of pure GGA. 
Is it natural, or a problem exist?


Best regards,
F. Marsusi,


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Re: [Pw_forum] gga+u CALCULATION

[Kajal Jindal]

Thanks a lot sir for the clarification

On 17-Jan-2017 2:58 pm, "Giuseppe Mattioli" 
wrote:

>
> Dear Kajal Jindal
> It is only a matter of labels... The first implementation was an LDA+U
> one, and the input key was named lda_plus_U after that. But if your
> underlying
> functional is a GGA one, e.g., PBE, you are performing GGA+U (or DFT+U,
> that is a generalization) even if the input key is still called (for
> laziness
> or compatibility, I don't know... :-) ) lda_plus_U.
> HTH
> Giuseppe
>
> On Tuesday, January 17, 2017 10:29:36 AM Kajal Jindal wrote:
> > Dear all,
> >
> > I want to perform GGA+U calculation on quantum espresso. The
> input_PW.html
> > file shows that for DFT+U calculations i have to set lda_plus_U=.true.
> But
> > nothing is given about GGA+U.
> >
> > KIndly help.
> > What are the parameters i need to introduce for GGA+U calculation?
> >
> > Thanking You,
> > Kajal Jindal
> > University of Delhi
> > Delhi, INDIA
>
> 
> - Article premier - Les hommes naissent et demeurent
> libres et égaux en droits. Les distinctions sociales
> ne peuvent être fondées que sur l'utilité commune
> - Article 2 - Le but de toute association politique
> est la conservation des droits naturels et
> imprescriptibles de l'homme. Ces droits sont la liberté,
> la propriété, la sûreté et la résistance à l'oppression.
> 
>
>Giuseppe Mattioli
>CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
>v. Salaria Km 29,300 - C.P. 10
>I 00015 - Monterotondo Stazione (RM), Italy
>Tel + 39 06 90672342 - Fax +39 06 90672316
>E-mail: 
>http://www.ism.cnr.it/en/staff/giuseppe-mattioli/
>ResearcherID: F-6308-2012
>
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Re: [Pw_forum] gga+u CALCULATION

[Giuseppe Mattioli]

Dear Kajal Jindal
It is only a matter of labels... The first implementation was an LDA+U one, and 
the input key was named lda_plus_U after that. But if your underlying 
functional is a GGA one, e.g., PBE, you are performing GGA+U (or DFT+U, that is 
a generalization) even if the input key is still called (for laziness 
or compatibility, I don't know... :-) ) lda_plus_U.
HTH
Giuseppe

On Tuesday, January 17, 2017 10:29:36 AM Kajal Jindal wrote:
> Dear all,
> 
> I want to perform GGA+U calculation on quantum espresso. The input_PW.html
> file shows that for DFT+U calculations i have to set lda_plus_U=.true. But
> nothing is given about GGA+U.
> 
> KIndly help.
> What are the parameters i need to introduce for GGA+U calculation?
> 
> Thanking You,
> Kajal Jindal
> University of Delhi
> Delhi, INDIA


- Article premier - Les hommes naissent et demeurent
libres et égaux en droits. Les distinctions sociales
ne peuvent être fondées que sur l'utilité commune
- Article 2 - Le but de toute association politique
est la conservation des droits naturels et 
imprescriptibles de l'homme. Ces droits sont la liberté,
la propriété, la sûreté et la résistance à l'oppression.


   Giuseppe Mattioli
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
   v. Salaria Km 29,300 - C.P. 10
   I 00015 - Monterotondo Stazione (RM), Italy
   Tel + 39 06 90672342 - Fax +39 06 90672316
   E-mail: 
   http://www.ism.cnr.it/en/staff/giuseppe-mattioli/
   ResearcherID: F-6308-2012

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[Pw_forum] gga+u CALCULATION

[Kajal Jindal]

Dear all,

I want to perform GGA+U calculation on quantum espresso. The input_PW.html
file shows that for DFT+U calculations i have to set lda_plus_U=.true. But
nothing is given about GGA+U.

KIndly help.
What are the parameters i need to introduce for GGA+U calculation?

Thanking You,
Kajal Jindal
University of Delhi
Delhi, INDIA
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Re: [Pw_forum] GGA+U for Germanium, Tin and Silicon

[Giuseppe Mattioli]

Dear Dhirendra

The hubbard_l and hubbard_occ variables identify the angular momentum channel 
and starting occupation of the electronic shell you are going to correct 
with U, respectively. In the case of Si, Ge and Sn the values are usually set 
to the same values of C (1 and 2.0), but remember that this correction 
of the p orbitals can, in principle, affect (with weird results) the behavior 
of s orbitals, which in covalent compounds like molecules (C), and group 
IV semiconductors (C, Si, Ge) are strongly mixed with p orbitals in the 
so-called hybridized sp, sp2, sp3,... orbitals.
HTH

Giuseppe

On Wednesday, May 20, 2015 11:32:31 PM DHIRENDRA VAIDYA wrote:
> Hi all
> 
> I am trying to use GGA+U in PWSCF. A similar approach as mentioned in
> http://dx.doi.org/10.1063/1.3625939
> 
> Ge, Sn and Si are not listed in flib/set_hubbard_l.f90 and src/tabd.f90.
> Can anyone suggest the 'hubbard_l' value to be set in set_hubbard_l.f90 and
> 'hubbard_occ' in tabd.f90 for Ge, Sn and Si?
> 
> Thanks
> --
> Dhirendra


- Article premier - Les hommes naissent et demeurent
libres et ègaux en droits. Les distinctions sociales
ne peuvent être fondèes que sur l'utilitè commune
- Article 2 - Le but de toute association politique
est la conservation des droits naturels et 
imprescriptibles de l'homme. Ces droits sont la libertè,
la propriètè, la sùretè et la rèsistance à l'oppression.


   Giuseppe Mattioli
   CNR - ISTITUTO DI STRUTTURA DELLA MATERIA   
   v. Salaria Km 29,300 - C.P. 10
   I 00015 - Monterotondo Stazione (RM), Italy
   Tel + 39 06 90672836 - Fax +39 06 90672316
   E-mail: 
   http://www.ism.cnr.it/english/staff/mattiolig
   ResearcherID: F-6308-2012

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[Pw_forum] GGA+U for Germanium, Tin and Silicon

[DHIRENDRA VAIDYA]

Hi all

I am trying to use GGA+U in PWSCF. A similar approach as mentioned in
http://dx.doi.org/10.1063/1.3625939

Ge, Sn and Si are not listed in flib/set_hubbard_l.f90 and src/tabd.f90.
Can anyone suggest the 'hubbard_l' value to be set in set_hubbard_l.f90 and
'hubbard_occ' in tabd.f90 for Ge, Sn and Si?

Thanks
--
Dhirendra
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[Pw_forum] GGA+U: Sensitivity of occupation matrix

[Stefano Fabris]

Dear Chan-Woo Lee,

if I understand correctly your mail, you are experiencing a common problem in 
DFT+U calculations. The issue is related to the existence of several local 
minima of the electronic solution present for the SAME crystal structure. One 
example of this for the case of FeO is provided in DFT+U example of the QE 
distribution (example 25 if I remember correctly). In that case, you can reach 
two electronic self-consistent solutions: one in which one electron is 
distributed over three d orbitals with almost equal occupancy, the other (with 
lower energy) in which the electron occupies only one d orbital. The 
calculation converges to one or the other depending on the initial values of 
the occupations. See the effect of starting_ns_eigenvalue

In my experience, the case of cerium oxides is even more delicate (and more 
frustrating the more you move towards complex crystal structures), but the way 
out is the same. Always carefully check the final occupancies, and in case of 
fractional occupations, play with starting_ns_eigenvalue and try to reach a 
lower energy solution with interger occupations on the localized orbitals 
entering the U term.

Hope this helps.

Stefano

On Feb 2, 2012, at 11:32 PM, Chan-Woo Lee wrote:

> Dear QE developers and users:
>  
> This is kind of follow-up question of my previous post: 
> http://www.democritos.it/pipermail/pw_forum/2011-December/022823.html
>  
> I found that current Ce psp has some critical problems (for both CeO2 and 
> Ce2O3) and tried to modify the psp. In doing so, I found Ce psp from Prof. 
> Fabris (http://www.democritos.it/~fabris/Ce4_ps_f1d1-pbe-rc1.0.uspp.UPF ) and 
> tried it with current O psp. The Ce psp is ultrasoft and the O psp is RRKJ. 
> Both use PBE functionals.
>  
> In working with the psp, I found interesting results. I tried two cases: 1) 
> SCF without any atomic relaxation 2) RELAX. I use QE 4.3.2 and Effective U is 
> chosen as 5.0. Initial structures are adopted from 
> http://prb.aps.org/abstract/PRB/v75/i4/e045121 . As relax from case 2) 
> doesn?t do much, final structures from two cases are identical.
>  
> While the structures are identical, occupation of f orbitals are different 
> and DOS are also not the same. For 1) case, occupation is almost 1.0 (~0.9) 
> at single orbital state which is desirable, I think. Also, DOS shows that 
> there is no partially filled f states near Fermi level which is the case for 
> conventional DFT. So, Ce2O3 is predicted to be insulating. For 2) case, 
> occupations are somewhat even: 0.23, 0.26, 0.29, and 0.12.. Also, electronic 
> structure doesn?t change that much and there is still partially filled f 
> states. Same atomic structures but totally difference electronic structures?
>  
> While I tried to understand and explain this to myself, I can?t find any good 
> answers for this. I am currently testing ?starting_ns_eigenvalue? and 
> ?mixing_fixed_ns? to see forcing certain occupations will be helpful or not.. 
> but I am not sure.
>  
> Any comments or suggestions
>  
> ---
> Chan-Woo Lee, Ph.D.
> Postdoctoral Research Associate
>  
> Department of Chemistry
> University of Pennsylvania
> 231 South 34th Street
> Philadelphia, PA 19104-6323 
> 
> 
>  
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum

---
Stefano Fabris
CNR-IOM DEMOCRITOS Simulation Center and 
SISSA - Scuola Internazionale Superiore di Studi Avanzati
tel: @SISSA +39 040 3787-872 @Elettra: +39 040 3758-735
email: fabris at sissa.it  
http://people.sissa.it/~fabris
---

[Pw_forum] GGA+U: Sensitivity of occupation matrix

[Chan-Woo Lee]

Dear QE developers and users:

 

This is kind of follow-up question of my previous post:
http://www.democritos.it/pipermail/pw_forum/2011-December/022823.html

 

I found that current Ce psp has some critical problems (for both CeO2 and
Ce2O3) and tried to modify the psp. In doing so, I found Ce psp from Prof.
Fabris ( http://www.democritos.it/~fabris/Ce4_ps_f1d1-pbe-rc1.0.uspp.UPF )
and tried it with current O psp. The Ce psp is ultrasoft and the O psp is
RRKJ. Both use PBE functionals. 

 

In working with the psp, I found interesting results. I tried two cases: 1)
SCF without any atomic relaxation 2) RELAX. I use QE 4.3.2 and Effective U
is chosen as 5.0. Initial structures are adopted from
http://prb.aps.org/abstract/PRB/v75/i4/e045121 . As relax from case 2)
doesn't do much, final structures from two cases are identical. 

 

While the structures are identical, occupation of f orbitals are different
and DOS are also not the same. For 1) case, occupation is almost 1.0 (~0.9)
at single orbital state which is desirable, I think. Also, DOS shows that
there is no partially filled f states near Fermi level which is the case for
conventional DFT. So, Ce2O3 is predicted to be insulating. For 2) case,
occupations are somewhat even: 0.23, 0.26, 0.29, and 0.12.. Also, electronic
structure doesn't change that much and there is still partially filled f
states. Same atomic structures but totally difference electronic structures.

 

While I tried to understand and explain this to myself, I can't find any
good answers for this. I am currently testing "starting_ns_eigenvalue" and
"mixing_fixed_ns" to see forcing certain occupations will be helpful or
not.. but I am not sure. 

 

Any comments or suggestions.???

 

---
Chan-Woo Lee, Ph.D.

Postdoctoral Research Associate

 

Department of Chemistry
University of Pennsylvania
231 South 34th Street
Philadelphia, PA 19104-6323 




 

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[Pw_forum] GGA+U

[Matteo Cococcioni]

S. K. S. wrote:
>
>  Dear QE USERS,
>  
>  Yes, the code works fine when I change the name
>  of element from "eu" to "Eu" inside the pseudopotential file.
>  Thank you all for your kind reply.
>
>  One more question : what is Hubbard_alpha ?
>   Is this Lagrange multipliers? What is its typical value?

typical value: -0.2 to 0.2 in most case should work. center around 0 and 
check linearity of occupations
with alpha.

>   Is this possible to specify J & U both, in the input file of the 
> newest version
>   of QE code or  is this always U_eff ?
>  
>  regards,
>  Saha SK
>
>
> 
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>   


-- 
%%%
Matteo Cococcioni
Department of Chemical Engineering and Materials Science,
University of Minnesota
421 Washington Av. SE
Minneapolis, MN 55455
Tel. +1 612 624 9056Fax +1 612 626 7246
%%% 

[Pw_forum] GGA+U

[Matteo Cococcioni]

S. K. S. wrote:
>
>  Dear QE USERS,
>  
>  Yes, the code works fine when I change the name
>  of element from "eu" to "Eu" inside the pseudopotential file.
>  Thank you all for your kind reply.
>
>  One more question : what is Hubbard_alpha ?
>   Is this Lagrange multipliers? What is its typical value?

yes, it's used to compute U (see PRB 71 035105 (2005))

>   Is this possible to specify J & U both, in the input file of the 
> newest version
>   of QE code or  is this always U_eff ?

always U_eff. the functional with U and J was never implemented on 
official version of the code.

Matteo

>  
>  regards,
>  Saha SK
>
>
> 
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>   


-- 
%%%
Matteo Cococcioni
Department of Chemical Engineering and Materials Science,
University of Minnesota
421 Washington Av. SE
Minneapolis, MN 55455
Tel. +1 612 624 9056Fax +1 612 626 7246
%%% 

[Pw_forum] GGA+U

[S. K. S.]

 Dear QE USERS,

 Yes, the code works fine when I change the name
 of element from "eu" to "Eu" inside the pseudopotential file.
 Thank you all for your kind reply.

 One more question : what is Hubbard_alpha ?
  Is this Lagrange multipliers? What is its typical value?
  Is this possible to specify J & U both, in the input file of the newest
version
  of QE code or  is this always U_eff ?

 regards,
 Saha SK
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[Pw_forum] GGA+U

[Paolo Giannozzi]

Matteo Cococcioni wrote:

> make sure the name of the element is a) present (not sure whether 
> the code would stop or not without the name)

I don't think it would stop, but the name of the element is reprinted
on output, so it is easy to verify

P.
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy

[Pw_forum] GGA+U

[Giuseppe Mattioli]

Dear all
I would like to suggest a very simple solution: all the elements could be 
inserted in both the set_hubbard_l.f90 and tabd.f90 files in the most 
straightforward way. If there is anybody who wants something more exotic he 
will change his files by hand.
yours
Giuseppe


On Tuesday 13 July 2010 09:35:19 Gabriele Sclauzero wrote:
> Dear Saha,
>
>this question has been asked many times in this forum so far (so many
> that it could deserve to be included in the FAQ, perhaps), so that you may
> get your reply by simply browsing in the forum archives. Very briefly, the
> code needs to know which electron manyfold of the "Hubbard" atomic species
> should be treated with the +U correction and what is the occupation of that
> electronic shell in the atom. This information has been already hardcoded
> for the most common elements. Evidently, Eu is not among those. You have to
> manually modify files set_hubbard_l.f90 and tabd.f90 (in the PW folder)
> according to what you think reasonable for your case.
>
>
> Regards,
>
> GS
>
> Il giorno 13/lug/2010, alle ore 01.04, S. K. S. ha scritto:
> > Dear QE Users,
> >
> > I got the following error while used GGA+U for EuO:
> >
> > 
> > %
> >% from set_hubbard_l : error # 1
> >  pseudopotential not yet inserted
> > 
> > %
> >%
> >
> >  stopping ...
> >
> > Inside source file, I have found that "Eu" is mentioned. However, I do
> > not understand the meaning of inserting a pseudopotential.
> >
> > Thanks in advance for a helpful explanation.
> >
> > With best regards,
> >
> > Saha SK
> > R&D Assistant
> > JNCASR
> > Bangalore 560012
> >
> > ___
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://www.democritos.it/mailman/listinfo/pw_forum
>
> ? Gabriele Sclauzero, EPFL SB ITP CSEA
>PH H2 462, Station 3, CH-1015 Lausanne



-- 

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? ?Giuseppe Mattioli ? ? ? ? ? ? ? ? ? ? ? ? ? ?
? ?CNR - ISTITUTO DI STRUTTURA DELLA MATERIA ? 
? ?v. Salaria Km 29,300 - C.P. 10 ? ? ? ? ? ? ? ?
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? ?Tel + 39 06 90672836 - Fax +39 06 90672316 ? ?
? ?E-mail: 

[Pw_forum] GGA+U

[Gabriele Sclauzero]

Il giorno 13/lug/2010, alle ore 12.07, Gabriele Sclauzero ha scritto:

> 
> Sorry, I didn't read your mail carefully. Actually the case of Eu is already 
> included in both set_hubbard_l and tabd.
> 
> So the problem should be another one.  Which version of QE are you using? If 
> it's not 4.1, please update to 4.2 and try again.

Sorry, I was actually  meaning "if it's 4.1"...

GS

> 
> Thanks,
> 
> GS
> 
> Il giorno 13/lug/2010, alle ore 09.35, Gabriele Sclauzero ha scritto:
> 
>> Dear Saha,
>> 
>>this question has been asked many times in this forum so far (so many 
>> that it could deserve to be included in the FAQ, perhaps), so that you may 
>> get your reply by simply browsing in the forum archives. 
>> Very briefly, the code needs to know which electron manyfold of the 
>> "Hubbard" atomic species should be treated with the +U correction and what 
>> is the occupation of that electronic shell in the atom. This information has 
>> been already hardcoded for the most common elements. Evidently, Eu is not 
>> among those. You have to manually modify files set_hubbard_l.f90 and 
>> tabd.f90 (in the PW folder) according to what you think reasonable for your 
>> case.
>> 
>> 
>> Regards,
>> 
>> GS
>> 
>> Il giorno 13/lug/2010, alle ore 01.04, S. K. S. ha scritto:
>> 
>>>   
>>> 
>>> Dear QE Users,
>>> 
>>> I got the following error while used GGA+U for EuO:
>>> 
>>>  
>>> %%
>>>  from set_hubbard_l : error # 1
>>>  pseudopotential not yet inserted
>>>  
>>> %%
>>> 
>>>  stopping ...
>>> 
>>> Inside source file, I have found that "Eu" is mentioned. However, I do not 
>>> understand 
>>> the meaning of inserting a pseudopotential. 
>>> 
>>> Thanks in advance for a helpful explanation.  
>>> 
>>> With best regards,
>>> 
>>> Saha SK 
>>> R&D Assistant
>>> JNCASR
>>> Bangalore 560012
>>> 
>>> ___
>>> Pw_forum mailing list
>>> Pw_forum at pwscf.org
>>> http://www.democritos.it/mailman/listinfo/pw_forum
>> 
>> 
>> ? Gabriele Sclauzero, EPFL SB ITP CSEA
>>PH H2 462, Station 3, CH-1015 Lausanne
>> 
>> ___
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://www.democritos.it/mailman/listinfo/pw_forum
> 
> 
> ? Gabriele Sclauzero, EPFL SB ITP CSEA
>PH H2 462, Station 3, CH-1015 Lausanne
> 
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum


? Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

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[Pw_forum] GGA+U

[Gabriele Sclauzero]

Sorry, I didn't read your mail carefully. Actually the case of Eu is already 
included in both set_hubbard_l and tabd.

So the problem should be another one.  Which version of QE are you using? If 
it's not 4.1, please update to 4.2 and try again.

Thanks,

GS

Il giorno 13/lug/2010, alle ore 09.35, Gabriele Sclauzero ha scritto:

> Dear Saha,
> 
>this question has been asked many times in this forum so far (so many that 
> it could deserve to be included in the FAQ, perhaps), so that you may get 
> your reply by simply browsing in the forum archives. 
> Very briefly, the code needs to know which electron manyfold of the "Hubbard" 
> atomic species should be treated with the +U correction and what is the 
> occupation of that electronic shell in the atom. This information has been 
> already hardcoded for the most common elements. Evidently, Eu is not among 
> those. You have to manually modify files set_hubbard_l.f90 and tabd.f90 (in 
> the PW folder) according to what you think reasonable for your case.
> 
> 
> Regards,
> 
> GS
> 
> Il giorno 13/lug/2010, alle ore 01.04, S. K. S. ha scritto:
> 
>>   
>> 
>> Dear QE Users,
>> 
>> I got the following error while used GGA+U for EuO:
>> 
>>  
>> %%
>>  from set_hubbard_l : error # 1
>>  pseudopotential not yet inserted
>>  
>> %%
>> 
>>  stopping ...
>> 
>> Inside source file, I have found that "Eu" is mentioned. However, I do not 
>> understand 
>> the meaning of inserting a pseudopotential. 
>> 
>> Thanks in advance for a helpful explanation.  
>> 
>> With best regards,
>> 
>> Saha SK 
>> R&D Assistant
>> JNCASR
>> Bangalore 560012
>> 
>> ___
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://www.democritos.it/mailman/listinfo/pw_forum
> 
> 
> ? Gabriele Sclauzero, EPFL SB ITP CSEA
>PH H2 462, Station 3, CH-1015 Lausanne
> 
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum


? Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

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[Pw_forum] GGA+U

[Gabriele Sclauzero]

Dear Saha,

   this question has been asked many times in this forum so far (so many that 
it could deserve to be included in the FAQ, perhaps), so that you may get your 
reply by simply browsing in the forum archives. 
Very briefly, the code needs to know which electron manyfold of the "Hubbard" 
atomic species should be treated with the +U correction and what is the 
occupation of that electronic shell in the atom. This information has been 
already hardcoded for the most common elements. Evidently, Eu is not among 
those. You have to manually modify files set_hubbard_l.f90 and tabd.f90 (in the 
PW folder) according to what you think reasonable for your case.


Regards,

GS

Il giorno 13/lug/2010, alle ore 01.04, S. K. S. ha scritto:

>   
> 
> Dear QE Users,
> 
> I got the following error while used GGA+U for EuO:
> 
>  
> %%
>  from set_hubbard_l : error # 1
>  pseudopotential not yet inserted
>  
> %%
> 
>  stopping ...
> 
> Inside source file, I have found that "Eu" is mentioned. However, I do not 
> understand 
> the meaning of inserting a pseudopotential. 
> 
> Thanks in advance for a helpful explanation.  
> 
> With best regards,
> 
> Saha SK 
> R&D Assistant
> JNCASR
> Bangalore 560012
> 
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum


? Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

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[Pw_forum] GGA+U

[Matteo Cococcioni]

Dear Saha,

maybe the problem is a "formal" one. Open the PP file (maybe you want to 
share it with this community) and make sure
the name of the element is a) present (not sure whether the code would 
stop or not without the name);
b) written exactly 'Eu'. That is what the code has instructions for.

Matteo



Gabriele Sclauzero wrote:
>
> Sorry, I didn't read your mail carefully. Actually the case of Eu is 
> already included in both set_hubbard_l and tabd.
>
> So the problem should be another one.  Which version of QE are you 
> using? If it's not 4.1, please update to 4.2 and try again.
>
> Thanks,
>
> GS
>
> Il giorno 13/lug/2010, alle ore 09.35, Gabriele Sclauzero ha scritto:
>
>> Dear Saha,
>>
>>this question has been asked many times in this forum so far (so 
>> many that it could deserve to be included in the FAQ, perhaps), so 
>> that you may get your reply by simply browsing in the forum archives. 
>> Very briefly, the code needs to know which electron manyfold of the 
>> "Hubbard" atomic species should be treated with the +U correction and 
>> what is the occupation of that electronic shell in the atom. This 
>> information has been already hardcoded for the most common elements. 
>> Evidently, Eu is not among those. You have to manually modify files 
>> set_hubbard_l.f90 and tabd.f90 (in the PW folder) according to what 
>> you think reasonable for your case.
>>
>>
>> Regards,
>>
>> GS
>>
>> Il giorno 13/lug/2010, alle ore 01.04, S. K. S. ha scritto:
>>
>>>  
>>>
>>> Dear QE Users,
>>>
>>> I got the following error while used GGA+U for EuO:
>>>
>>>  
>>> %%
>>>  from set_hubbard_l : error # 1
>>>  pseudopotential not yet inserted
>>>  
>>> %%
>>>
>>>  stopping ...
>>>
>>> Inside source file, I have found that "Eu" is mentioned. However, I 
>>> do not understand
>>> the meaning of inserting a pseudopotential.
>>>
>>> Thanks in advance for a helpful explanation. 
>>>
>>> With best regards,
>>>
>>> Saha SK
>>> R&D Assistant
>>> JNCASR
>>> Bangalore 560012
>>>
>>> ___
>>> Pw_forum mailing list
>>> Pw_forum at pwscf.org 
>>> http://www.democritos.it/mailman/listinfo/pw_forum
>>
>>
>> ? Gabriele Sclauzero, EPFL SB ITP CSEA
>> /   PH H2 462, Station 3, CH-1015 Lausanne/
>>
>> ___
>> Pw_forum mailing list
>> Pw_forum at pwscf.org 
>> http://www.democritos.it/mailman/listinfo/pw_forum
>
>
> ? Gabriele Sclauzero, EPFL SB ITP CSEA
> /   PH H2 462, Station 3, CH-1015 Lausanne/
>
> 
>
> ___
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>   

[Pw_forum] GGA+U

[S. K. S.]

Dear QE Users,

I got the following error while used GGA+U for EuO:

 %%
 from set_hubbard_l : error # 1
 pseudopotential not yet inserted
 %%

 stopping ...

Inside source file, I have found that "Eu" is mentioned. However, I do not
understand
the meaning of inserting a pseudopotential.

Thanks in advance for a helpful explanation.

With best regards,

Saha SK
R&D Assistant
JNCASR
Bangalore 560012
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[Pw_forum] GGA+U

[ali kazempour]

Dear all