[Pw_forum] R: Fermi energy

[DELLACA' Valentina (CRF)]

Dear Giuseppe,
I've read the papers you suggested, and indeed they helped a lot. Now I have a 
further question regarding the Delta V: since we are working with high defect 
concentrations, the cell parameters change going from the non defective bulk to 
the defective cells. With VESTA I can plot  the  potential in a 2D plane 
obtained by slicing  the cell. How can I evaluate the potential at the same 
point in the defective and non defective cell, considering that the cell 
parameters are different? Is there a trick I can use?
Thank you very much for your help,
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT ? Materials CAE Development & Virtual Analysis 

?
Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel? +39 011 9083138
Fax +39 011 9083666

www.crf.it 

-Messaggio originale-
Da: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] Per 
conto di Giuseppe Mattioli
Inviato: mercoled? 28 maggio 2014 12:07
A: pw_forum at pwscf.org
Oggetto: Re: [Pw_forum] Fermi energy


Dear Valentina

> Is it already the Fermi Energy defined in the article by Zunger?

Definitely not! You should individuate the valence band maximum and use the 
corresponding eigenvalue in the formula as a constant. The Fermi level is the 
variable (you calculate the formation energy at a given Fermi level, and, 
possibly, the transition level between two different charge states of the same 
defect). The rationale is that the position of transition levels should be 
independent on the Fermi level. I may suggest (but do not tell prof. Zunger, 
please...) that Van de Walle's paper is somewhat clearer:

Van de Walle, C. G.; Neugebauer, J.; J. Appl. Phys. 2004, 95, 3851.

A very recent review by Pacchioni and Di Valentin, which improves in some 
details the calculation of transition levels, can be found here:

http://pubs.acs.org/doi/pdf/10.1021/ar4002944

There is also another detail, often hidden into the papers. When you perform 
the calculations in a plane-wave/pseudopotential PBC framework, if you change 
the total charge, you also insert a background charge that shift the potential 
(defined up to a constant
value) and, in turn, the eigenvalues. You should insert some DeltaV value in 
the formation energy formula to recover the shift. If the supercell is large, 
and the dielectric constant of the host matrix is high (let us say a >100-atom 
cell of TiO2, for instance), then DeltaV is negligibly small. Otherwise you can 
find something around some tenths of eV. However, Pacchioni and Di Valentin 
have tested a workaround for the estimate of DeltaV (see the review).

> occupations='smearing' with degauss =1d-20

I hope that it is degauss =1d-2

HTH

Giuseppe

Giuseppe Mattioli
ISM-CNR
Italy

Quoting "DELLACA' Valentina (CRF)" :

> Hi,
> We are computing the formation energies of charged defects in 
> supercells. We are referring to Lany and Zunger, Phys. Rev. B 78,
> 235104 (2008) Eq. (1).
> The Fermi energy used here is defined as  Ev (valence band maximun)
> + delta E Fermi ; i.e. is defined with respect the valence band
> maximum.
> The system we are working with is an insulator, and we are using 
> occupations='smearing' with degauss =1d-20 in order to have the Fermi 
> Energy written in the log file.( Please, tell me if we are doing 
> something wrong here!) The question is: the Fermi Energy that I read 
> in the log file, is defined respect to what? Is it already the Fermi 
> Energy defined in the article by Zunger?
> Thanks,
> Regards
> Valentina
>
>
> Valentina Dellac?
> Group Materials Labs
> PA&CT - Materials CAE Development & Virtual Analysis
>
>
> Centro Ricerche Fiat S.C.p.A.
> Sede legale e amministrativa: Strada Torino, 50
> 10043 Orbassano (TO), Italia
> Tel  +39 011 9083138
> Fax +39 011 9083666
>
> www.crf.it<http://www.crf.it>


--

- Article premier - Les hommes naissent et demeurent libres et ?gaux en droits. 
Les distinctions sociales ne peuvent ?tre fond?es que sur l'utilit? commune
- Article 2 - Le but de toute association politique est la conservation des 
droits naturels et imprescriptibles de l'homme. Ces droits sont la libert?, la 
propri?t?, la s?ret? et la r?sistance ? l'oppression.


Giuseppe Mattioli
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
v. Salaria Km 29,300 - C.P. 10
I 00015 - Monterotondo Stazione (RM)
Tel + 39 06 90672836 - Fax +39 06 90672316
E-mail: 

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[Pw_forum] R: Fermi energy

[DELLACA' Valentina (CRF)]

Dear Giuseppe,
Thanks a lot. Indeed it was a 1d-2.
I am going to read the articles you suggested.
Best regards,
Valentina 

Valentina Dellac?
Group Materials Labs
PA&CT ? Materials CAE Development & Virtual Analysis 

?
Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel? +39 011 9083138
Fax +39 011 9083666

www.crf.it 


-Messaggio originale-
Da: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] Per 
conto di Giuseppe Mattioli
Inviato: mercoled? 28 maggio 2014 12:07
A: pw_forum at pwscf.org
Oggetto: Re: [Pw_forum] Fermi energy


Dear Valentina

> Is it already the Fermi Energy defined in the article by Zunger?

Definitely not! You should individuate the valence band maximum and use the 
corresponding eigenvalue in the formula as a constant. The Fermi level is the 
variable (you calculate the formation energy at a given Fermi level, and, 
possibly, the transition level between two different charge states of the same 
defect). The rationale is that the position of transition levels should be 
independent on the Fermi level. I may suggest (but do not tell prof. Zunger, 
please...) that Van de Walle's paper is somewhat clearer:

Van de Walle, C. G.; Neugebauer, J.; J. Appl. Phys. 2004, 95, 3851.

A very recent review by Pacchioni and Di Valentin, which improves in some 
details the calculation of transition levels, can be found here:

http://pubs.acs.org/doi/pdf/10.1021/ar4002944

There is also another detail, often hidden into the papers. When you perform 
the calculations in a plane-wave/pseudopotential PBC framework, if you change 
the total charge, you also insert a background charge that shift the potential 
(defined up to a constant
value) and, in turn, the eigenvalues. You should insert some DeltaV value in 
the formation energy formula to recover the shift. If the supercell is large, 
and the dielectric constant of the host matrix is high (let us say a >100-atom 
cell of TiO2, for instance), then DeltaV is negligibly small. Otherwise you can 
find something around some tenths of eV. However, Pacchioni and Di Valentin 
have tested a workaround for the estimate of DeltaV (see the review).

> occupations='smearing' with degauss =1d-20

I hope that it is degauss =1d-2

HTH

Giuseppe

Giuseppe Mattioli
ISM-CNR
Italy

Quoting "DELLACA' Valentina (CRF)" :

> Hi,
> We are computing the formation energies of charged defects in 
> supercells. We are referring to Lany and Zunger, Phys. Rev. B 78,
> 235104 (2008) Eq. (1).
> The Fermi energy used here is defined as  Ev (valence band maximun)
> + delta E Fermi ; i.e. is defined with respect the valence band
> maximum.
> The system we are working with is an insulator, and we are using 
> occupations='smearing' with degauss =1d-20 in order to have the Fermi 
> Energy written in the log file.( Please, tell me if we are doing 
> something wrong here!) The question is: the Fermi Energy that I read 
> in the log file, is defined respect to what? Is it already the Fermi 
> Energy defined in the article by Zunger?
> Thanks,
> Regards
> Valentina
>
>
> Valentina Dellac?
> Group Materials Labs
> PA&CT - Materials CAE Development & Virtual Analysis
>
>
> Centro Ricerche Fiat S.C.p.A.
> Sede legale e amministrativa: Strada Torino, 50
> 10043 Orbassano (TO), Italia
> Tel  +39 011 9083138
> Fax +39 011 9083666
>
> www.crf.it<http://www.crf.it>


--

- Article premier - Les hommes naissent et demeurent libres et ?gaux en droits. 
Les distinctions sociales ne peuvent ?tre fond?es que sur l'utilit? commune
- Article 2 - Le but de toute association politique est la conservation des 
droits naturels et imprescriptibles de l'homme. Ces droits sont la libert?, la 
propri?t?, la s?ret? et la r?sistance ? l'oppression.


Giuseppe Mattioli
CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
v. Salaria Km 29,300 - C.P. 10
I 00015 - Monterotondo Stazione (RM)
Tel + 39 06 90672836 - Fax +39 06 90672316
E-mail: 

___
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Pw_forum at pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum

[Pw_forum] Fermi energy

[DELLACA' Valentina (CRF)]

Hi,
We are computing the formation energies of charged defects in supercells. We 
are referring to Lany and Zunger, Phys. Rev. B 78, 235104 (2008) Eq. (1).
The Fermi energy used here is defined as  Ev (valence band maximun) + delta E 
Fermi ; i.e. is defined with respect the valence band maximum.
The system we are working with is an insulator, and we are using 
occupations='smearing' with degauss =1d-20 in order to have the Fermi Energy 
written in the log file.( Please, tell me if we are doing something wrong here!)
The question is: the Fermi Energy that I read in the log file, is defined 
respect to what? Is it already the Fermi Energy defined in the article by 
Zunger?
Thanks,
Regards
Valentina


Valentina Dellac?
Group Materials Labs
PA&CT - Materials CAE Development & Virtual Analysis


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it

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[Pw_forum] R: electrostatic potential

[DELLACA' Valentina (CRF)]

Thnak you for your answers.
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT ? Materials CAE Development & Virtual Analysis 

?
Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel? +39 011 9083138
Fax +39 011 9083666

www.crf.it 


-Messaggio originale-
Da: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] Per 
conto di Paolo Giannozzi
Inviato: sabato 22 marzo 2014 09:55
A: PWSCF Forum
Oggetto: Re: [Pw_forum] electrostatic potential

On Fri, 2014-03-21 at 22:19 +0530, Sridhar Sadasivam wrote:

> I think V_bare means the potential due to the nuclei

more exacty: the local part of the pseudopotential, without the nonlocal part

> and V_hartree is the potential due to electrons

the electrostatic potential of the charge density, as usually defined

> The units of the potential are in Ry.

"potentials" are actually multiplied by e, so they are "potential energies"

Paolo

> Sridhar
> Purdue University
> 
> 
> On Fri, Mar 21, 2014 at 10:00 PM, DELLACA' Valentina (CRF) 
>  wrote:
> Dear all,
> 
> In my understanding, to plot the electrostatic potential of a
> crystal one needs to perform a post processing run with pp.x,
> with plot_num=11. I was wondering the exact meaning of the
>  V_bare  and  V_H potential, and in which units the results
> come out.
> 
> Thanks a lot!
> 
> Valentina
> 
>  
> 
> Valentina Dellac?
> Group Materials Labs
> PA&CT ? Materials CAE Development & Virtual Analysis
> 
> 
>  
> Centro Ricerche Fiat S.C.p.A.
> Sede legale e amministrativa: Strada Torino, 50
> 10043 Orbassano (TO), Italia
> Tel  +39 011 9083138
> Fax +39 011 9083666
> 
> www.crf.it
> 
>  
> 
> 
> 
> ___
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> http://pwscf.org/mailman/listinfo/pw_forum
> 
> 
> ___
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--
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, Univ. Udine, via delle 
Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222 

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[Pw_forum] electrostatic potential

[DELLACA' Valentina (CRF)]

Dear all,
In my understanding, to plot the electrostatic potential of a crystal one needs 
to perform a post processing run with pp.x, with plot_num=11. I was wondering 
the exact meaning of the  V_bare  and  V_H potential, and in which units the 
results come out.
Thanks a lot!
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT - Materials CAE Development & Virtual Analysis


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it

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[Pw_forum] R: hybrid calculation with dexx negative

[DELLACA' Valentina (CRF)]

Hi,
Thank you for the suggestion. I will try to go from gygi_baldereschi to vcut_ws 
as exxdiv_treatment.
Regards,
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it<http://www.crf.it>

Da: pw_forum-bounces at pwscf.org [mailto:pw_forum-bounces at pwscf.org] Per 
conto di mohnish pandey
Inviato: gioved? 30 gennaio 2014 11:16
A: PWSCF Forum
Oggetto: Re: [Pw_forum] hybrid calculation with dexx negative

Hi Valentina,

May be it will help: 
http://qe-forge.org/pipermail/pw_forum/2013-November/102690.html

On Thu, Jan 30, 2014 at 10:52 AM, DELLACA' Valentina (CRF) mailto:valentina.dellaca at crf.it>> wrote:
Dear all,
We are performing surface calculations with hybrid functional, and for the 
following surface structure at the moment the error saying: 'dexx is negative, 
error # 1 , check that exxdiv_treatment is appropriate for the system' is 
giving us some troubles. We already tried to change the distance between 
surfaces, changing celldm(3), around its optimized value 2.39, we changed also 
mixing_beta to 0.3, and we tried with few different k point grids. None of this 
attempt was successful in solving the error. We also changed the occupations to 
smearing, and we gave a small degauss (1d-20), but then (with many celldm(3)) 
it was not even converging the first scf.
Any suggestion on how to fix this error?
Thank you,
Regards,
Valentina

&CONTROL
  calculation = 'scf',
 restart_mode = 'from_scratch',
   outdir = '',
  pseudo_dir  = '',
  prefix = 'ta2o5' ,
  disk_io = 'default',
/
  &SYSTEM
ibrav = 8,
celldm(1) =  14.241893092,
celldm(2) =  0.822831603,
celldm(3) =  2.39,
  nat = 38,
 ntyp = 2,
   ecutwfc=70, nbnd=700, occupations='fixed',
 input_dft = 'PBE0',
exxdiv_treatment = 'gygi-baldereschi'
x_gamma_extrapolation=.true.
nqx1 = 1 , nqx2 = 1, nqx3 = 1
/
&electrons
conv_thr=1.0d-9, mixing_beta=0.5
/
ATOMIC_SPECIES
Ta   180.95  Ta.pbe-mt-fhi.UPF
O   15.999   O.pbe-mt-fhi.UPF



ATOMIC_POSITIONS (angstrom)
O0.813278477   4.617988459   8.007774872
O2.023476210   0.776972843   8.441046448
Ta   1.546871435   2.767467670   7.799599600
O3.366054079   3.877523758   8.440539307
Ta   3.843027211   5.867856582   7.799473875
O5.792152399   5.359043398   8.438587876
Ta   5.314346183   3.366897623   7.799507537
O4.577766398   1.516932685   8.008262086
O7.134074123   2.258690100   8.438344309
Ta   7.612245398   0.266340494   7.800172819
O3.496914324   5.857316984   5.883545751
O5.660946844   3.375012981   5.883534436
O1.890303432   2.756178342   5.883603671
O7.271488124   0.274248516   5.883520878
O5.637305636   5.330921586   3.862497327
O3.523414777   3.905957403   3.865060769
O0.813798912   4.618557268   3.867613313
O1.868771197   0.805909423   3.864412229
O4.578829938   1.517577526   3.866842485
O7.290961638   2.230024951   3.864847639
O3.497903745   5.858106076   1.841803379
O1.888736406   2.757775274   1.841813170
O5.659923444   3.372905841   1.841275566
O7.273010266   0.273369852   1.841504469
O5.792500075   5.359007930  -0.713580871
O3.366000630   3.876131545  -0.715282591
O0.813543928   4.618155682  -0.280250553
O2.025151305   0.776423231  -0.714789822
O4.578389288   1.516157053  -0.281620473
O7.134187444   2.259560146  -0.714019402
Ta   3.631274701   5.991239815   3.862567887
Ta   1.760248756   2.890622602   3.862584360
Ta   5.528096689   3.245167855   3.862383012
Ta   7.400881489   0.144629430   3.862458735
Ta   7.613260471   0.266812681  -0.075602588
Ta   5.314089138   3.366439123  -0.075243654
Ta   3.843827877   5.867144678  -0.074583652
Ta   1.546399836   2.767291744  -0.074953513



K_POINTS {automatic}
2 2 1  0 0 0

Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it<http://www.crf.it>


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Regards,
MOHNISH,
--

[Pw_forum] hybrid calculation with dexx negative

[DELLACA' Valentina (CRF)]

Dear all,
We are performing surface calculations with hybrid functional, and for the 
following surface structure at the moment the error saying: 'dexx is negative, 
error # 1 , check that exxdiv_treatment is appropriate for the system' is 
giving us some troubles. We already tried to change the distance between 
surfaces, changing celldm(3), around its optimized value 2.39, we changed also 
mixing_beta to 0.3, and we tried with few different k point grids. None of this 
attempt was successful in solving the error. We also changed the occupations to 
smearing, and we gave a small degauss (1d-20), but then (with many celldm(3)) 
it was not even converging the first scf.
Any suggestion on how to fix this error?
Thank you,
Regards,
Valentina

&CONTROL
  calculation = 'scf',
 restart_mode = 'from_scratch',
   outdir = '',
  pseudo_dir  = '',
  prefix = 'ta2o5' ,
  disk_io = 'default',
/
  &SYSTEM
ibrav = 8,
celldm(1) =  14.241893092,
celldm(2) =  0.822831603,
celldm(3) =  2.39,
  nat = 38,
 ntyp = 2,
   ecutwfc=70, nbnd=700, occupations='fixed',
 input_dft = 'PBE0',
exxdiv_treatment = 'gygi-baldereschi'
x_gamma_extrapolation=.true.
nqx1 = 1 , nqx2 = 1, nqx3 = 1
/
&electrons
conv_thr=1.0d-9, mixing_beta=0.5
/
ATOMIC_SPECIES
Ta   180.95  Ta.pbe-mt-fhi.UPF
O   15.999   O.pbe-mt-fhi.UPF



ATOMIC_POSITIONS (angstrom)
O0.813278477   4.617988459   8.007774872
O2.023476210   0.776972843   8.441046448
Ta   1.546871435   2.767467670   7.799599600
O3.366054079   3.877523758   8.440539307
Ta   3.843027211   5.867856582   7.799473875
O5.792152399   5.359043398   8.438587876
Ta   5.314346183   3.366897623   7.799507537
O4.577766398   1.516932685   8.008262086
O7.134074123   2.258690100   8.438344309
Ta   7.612245398   0.266340494   7.800172819
O3.496914324   5.857316984   5.883545751
O5.660946844   3.375012981   5.883534436
O1.890303432   2.756178342   5.883603671
O7.271488124   0.274248516   5.883520878
O5.637305636   5.330921586   3.862497327
O3.523414777   3.905957403   3.865060769
O0.813798912   4.618557268   3.867613313
O1.868771197   0.805909423   3.864412229
O4.578829938   1.517577526   3.866842485
O7.290961638   2.230024951   3.864847639
O3.497903745   5.858106076   1.841803379
O1.888736406   2.757775274   1.841813170
O5.659923444   3.372905841   1.841275566
O7.273010266   0.273369852   1.841504469
O5.792500075   5.359007930  -0.713580871
O3.366000630   3.876131545  -0.715282591
O0.813543928   4.618155682  -0.280250553
O2.025151305   0.776423231  -0.714789822
O4.578389288   1.516157053  -0.281620473
O7.134187444   2.259560146  -0.714019402
Ta   3.631274701   5.991239815   3.862567887
Ta   1.760248756   2.890622602   3.862584360
Ta   5.528096689   3.245167855   3.862383012
Ta   7.400881489   0.144629430   3.862458735
Ta   7.613260471   0.266812681  -0.075602588
Ta   5.314089138   3.366439123  -0.075243654
Ta   3.843827877   5.867144678  -0.074583652
Ta   1.546399836   2.767291744  -0.074953513



K_POINTS {automatic}
2 2 1  0 0 0

Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it

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[Pw_forum] R: Re: vdW+PBE0

[DELLACA' Valentina (CRF)]

Thanks a lot for your answer,
Best regards,
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it




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[Pw_forum] vdW+PBE0

[DELLACA' Valentina (CRF)]

Dear Paolo,
Thank you very much for your answer.
Best regards
Valentina


Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it<http://www.crf.it>

Da: DELLACA' Valentina (CRF)
Inviato: venerd? 13 dicembre 2013 09:36
A: 'giuseppe.mattioli at ism.cnr.it'; 'pw_forum at pwscf.org'
Cc: SGROI Mauro Francesco (CRF)
Oggetto: Re: vdW+PBE0

Dear Giuseppe,
Thank you very much for your answer.
Best regards
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it<http://www.crf.it>

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[Pw_forum] vdW+PBE0

[DELLACA' Valentina (CRF)]

Dear Giuseppe,
Thank you very much for your answer.
Best regards
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it

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[Pw_forum] vdW+PBE0

[DELLACA' Valentina (CRF)]

Dear Quantum Espresso users,
We are modeling a system which needs the hybrid functional approach to be 
correctly simulated. Next, we need to compute the Oxygen chemical potential, 
and it has to be compared with the energy of the system. It is a fact that van 
der Waals interactions are not negligible when modeling molecular Oxygen.  In 
order to have comparable quantities, we are wondering if it is possible to use 
in Quantum Espresso a mixture of van der Waals and PBE0 to model the Oxygen 
molecule.
Thanks,
Valentina


Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it

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[Pw_forum] problems with charged systems + hybrid functionals

[DELLACA' Valentina (CRF)]

Hi,
I am simulating a system which requires the hybrid functional approach in order 
to reproduce experimental data. If the system is neutral, everything works 
fine, but when we introduce a tot_charge of -2 something goes wrong. The 
computation goes on, with scf, exx, and after some cycles the dexx is negative, 
so it gives me an error message and the computation stops. As I understood, 
there are numerical problems and a possible cause is that the exx divergence 
treatment has failed. I was wondering whether with the presence of the charge I 
should change something more than the divergence treatment in the input file, 
or if you have some ideas in how to proceed.
Thanks a lot for the attention,
Best regards
Valentina

Valentina Dellac?
Group Materials Labs
PA&CT - Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it

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[Pw_forum] R: restart with hybrid functionals

[DELLACA' Valentina (CRF)]

Hi, 
thank you very much for the answer.
Valentina

_
Valentina Dellac?
Group Materials Labs
PA&CT ? Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it


Da: pw_forum-bounces at pwscf.org [pw_forum-bounces at pwscf.org] per conto di 
Paolo Giannozzi [paolo.giannozzi at uniud.it]
Inviato: luned? 29 aprile 2013 21.49
A: PWSCF Forum
Oggetto: Re: [Pw_forum] restart with hybrid functionals

On Mon, 2013-04-29 at 18:31 +0200, DELLACA' Valentina (CRF) wrote:

> is it possible to restart a run when it is already computing the EXX term?

the development (svn) version should restart properly (no warranty),
WITHOUT the need for "disk_io='high'", ONLY if the code is stopped
via a "prefix".EXIT file or using the variable "max_seconds"

P.

--
Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222

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[Pw_forum] restart with hybrid functionals

[DELLACA' Valentina (CRF)]

Hi,
I am working with hybrid functionals, and since the time demand for these runs 
is quiet large, we are using a server with many CPUs. My question is : is it 
possible to restart a run when it is already computing the EXX term?
Thank you!
Valentina




_
Valentina Dellac?
Group Materials Labs
PA&CT ? Virtual Analysis & Materials Modelling


Centro Ricerche Fiat S.C.p.A.
Sede legale e amministrativa: Strada Torino, 50
10043 Orbassano (TO), Italia
Tel  +39 011 9083138
Fax +39 011 9083666

www.crf.it