Re: [Pw_forum] Alignment of total energy?

[Giuseppe Mattioli]

Dear Ari
If you have a charged slab and/or a strong dipole along z, the esm pbc in a 
vacuum-slab-vacuum (i.e. esm='bc1') fashion might help a lot to have a flat 
asymptotic value of the potential outside the slab. Moreover, pw.x 
automatically calculates the z average of V_xc and v_H and store them into a 
prefix.esm1 file.
Best
Giuseppe

On Monday, February 27, 2017 10:05:12 PM Nicola Marzari wrote:
> Hi Ari,
> 
> 
> yes, you can plot Vhartree or Vhartree_xc as they flattens out in the
> vacuum -
> first should be shorter ranged (see Caspar Fall PhD thesis).
> 
> If you have a slab geometry, you can do a planar average in the directions
> parallel to the slab.
> 
> Indeed, make sure it is flat - trickier if you have a charged system (for
> a charged slab, it's a simple correction - see Dabo prb 2008).
> 
>   nicola
> 
> On 27/02/2017 13:00, Ari P Seitsonen wrote:
> > Dear Colleagues,
> > 
> >   I tried to search the FAQ and archives but was not successful - sorry
> > 
> > if this is already answered somewhere.
> > 
> >   I am trying to calculate core level binding energies of atoms, and for
> > 
> > this I need to align the total energies of the two calculations, with
> > and without the core hole; the calculations are on surfaces/slabs, so I
> > could use either the Fermi energies or the value of (dipole-corrected)
> > potential in the vacuum. But I have forgotten which term is needed
> > still... (Sorry, it is some 25 years when I was doing similar things.)
> > Was it something like the average potential in the cell times some
> > factor...?
> > 
> >   Thank you in advance for any answer. :)
> >   
> > Greetings from Paris,
> > 
> >apsi
> > 
> > -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
> > 
> >   Ari Paavo Seitsonen / ari.p.seitso...@iki.fi / http://www.iki.fi/~apsi/
> >   
> > Ecole Normale Supérieure (ENS), Département de Chimie, Paris
> > Mobile (F) : +33 789 37 24 25(CH) : +41 79 71 90 935
> > 
> > ___
> > Pw_forum mailing list
> > Pw_forum@pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum


- 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

___
Pw_forum mailing list
Pw_forum@pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum

Re: [Pw_forum] Alignment of total energy?

[Nicola Marzari]

Hi Ari,


yes, you can plot Vhartree or Vhartree_xc as they flattens out in the 
vacuum -
first should be shorter ranged (see Caspar Fall PhD thesis).

If you have a slab geometry, you can do a planar average in the directions
parallel to the slab.

Indeed, make sure it is flat - trickier if you have a charged system (for
a charged slab, it's a simple correction - see Dabo prb 2008).

nicola



On 27/02/2017 13:00, Ari P Seitsonen wrote:





>
> Dear Colleagues,
>
>   I tried to search the FAQ and archives but was not successful - sorry
> if this is already answered somewhere.
>
>   I am trying to calculate core level binding energies of atoms, and for
> this I need to align the total energies of the two calculations, with
> and without the core hole; the calculations are on surfaces/slabs, so I
> could use either the Fermi energies or the value of (dipole-corrected)
> potential in the vacuum. But I have forgotten which term is needed
> still... (Sorry, it is some 25 years when I was doing similar things.)
> Was it something like the average potential in the cell times some
> factor...?
>
>   Thank you in advance for any answer. :)
>
> Greetings from Paris,
>
>apsi
>
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
>
>   Ari Paavo Seitsonen / ari.p.seitso...@iki.fi / http://www.iki.fi/~apsi/
> Ecole Normale Supérieure (ENS), Département de Chimie, Paris
> Mobile (F) : +33 789 37 24 25(CH) : +41 79 71 90 935
>
>
> ___
> Pw_forum mailing list
> Pw_forum@pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>

-- 
--
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project
___
Pw_forum mailing list
Pw_forum@pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum

[Pw_forum] Alignment of total energy?

[Ari P Seitsonen]

Dear Colleagues,

  I tried to search the FAQ and archives but was not successful - sorry if 
this is already answered somewhere.


  I am trying to calculate core level binding energies of atoms, and for 
this I need to align the total energies of the two calculations, with and 
without the core hole; the calculations are on surfaces/slabs, so I could 
use either the Fermi energies or the value of (dipole-corrected) potential 
in the vacuum. But I have forgotten which term is needed still... (Sorry, 
it is some 25 years when I was doing similar things.) Was it something 
like the average potential in the cell times some factor...?


  Thank you in advance for any answer. :)

Greetings from Paris,

   apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
  Ari Paavo Seitsonen / ari.p.seitso...@iki.fi / http://www.iki.fi/~apsi/
Ecole Normale Supérieure (ENS), Département de Chimie, Paris
Mobile (F) : +33 789 37 24 25(CH) : +41 79 71 90 935___
Pw_forum mailing list
Pw_forum@pwscf.org
http://pwscf.org/mailman/listinfo/pw_forum