[Pw_forum] Lowdin Charges

[Sakhrawi Taoufek]

thank you very much


________________________________
 De : Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
À : PWSCF Forum <pw_forum at pwscf.org> 
Envoyé le : Mercredi 5 juin 2013 16h42
Objet : Re: [Pw_forum] Lowdin Charges
 



Dear Sakhrawi Taoufek
I'm not sure I have understood... Yes, Bader  (or "Natural") charges are (best) calculated on the all electron density, and Lowdin charges are 
calculated in a different way and on the valence charge density only. They are also projected on atomic orbitals (more precisely, on angular momentum 
channels which are present in the corresponding pseudopotentials). Both can be used to study charge transfer effects. For example, you may calculate 
Lowdin charges for an isolated molecule and for a molecule interacting with a metal surface, and you may compare the values. By using the Lowdin 
charges you will obtain small differences between the values, which generally correspond to the correct trends of charge transfer, but are only 
qualitative estimates of what is happening to your interacting molecule.
HTH
Giuseppe

On Tuesday 04 June 2013 20:08:54 Sakhrawi Taoufek wrote:
> i ama asking about charge transfer analysis, Lowdin charge take in acount
> the population in orbital (if i am wrong correct me) and they are only
> valence electrons, compared with Bader analysis in wich we can analyse all
> electron (core and valence) and we can say that there ischarge transfer
> from metal to the substrate or vice versa, is it the same with Lowdin
> charge when we calculate the total electronic population in the fre metal
> and the total electronic population in the surface.
> 
> 
> ________________________________
>  De : Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
> À : PWSCF Forum <pw_forum at pwscf.org>
> Envoyé le : Mardi 4 juin 2013 18h31
> Objet : Re: [Pw_forum] Lowdin Charges
> 
> > i mean the unit of total charge,
> 
> They are valence electrons, of course; what else...? They are 
> partitioned in agreement with the Lowdin method, and are generally 
> neither integer values, nor too meaningful (in terms of physical 
> insight) values. Nevertheless, you may trust in trends: you change 
> something and see how the Lowdin partition reacts to such changes...
> 
> HTH
> 
> Giuseppe
> 
> Quoting Sakhrawi Taoufek <tsakhrawi at yahoo.com>:
> > i am sorry, i mean the unit of total charge, i am traying to do 
> > charge transfer with lowdin charge diference  in the interface 
> > metal/oxyde.
> > i run projwfc.x for free metal and projwfc.x for the interface then 
> > the difference in the total charge.
> > 
> > 
> > 
> > ________________________________
> >
> >  De : Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
> >
> > À : PWSCF Forum <pw_forum at pwscf.org>
> > Envoyé le : Mardi 4 juin 2013 13h55
> > Objet : Re: [Pw_forum] Lowdin Charges
> > 
> > 
> > 
> > Dear Sakhraoui Taoufik
> > 
> > And... what are you asking...? :-)
> > 
> > Giuseppe
> > 
> > 
> > Giuseppe mattioli
> > ISM-CNR
> > Italy
> > 
> > Quoting Sakhrawi Taoufek <tsakhrawi at yahoo.com>:
> >> Dear all,
> >> 
> >> it seems naaive but i am really asking about Lowdin charge 
> >> calculated with pdos.
> >> =======================================================
> >> 
> >> Lowdin Charges:
> >> 
> >>      Atom #   1: total charge =   7.2206, s =  0.4905, p =  0.0000, 
> >> d =  6.7302,
> >>                  spin up      =   5.1646, s =  0.2575, p =  0.0000, 
> >> d =  4.9072,
> >>                  spin down    =   2.0560, s =  0.2330, p =  0.0000, 
> >> d =  1.8230,
> >>                  polarization =   3.1086, s =  0.0245, p =  0.0000, 
> >> d =  3.0841,
> >> 
> >> =======================================================
> >> thanks
> >> ====================
> >> Sakhraoui Taoufik
> >> Phd student, LMCN
> >> Monastir,
> >>   Tunisia
> >> ====================
> > 
> > --
> > ********************************************************
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> >     Giuseppe Mattioli
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********************************************************
- 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)          
   Tel + 39 06 90672836 - Fax +39 06 90672316    
   E-mail: <giuseppe.mattioli at ism.cnr.it>
   ResearcherID: F-6308-2012

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