The ABINIT Users Mailing List ( CLOSED )

["Nuno A. G. Bandeira" <nuno.bandeira@ist.utl.pt>]

tfl03@mails.tsinghua.edu.cn wrote:
> Can Abinit investigate the valence state of the complex oxides?
>
> Dear everyone:
>         I want to use Abinit code to investigate a question of valence with 
> the real physical background. It is well known that the valence states of La, 
> Mn are 3+ in LaMnO3. When a Ca cation is substituted for La, Ca is 2+ and a 
> Mn3+ ion near the Ca ion changes into Mn4+. However, after imaging the charge 
> density given by Abinit, I find that there is no significant difference 
> between the charge density of Mn ions near the Ca ions and that of the Mn 
> ions near La ions.
>         The input file is enclosed as below and Troullier-Martins 
> pseudopotentials are used. The lattice parameters and the coordinates of ions 
> came from atomic simulation method, which are in agreement with some 
> experimental data approximately. Then, my questions are: i) Can Abinit code 
> investigate such complex compound as manganite? ii) Can Abinit code 
> investigate the valence state of elements in oxides? iii) Is there something 
> wrong in my input file? or I used the wrong pseudopotentials? Any help or 
> comment is welcomed.
>         Thank you very much!

You could try to do an AIM population analysis and get some charges from 
it.

Or if you want a more chemical viewpoint I'd recommend NWChem or 
Gaussian03. They provide a Mulliken and ELF analysis. Gaussian can also 
give you the Mayer-Mulliken bond orders for the oxides.

 The downside is it does not use space symmetry so it can take a while 
before you reach convergence.


--
Nuno A. G. Bandeira, AMRSC
Graduate researcher and molecular sculptor
Inorganic and Theoretical Chemistry Group,
Faculty of Science
University of Lisbon - C8 building, Campo Grande,
1749-016 Lisbon,Portugal
http://cqb.fc.ul.pt/intheochem/nuno.html
Doctoral student @ IST,Lisbon
--


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