The ABINIT Users Mailing List ( CLOSED )

[Masayoshi Mikami <mmikami@rc.m-kagaku.co.jp>]

Hello,

I would like to ask some questions, based on the FAQ:
http://www.abinit.org/ABINIT/Infos/FAQ.html#Difference

1) The FULL input would be more helpful to grasp what you did.
     (to avoid guessing what you did)
2) Which kind of pseudopotentials were adopted ?
    I mean, the pseudopotentials were taken from the ABINIT WEB site ?
    They were produced by a PP-making code (e.g. FHI98PP, OPIUM, ...) ?
    If so, which electron configurations were adopted for the PP-making  
?
   (which states were treated as core, which states as valence ?)
    It might be a good chance to read some documents such as
    ~ABINIT/Infos/Psp_infos/psp1.data . Literature survey may also  
help...
3) In general, oxygen pseudopotential need high energy cut, such as  
60-70 Ry
    for Troullier-Matins type. (the ecut will depend on the cut-off  
radii.)
    So, 30Ry-ecut results may deviate from plausible physical values.
4) How about simpler ** binary ** compounds to check the  
pseudopotentiasl ?
    For example, Y2O3, V2O5 ? (here, it might be better to keep the  
charge states
    of Y (3+) and V(5+)...)  Unfortunately, they might not be easy to  
calculate
    due to the size of the unit-cell... The primitive cell of Y2O3  
needs 40 atoms;
    the conventional cell has 80 atoms !)
    I guess V-potential might be more difficult to treat than  
Y-potential,
    so V2O5 might be a good case to check the transferability of  
V-potential ...

Best wishes,
Masayoshi

On 2004/03/19, at 3:21, Aldo Humberto Romero wrote:

> Dear Ab init users,
>
> I have been trying to do a calculation for YVO4 (with a cell very
> similar to the Zircon structure, just published in PRB vol 63, 104305)
> but using LDA and TM pseudo I am getting an error on the lattice  
> parametrs
> of almost 6%, which of course is unaceptable. I have changed the cutoff
> (from
> 30Ry to 60Ry) and the situation get worst.. K point is not an issue
> (I have used a Monkhorst-Pack mesh of 4x4x4  and 5x5x5 and the  
> diffference
> is less than 1 meV in the total energy...
>
> Any avice? something I should be aware of with respect to this
> system?.
>
> Thanks in advance!
>
> -aldo.
>
>
> ----------------------------------------------------------------------- 
> --
> Prof. Aldo Humberto Romero      
> IPICyT
> Advanced Materials Department
> Av. Venustiano Carranza 2425-A,
> 78270 San Luis Potosi, SLP, Mexico
>
> email:  aldo@ipicyt.edu.mx
> Phone:  (52)-444-8-33-54-11
> Fax:    (52)-444-8-33-54-12
> http://www.ipicyt.edu.mx/