The ABINIT Users Mailing List ( CLOSED )

[Steven Homolya <Steven.Homolya@spme.monash.edu.au>]

On Tue, 21 Oct 2003 02:57 am, homegchiche@yahoo.fr wrote:
>  Dear Steven Homolya and all abinit users,
>
> Tahanks for your last answers and your help.
>
> this is my input file to one Vacancy in 2x2x2 fcc nickel :
>

>  my question is if this two intput files are compatible to calculate the
> formation energy ?.
>

I can see quite a few problems with your input files.

Most severe is your 'xcart's in the file for the 8 site supercell. I assume 
they were supposed to be 'xred's. Even then you have doubled up on some 
coordinates, e.g.
0.5 0.5 1.0
is the same as
0.5 0.5 0.0

There is also k-point number and ecut inconsistency between the two files. 
ngkpt 8 8 8 for one site fcc unit cell corresp. to ngkpt 4 4 4 for the 8-site 
fcc supercell. For ecut consistency, remember that it is scaled by 
dilatmax^2.

You should also relax the supercell (the lattice will distort around a 
vacancy 
after all), in which case you should use toldff (10 times smaller than 
toldmxf) as SCF stopping criterion. Use optcell=2, ionmov=3 (or prefarably do 
optcell=0 first and then optcell=2).

Cheers,

Steve

-- 
Steven Homolya
School of Physics and Materials Engineering
Monash University VIC 3800
Australia
Tel: INT +61 3 9905 3694
Fax: INT +61 3 9905 3637