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["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi,

What you are saying appears quite weird without having a look at your input file. Would you mind telling us a little bit more (for instance showing abinit's input and output) ?
By the way, if the SCF convergence of your system is really as difficult as you describe it I'm very much interested in having a look at it. I would be very grateful if you share with me pseudopotentials and input file.

Regards

PMA

On 6/5/07, zaq Liu <iloveabinit@gmail.com> wrote:

Dear Dr. Marc Torrent,

Thank you very much for your suggestion.
I find that rc=3.2 seems to be reasonable for hcp Gd metal.
3.2 is a little smaller than the half of the distance for two Gd ions (3.37).
The relaxed lattice constant is very close to the exp. values (smaller by 2%)
But during the calculation,the SCF loops need about 200-300 times.
Furthermore, when I calculate GdN and GdP, the SCF loops never reach
convergence after 350 times. I try a number of variables diemac dielng
and iprcel and iscf 14, 17 , but the situation does not change.
Could you please give me some useful advice how to improve the atomic
data for Gd?
Thank you very much!

Best regards,

Bo Liu

2007/6/1, Marc Torrent <marc.torrent@cea.fr >:
> Quick answer, with some key ideas:
>
> - you should verify your log derivatives and eventually change the
> reference energy (especially for d, f electrons).
> - your high cut-off is a sign of a small pseudization radius ; are you
> sure of the rc=2. or 2.2 ? I think you should obtain reasonnable values
> for ecut with rc=2.4.
>
> Marc Torrent
>
>
> iloveabinit@gmail.com a écrit :
> > Dear All,
> >
> > I generate the Gd atomicdata using atompaw code.
> > The calculated lattice constants  of hcp Gd and GdN show
> > a very large errors (smaller than the experimental values by about 15%).
> > The LDA and GGA show the similar results. Also the ecut needed is about 28 Ha when the total energy difference is smaller than 1meV/atom. Is this ecut too high ? I know the common ecut for PAW is about 15 Ha.
> >
> > The input file is attached below. The attached file uses rc=2.0, I also test rc=2.2 and get the same result. I am appreciated for any useful advice!
> >
> > Bo Liu
> >
> > INPUTFILE
> >
> > Gd 64  #1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 (5s2 5p6 4f7 5d1 6s2)
> > LDA-PW scalarrelativistic loggrid 2001
> > 6 5 5 4 0
> > 4 3 7
> > 5 2 1
> > 0 0 0
> > c
> > c
> > c
> > c
> > v
> > v
> > c
> > c
> > c
> > v
> > c
> > c
> > v
> > v
> > 3
> > 2.0 2.0 2.0 2.0   #rc rpaw
> > n
> > y
> > 2
> > n
> > y
> > 3
> > n
> > y
> > 5
> > n
> > Vanderbilt
> > 4 0
> > 2.0
> > 2.0
> > 2.0
> > 2.0
> > 2.0
> > 2.0
> > 2.0
> > 2.0
> > 0
> >
> >
> >
> >
>

-- 
Pierre-Matthieu Anglade