[Pw_forum] convergence problem in scf calculation in rare earth oxide Sm2O3

[Mohammed Khalafalla]

Dears Karim and Ari,
Thank you so much for your kind comments and suggestions.
Regards
Mohammed


On Mon, Nov 27, 2017 at 5:27 AM Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>
wrote:

>
> Dear Mohammed,
>
>    I do not not know anything about the compound, but one note: Did you
> notice that the keyword 'starting_magnetization' expects values between -1
> and 1, those limits meaning full spin polarisation of the valence
> electrons (or, a relative polarisation)? If this is not what you wanted,
> the guess (ferro-magnetic, apparently) for the initial density can be
> quite far from the final value. And indeed all the lanthanides are
> difficult to handle, I do not know how accurate the available PAW/pseudo
> potentials are; one might consider starting initially with a fixed
> total magnetisation to see if one can converge then. Yet in some cases I
> am still fighting to get the electronic structure to converge, even in
> molecules.
>
>    Sorry, I have no better suggestions.
>
>      Greetings,
>
>         apsi
>
>
> -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
>    Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi / http://www.iki.fi/~apsi/
>      Ecole Normale Supérieure (ENS), Département de Chimie, Paris
>      Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935
>
>
> On Sat, 25 Nov 2017, Mohammed Khalafalla wrote:
>
> > Dear all,
> > I could not achieve scf convergence in Sm2La2O6 (the input file is
> attached herewith). This was the case even after several 'restart' of the
> > calculation with different pseudpotentials specially for 'O' atom. I
> guess I used well tested PAW psedu for rare earth from
> > http://www.vlab.msi.umn.edu/resources/repaw/index.shtml
> > I used recommended hubbard potentials and spin polarization, but no
> change. Generally I found convergence in (Sm,O) system to be difficult. Can
> > you kindly let me know which parameter set-up would determine successful
> convergence in (Sm,O) system?
> > Regards,
> > Mohammed A. H. Khalafalla (PhD)
> > Taibah University
> > KSA
> >
> >
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