[gpaw-users] Severe convergence problems

[Marcin Dulak]

Hi,

On 08/19/2014 12:22 PM, Michael Busch wrote:
> Hi all,
>
> I am currently studying the activity of different doped MnO2 slabs. 
> All systems are based on a MnO2 structure  and contain Ta + a 
> transition metal as dopants. The structures where taken from previous 
> calculations so the starting guesses should be reasonable. While most 
> systems converge without significant problems I am having severe 
> convergence problems for several of the Ni doped oxides. All 
> calculations are spin polarised with the spin being allowed to change 
> during the calculations. The obtained spins seem to be reasonable for 
> the system at hand. A summary of the used parameters can be found below.
>
> Until now I tried the following to achieve convergence:
>
> - different eigensolvers: cg and Davidson
> - gradually increasing smearing from 0.1 eV to values as high as 1.5 
> eV (!)
> - modifying the mixing parameters between 0.001 and 0.1
>
>
> Is there any possibility to obtain convergence that I did not consider 
> until now?
please provide the script.
Magnetic systems are tricky.

Best regards,

Marcin

>
> All the best
>
> Michael
>
>
>
> calc = GPAW(
>             xc='RPBE',
>              h=0.15,
>         charge=0,
>        spinpol=True,
>      occupations=FermiDirac(
>                 width=1.0,
>             fixmagmom=False
>                          ),
>           kpts=(2, 1, 1),
>      convergence={'energy': 0.0005},
>        maxiter=1024,
>      eigensolver='cg',
>        usesymm=True,
>  mixer=Mixer(0.05, 5, weight=100.0),
>            )
>