[Wien] Slab convergence

[Lukasz Plucinski]

  Hello,

I am trying to calculate 1ML of Fe on top of Au(001).

It was no problem to calculate 20ML slab of Au(001), it converged after 
37 iterations with mixing 0.1, 100k-points and all other standard 
settings, also using "spin-polarized" calculation mode. I use 50 A of 
the unit cell dimension, to have appropriate amount of vacuum.

However, when I put 1 Fe atom on top of one side of the slab the 
calculation didn't converge after 100 iterations (I did couple of 
trials). I also tried to increase the cutoff to -8 Ry, and the 
calculation is running now, however, no convergence indications after 35 
iterations.

My slab is not relaxed, and the distance between Fe and Au (3.295 au) is 
taken from the old publication of  Freeman JMMM 75, 201 (1988).

Automatic RMT distance procedure has put all RTM to 2.5, however, this 
way there is a lot of space between Au atoms. I think its better to use 
2.72 for Au atoms and 2.34 for Fe atom -- is there any problem with this 
? Neither setting helps the convergence...

Maybe I could decrease the amount of k-points to have faster iterations 
with even lower mixing parameter ?

Regards,
Lukasz