[Pw_forum] Pseudopotential problem about Mg

[Stefano Baroni]

On Mar 2, 2007, at 6:09 AM, Axel Kohlmeyer wrote:

> On Fri, 2 Mar 2007, Lawrence Lee wrote:
>
> LL> Dear all,
> LL>
>
>
> LL> I did a molecular dynamics run using pw.x on MgO, using
> LL> pseudopotentials generated myself. The results turn out to be  
> quite
> LL> different from literature. I suspect that it's my  
> pseudopotential's
> LL> problem. Here below is the input file for ld1.x. Since I am  
> green in
> LL> generating pseudopotential, can anyone point out any problems  
> in my
> LL> input file, if there are any?
>
> Mg is a tough customer in terms of pseudopotentials.
> i've been trying to get a good Mg potential on and off
> for quite a while now. so it is probably better you start
> with practicing on some easier elements.
>
> also, for MgO you'll need to include semi-core states.
> a minimal pseudo will essentially be stripped off almost
> all its electron density and is likely to give bad results.

or include non-linear core corrections at the very least (semi-core  
states may require a very large cutoff for norm-conserving PP's or  
multiple projectors for US PP's)

S.

---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
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