[Pw_forum] Praseodymium Pseudopotential(s)

[Stefano de Gironcoli]

Dear Paul,
   I have no experience with Praseodymium but have been involved in some 
calculations with Cerium that shares with it the mixed valence nature.
   Stefano Fabris (here in cc) generated a couple of pseudopotentials 
that were successfully used in a number of studies. He can send you  
more info... and possibly post the pseudos on the web...
   Beware however that in order to obtain even qualitatively sensible 
results with Ce (and I guess also with Pr)  DFT+U or a similarly 
self-interaction corrected scheme is mandatory.
   best regards,
          Stefano de Gironcoli 


w2agz wrote:
> Ciao Tutti (especially Paolo, Mateo etc.),
>
>  
>
> OK, I've been away for a while, busy with energy issues and trying to understand why Alex Mueller may have been on the right track wrt to explaining why high temperature superconductivity manifests in the copper oxide perovskites.  PW_FORUM is not the right place to "advertize" one's publications, but I owe much to the QE community and its creators and contributors.  Contact me if you're interested in further info.
>
>  
>
> The reason for this posting is as follows:
>
> (1)    I'd like to investigate via QE-DFT the "properties" of several Pr, alkaline earth-oxide perovskites, and thus need to have an appropiate Pr pseudopotential, one that would be compatible with the PP library of QE.
>
> (2)    Browsing the QE, Vanderbilt, Opium, Haber and Martins sites (US-PS, NC-PS), I could find "none" that were pregenerated.
>
> (3)    Therefore, I may be "on my own," and would appreciate advice:
>
> a.       Is the community aware of any suitable Pr PPs I could obtain and use?
>
> b.      If not, I'd appreciate advice on how to generate my own, using either the "famous" ld1.x,  or a suitable equivalent
>
> c.   Does anyone know about or use the "Octopus" site (http://www.tddft.org/programs/octopus)
>
> (4)    Pr is a particular pernicious element ([Xe] 4f3-6s2) .  Simply put, it can be either 3+ or 4+.or somewhere in between - the 4f states are known to hybidize extensively.  Studies I did at IBM on the Pr-1237 system indicated its ground quantum state may be in some sort of "heavy fermion" configuration.  Think about it.  Why is not Pr-1237 superconducting.or even metallic, even though its crystal structure is nearly identical to Y-1237?  That's the most unsolved mystery of 20th century condensed matter physics.next to why the copper oxide perovskites are superconducting at all.
>
>  
>
> Finally, I remind all of the wisdom of David Vanderbilt's remark, something to the effect, "Pseudopotential generation is a black art."
>
>  
>
> Paolo, can you work your magic?
>
>  
>
> Ciao, -Paul
>
>   
> ------------------------------------------------------------------------
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>