[Pw_forum] about epsilon

[degironc]

Dear Amin,
     using US PP would be preferable but if this is not possible one 
option is to use a Zn pseudopotential that bury the 3d orbital in the 
core. You NEED THEN to use non-linear core correction in the 
pseudopotential otherwise very poor results are obtained but with NLCC 
some decent description comes out for semiconductors [see for instance  
Ferroelectrics 111, 19 (1990);  Phys. Rev. B 47, 3588 (1993),   Phys. 
Rev. Lett. 80,  4939 (1998), Appl. Phys. Lett.  75, 2746 (1999) ].
     Unfortunately I don't have at hand any of the Zn pseudopotentials 
used in those works... I ll' try to dig in my archives but you may also 
try to generate one using ld1.x code (maybe modifying the input for As 
or the one for Al that are included in atomoc_doc/pseudo-gen/  ... )
     stefano

Amin Babazadeh wrote:

> Dear Andrea
> Thanks a lot for your clear answer.
> I have another question.do you have a any idea for solving my problem 
> i will appreciate if you give me some idea.
> can i find pseudopotential from other cods like abinit?I didn't work 
> with abinit or it's pseudopotentail  but i see in the espresso's 
> mailing list that some people use the abinit pseudopotentail.
> thanks a lot
>
> On 12/14/06, *Andrea Ferretti* <ferretti.andrea at unimore.it 
> <mailto:ferretti.andrea at unimore.it>> wrote:
>
>
>
>     >
>     >
>     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>     >     from epsilon : error #         1
>     >     USPP are not implemented
>     >
>     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
>     >
>     >
>     > i think this error says that the epsilon.x doesn't  work on US
>     > pseudopotential
>
>     this is exactly the point, you are right...
>
>     > ------
>     > IF ( okvan ) CALL errore('epsilon','USPP are not implemented',1)
>     > ------
>     > i don't know what okvan is?is this mean a spatial kind of USPP i
>     should use
>     > or it said that i can't use US pseudopotential.
>
>     okwan is a logical variable which is .TRUE. if at least one of the
>     pseudopotentials in the calculation is ultrasoft (or vanderbilt
>     type)...
>
>
>     > I also want to test it with non conserving potential bur
>     unfortunately  i
>     > couldn't find any pseudopotential for ZnS.
>
>     unfortunately, while S does not need USPP, Zn is it quite hard in
>     terms of
>     cutoff energy, and therefore, after a brief check, it seems the
>     pseudopage
>     of espresso does not contain any norm-conserving pseudo for Zn.
>
>     andrea
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>
>
>
> -- 
> AMIN