[Pw_forum] [Re:] ld1.x problem (not really)
calderin at physics.queensu.ca
Sun Jan 27 04:19:11 CET 2008
On Sat, 2008-01-26 at 22:20 +0100, Lazaro Calderin wrote:
> > that's the fault of the Ritz's variational principle, boys!
> Stefano .. yes, I agree .. but just in principle.
> In practice I have came across tested pseudopotentials that give
> good results for the solid, however, they have ghosts. I think I can
> give as examples the Pb, Tl and Bi pseudos in the uspp pseudopotentials
> library. There is a ghost that do not appear in the tests with bessel
> functions but if you go to deep enough in energy (down to -8 ry) in
> calculation of the log derivatives you should see it (I still should
> have those tests somewhere). So the program some how must be omitting
> that ghost probably because is out of the range of interest.
No .. I am definitely wrong .. I checked my notes and those are states
of the all electron hamiltonian. But je .. I still think I came across
that case ..
> Any ways, I think it is a very extended practice to keep an eye only on
> the range of energy of the solid when designing the psps. (If I remember
> well that is even a recommendation in some tutorials (uspp?)).
That is the case but it is dangerous practice.
Sorry for the monologue .. it's been a long coughing night, L.
Lazaro Calderin, Ph.D.
Dpt. of Theoretical, Atomic and Optical Physics
Univ. of Valladolid, 47005 Valladolid. Spain
Phone: +34 983 423891 Fax: +34 983 423013
E-mails: calderin at fta.uva.es or calderin at physics.queensu.ca
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