[Pw_forum] [Re:] ld1.x problem (not really)
calderin at physics.queensu.ca
Sat Jan 26 22:20:31 CET 2008
> 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 the
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.
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?)).
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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