[Pw_forum] pseudo potential generation problem

Paolo Giannozzi giannozz at democritos.it
Mon Dec 15 15:35:52 CET 2008

yumin qian wrote:

>      from run_pseudo : error #         1
>      Errors in PS-KS equation
> I don't know  what cause this error.

nor do I, but what I know for sure that it is quite difficult
to get a pseudopotential right even with reasonable generation
parameters. With unreasonable parameters like these:

> 5P  2  1  0.00  0.00  2.20  3.40  0.00
> 5S  1  0  2.00  0.50  2.10  2.60  0.00

it is close to impossible.
[ Rc=2.10 and 2.20 are unreasonably small for orbitals whose maximum
  is located at 3.6690 and 4.8303 a.u. respectively; 2.60 and 3.40 are
  for UltraSoft pseudization and are ignored with option iswitch=2,
  i.e. Norm Conserving pseudization with multiple projectors per
  angular momentum; in this case equivalent to iswitch=1, since there
  is just one projector per angular momentum above.]
In general, it is close to impossible to produce a pseudopotential
without some understanding of how the generation procedure works,
and some care in preparing input data (for which a rather detailed
documentation exists)

Paolo Giannozzi, Democritos and University of Udine, Italy

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