[Pw_forum] pseudopotential

Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu
Mon Feb 11 20:23:51 CET 2008

On Mon, 11 Feb 2008, saman ghaderyan wrote:

SG> thanks dear Axel for quickly answer (like always)
SG> where can I found that pseudopotentials?

please check the literature. a quick search gives, 
e.g., Crocombette et al., Phys.Rev.B 64 (2002), 104107

SG>  and I think for study phonon structure NC-pp are better because we use B-O
SG> approximation and studied core region with NC-pp are good results,
SG> and for exchange correlation energy for heavy atoms, LDA are better because
SG> the effective of core on valance region is weak and the orbitals are close
SG> recovery in valance region,
SG> is these true?

i cannot comment on this.

SG> and when l localized f in valance region then I  have to  use  US-pp and I
SG> think the result for phonon structure are not true but the result for
SG> electronic structure (lattice parameter) are true !

with d-, and even more so f-electrons DFT is always hit-or-miss.
getting the right lattice parameter can just be an accident.
i had this happen to me on other elements.


Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
   Center for Molecular Modeling   --   University of Pennsylvania
Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323
tel: 1-215-898-1582,  fax: 1-215-573-6233,  office-tel: 1-215-898-5425
If you make something idiot-proof, the universe creates a better idiot.

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