[Pw_forum] Why the calculated equilibrium lattice parameters

[Paolo Giannozzi]

On Nov 15, 2007, at 3:26 , 岩 李 wrote:

> The  Cs pseudopotential on pwscf.org considers only one electron.
> But  more  electrons should be considered as valence electrons if
> I want study the characters of Cs under very high pressure.
> Therefore, I considered the configurations 5s2 5p6 6s1 for Cs.

my first first-principle calculation was about phase transitions in
CsI under pressure (PRB 35, 765 (1987)) : see the "Notes on
Pseudopotential Generation" in atomic_doc/pseudo-gen.pdf .
We used a 9-electron PP (in semilocal form, so unsuitable
for today's usage). Most likely, if you get bad results, your
pseudopotential has a ghost, as explained in the above
mentioned "Notes", or you haven't followed the correct
procedure in generating it.

I have four 9-e PP's on my disk, generated in 2005.
They are PBE and PZ (Perdew-Zunger LDA), 5s2 5p6 6s0
and 5s2 5p6 6s1, L=0 is the local part for all of them.
I don't remember why they are there and whether they
work or not. They come with some atomic tests, plus
tests for metallic Cs that somebody did somewhere,
whose results I ignore. Here they are:
http://www.fisica.uniud.it/~giannozz/public/Cs.tar.gz
No warranty. If some of them seem to work, please
report (nobody does it, but I keep asking)

Paolo
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Paolo Giannozzi, Dept of Physics, University of Udine
via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222