[Pw_forum] scf for BaTiO3

[Axel Kohlmeyer]

>>> "WY" == WANG Yuan Xu <wang.yuanxu at nims.go.jp> writes:

WY> Dear all,
WY>         When I calculate BaTiO3.
WY> I use the Ba pseudo file from PWscf web site.  And O an Ti was Ti.vdb.UPF and O.vdb.UPF

WY> I get the error information "from readpp # 2  inconsistent DFT read"

WY> The three atoms must all same GGA or LDA? If it is true. The website
WY> only give Ba GGA no Ba LDA. How should I do.

hi,

you are correct, your pseudopotentials have to be created 
with consistent functionals (not only all GGA by itself, but
also the same GGA, with LDA the differences are smaller) 
pwscf reads the functional to be used for the calculation
from the pseudopotential.

to get a consistent set, you have to recreate them using
a consistent DFT.

in case of vanderbilt USPPs you have to download the uspp
pp code from the vanderbilt uspp homepage:
http://www.physics.rutgers.edu/~dhv/uspp/
compile it and follow the instructions to generate
the potentials. if you need a different DFT you
can usually change the pseudopotential generation
parameter file (XXX_ps.adat). from my experience,
this works well, if you want to switch between
different GGA DFTs; switching from LDA to GGA
has not worked very well.

the resulting .uspp files can then be transformed
to UPF format with the uspp2upf.x utility. some
uspp files use the full element name instead of
the atomic symbol, you'll have to change that manually
with a text editor, after you have converted your 
pseudopotentials to upf. you should also mention,
how you have created the UPF file in the <PP_INFO> section,
especially if you have changed the DFT from the 
original settings.

regards,
     axel kohlmeyer

WY> Best


WY> WANG Yuan Xu
WY> National Institute for Materials Science
WY> Computational Materials Science Center
WY> Namiki 1-1, Tsukuba 305-0044, Japan
WY> Phone +81-29-8513354-8092; Fax +81-29-8541207
WY> wang.yuanxu at nims.go.jp
WY> 2004-09-30

WY> _______________________________________________
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WY> Pw_forum at pwscf.org
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--

=======================================================================
Axel Kohlmeyer       e-mail: axel.kohlmeyer at theochem.ruhr-uni-bochum.de
Lehrstuhl fuer Theoretische Chemie          Phone: ++49 (0)234/32-26673
Ruhr-Universitaet Bochum - NC 03/53         Fax:   ++49 (0)234/32-14045
D-44780 Bochum  http://www.theochem.ruhr-uni-bochum.de/~axel.kohlmeyer/
=======================================================================
If you make something idiot-proof, the universe creates a better idiot.