The ABINIT Users Mailing List ( CLOSED )

[Matthieu Verstraete <mjv500@york.ac.uk>]

On the contrary! This is really a very good result for the 
pseudopotentials. The core corrections is obviously necessary in an 
element with high lying core states, but the results are as close as you 
can expect them in the pseudopotential approximation.

If you are concerned about the wiggles in the abinit DOS, they come from 
the kpoint sampling and the way the DOS is calculated. Use prtdos 2 to get 
a smoother results with the tetrahedron method (which is certainly what is 
used in wien).

Your last phrases were a bit worrying, it sounded like you were changing 
convergence parameters to get the DOS closer to the wien one. You must not 
do this! You should converge the kpoints, ecut, etc... until the results 
do not change anymore. They are not free parameters.

The psp core radii and NLCC parameters are a bit trickier, but normally 
fitting the psp for the free atom should be enough to give you a nice 
transferable potential (well, not always strictly true). As you can see, 
changing the NLCC parameter does change the DOS, but mainly in the 
unoccupied states. There is a general recipe for setting the rnlc to the 
radius at which the valence density becomes larger than the core density, 
but this is a bit arbitrary. In many cases, people do what you have done 
here, and use the rnlc which best reproduces an all electron calculation.

Matthieu

--
================================================================
Dr. Matthieu Verstraete                 mailto:mjv500@york.ac.uk
Dept. of Physics, University of York,     tel: +44 1904 43 22 08
Heslington, YO10 5DD York, United Kingdom fax: +44 1904 43 22 14