The ABINIT Users Mailing List ( CLOSED )

[marc.torrent@cea.fr]

Hi,

This message is just an "informative" message ;
If PAW atomic data were perfect, then Vloc(R)=-Zv/R above a given radius R.
In "real computations" this is of course not the case...
but lower is the difference between Vloc and Z/R better is the result.

A good (empirical) precision is 10-7 or 10-8... but 10-6 is not too bad...

If you want to get better accuracy, two solutions:
1-simple but perhaps not possible: increase sphere radius (only if your 
system allows it : spheres cannot overlap).
2-more complex: modify in the source code the radius above which Vloc is 
taken as -Zv/r ; this parammeter is set by vloc_meshsz_max in subroutine 
calc_vhnzc. You can increase this value but NOT TOO : this can increase 
dramatically CPU time in Abinit.

An advice : leave your data unchanged (or increase vloc_meshsz_max just a 
little)...



Marc Torrent



Note: what we call Vloc here actually is: Vhartree(nval(r)+ncore(r))



-----------------------------------------------------------------
# From: "Amancherla, Sundar (CORP, GEITC)" <Sundar.Amancherla@geind.ge.com>

I am trying to use atompaw to get a paw potential for Y. Prof Holzwarth was
kind enough to send me an input file for Y. The rc used is 3.0. I am getting
these messages after running atompaw2abinit -

--------------
Info:
Max. value of mesh size for Vloc=Vhnzc(r) has been reached.
Vhnzc( 3000)= -Z/r+ -7.320E-06
Precision of Vloc in Abinit's psp file will be poor.
Possible action: increase sphere radius.
--------------

Pls do let me know any comments / suggestions that you may have. Thanks very
much
--
Aman