The ABINIT Users Mailing List ( CLOSED )

[Martin Fuchs <fuchs@fhi-berlin.mpg.de>]

Hi,

the abinit pseudopotential is likely meant for nonmagnetic
(spin-unpolarized) calculations. To make it work for spin
polarized cases, one has to include a partial core density
to take into account the nonlinear core-valence xc, similar
in LSDA and GGA. Without them, pseudpotential calculations
energetically favor more spin-polarized over less spin-
polarized/unpolarized states. Possibly, this is the reason
why your V goes magnetic (although it should not, and does
not (?) in an all-electron calculation).

A test of the V pseudopotential/abinit is to do an unpolarized
calculation of bcc V. Using the fhi code I once got the
PW91-GGA (similar to PBE) lattice constant=3.04 Ang which
is very reasonable.

Pseudopotentials with partical cores may be generated
using the fhipp program, see abinit web site.

On the role of the partical core to magnetic and other
cases, see  e.g. S.G. Louie PRB 26 1783.

Martin


amall ramanathan wrote:

> Hi Everybody,
> There is something seriously wrong with the 23.V.GGA.fhi 
> pseudopotential for the element Vanadium. When I did a spin polarised 
> calculation for bulk Vanadium, with a ecut of 40 Ha, and grid 8 8 8, I 
> get a large magnetic moment of 1.76 Bohr magneton. Bulk Vanadium is 
> definitely not magnetic and it is supposed to have zero spin. I tried 
> with different lattice constants from 5.6 to 5.8 Bohr and it always 
> gave the same large value.
> I am desperately in need of a dependable GGA pseudopotential for 
> Vanadium that I could use in Abinit. I would be very grateful to 
> anybody who can send me one.
> Thanks,
> Amall.
>
> Cheap Talk? Check out 
> <http://us.rd.yahoo.com/mail_us/taglines/postman8/*http://us.rd.yahoo.com/evt=39663/*http://voice.yahoo.com> 
> Yahoo! Messenger's low PC-to-Phone call rates. 


--
Martin Fuchs
Phone:  +30 8413 4802           | Fritz-Haber-Institut der MPG
Fax:    +30 8413 4701           | Faradayweg 4-6
E-Mail: fuchs@fhi-berlin.mpg.de | D-14195 Berlin (Germany)

1-0.0735-11600-23.05