[Pw_forum] CuO, LDA+U, Pseudopots, etc.

[Henning Glawe]

On Wed, Dec 12, 2007 at 11:40:56PM -0800, Paul M. Grant wrote:
> Simplistically, the initial d-state configuration of Cu2+ in CuO by Hund’s
> Rule should be 3d9 (one empty minority spin state state
a hole).   But, with
> nspin=2, lda_plus_u set true, and U=5 eV (arbitrary), the initial minority
> spin occupation gets set to unity, not 4/5 on average (3/5 for Ni and 1/5
> for Fe).  Is this due to occ_loc being set to 10 in tabd.f90 and not 9 (it’s
> 6 for Fe and 8 for Ni)?  The occupation distribution converges to around

as the d shell can be filled with 10 electrons, getting a initial hole into the 
d shell while occ_loc=10 is IMHO impossible.


> functionals have equivalent occupations and give similar results).  When I
> try Cu.pz-d-rrkjus.UPF, with 3d10, 4s1 and 4p-1(!!!), the first scf
> iteration yields individual spin occupations of nearly 5(!!!), and the
> situation gets really ugly thereafter.

I also encountered this problem with this pseudo potential; the problem lies
in the normalization of the 3d wave functions saved in the pp file. if you
search in the archives of the pw forum, you will find a patch for pwscf
allowing to recalculate the norm of the atomic states after the pp file has
been read.

-- 
c u
henning