[Pw_forum] How to fixed the valence of atom

[奥野幸洋]

Dear PWSCF users.

I'm now try to fixed the valence of one atom in the cell.

For example, how we impose one of the Nb atom as (+4) valence

(one electron is localized in Nb atom   Nb(+5) is ideal condition )

in the crystal.

I tried to use  constrained_magnetization = 'atomic'

with statring_magnetization  like below,

(Here atom index 2 is Nb atom which I set as valence (+4, one electron

localized in Nb atom, 3 is Nb atom with ideal +5 valence )

   starting_magnetization(1) = 0.0
    starting_magnetization(2) = 1.0
    starting_magnetization(3) = 0.0
    starting_magnetization(4) = 0.0
    starting_magnetization(5) = 0.0
    lda_plus_u =.TRUE.
    lda_plus_u_kind = 0
    Hubbard_U(2)=4.0
    Hubbard_U(3)=4.0
    tot_charge = -1.0
    tot_magnetization = 1.0
    constrained_magnetization = 'atomic'
    lambda = 1.0

But, the results was some of Nb atoms has a little excess electron (,
but smaller than one ), and I couldn't get +4 Nb which I aimed to
make.

How to treat to impose the localized electron in one of the atoms

in crystals.

If I can get reply, I'm very happy.

Sincerely,

Yukihiro Okuno.

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