[Pw_forum] U for Oxygen

[Matteo Cococcioni]

Dear Ali,

this is a file where we collected the results from the calculation of U.

first column is the number of atom in the supercell, second column is 
the U of Ni third column the U of O.

Matteo

ali kazempour wrote:
> Dear Matteo
> Thanks for your help. In attachment there is outout file for U for NiO 
> that I get from wiki.This file has three column.
> thanks
>
> Ali Kazempour
> Physics de *8/4/09, Matteo Cococcioni /<matteo at umn.edu>/* wrote:
>
>
>     From: Matteo Cococcioni <matteo at umn.edu>
>     Subject: Re: [Pw_forum] U for Oxygen
>     To: "PWSCF Forum" <pw_forum at pwscf.org>
>     Date: Tuesday, August 4, 2009, 6:59 AM
>
>
>
>     Dear Ali,
>
>
>
>     ali kazempour wrote:
>     > Dear Matteo
>     > I used your comment and followed   your example for NiO and I
>     succeed 
>     > to get U for TiO2. But in file Ur16.out I see three column .
>     >
>
>     I don't have any three column section in any of my files. so if
>     you want
>     me to help you you have to report at least a section of your output
>     file. This is a good habit actually in consideration of the fact that
>     this is not a private conversation (I would have asked you in any
>     case
>     as I don't remember by heart the format of any file) between me
>     and you
>     but a message to the forum and you want other people to understand
>     what you are saying.
>
>     > The first is number of atom in supercell , second is U value for Ni
>     > atom and I don,t know  the third? does the third belong to  U value
>     > for Oxygen or not? Because the third column kas big value?
>     >
>     >
>     > another question is for isolated atom Hubbard parameter. What do
>     you
>     > expect about the value of U for Isolated atom? Is this big value
>     > (greater than 10 eV) or  it would be tiny value?
>     >
>
>     I think it will be meaningless for the reasons I explained in my last
>     email. To obtain a meaningful number for the isolated atom you
>     probably
>     have to abandon the idea to use a perturbation in the potential and
>     change instead the number of electrons directly. This means you will
>     have to do calculations on atoms having fractional charges which
>     requires additional corrections if you use a code designed for
>     periodic
>     systems (crystals). However I have never done this isolated atom
>     calculation of U before so I don't have more details about it.
>     I see (from a private email) you are thinking of computing U for the
>     isolated atom and to obtain a value for the crystal just by
>     dividing by
>     the epsilon_inft. the method is proposed in
>
>     http://link.aps.org/doi/10.1103/PhysRevB.74.045202
>
>     (which I haven't re-read yet).
>
>     I see a couple of problems:
>
>     1) (not important for ZnO). suppose you have Fe3O4 with Fe2+ and
>     Fe3+.
>     these Fe ions likely have different U. how do you obtain
>     a different number from the atomic code? would you do the calculation
>     for isolated Fe2+ and Fe3+?
>
>     2) how do you get epsilon? since it's a linear response property I
>     don't
>     think its calculation is any cheaper than the direct calculation of U.
>
>     regards,
>
>     Matteo
>
>     > should we choose for running the script for isolated atom only
>     gamma
>     > point or we have to choose a fine mesh?
>     > thanks a lot
>     >
>     >
>     > Ali Kazempour
>     > Physics department, Isfahan University of Technology
>     > 84156 Isfahan, Iran. Tel-1: +98 311 391 3733
>     > Fax: +98 311 391 2376 Tel-2: +98 311 391 2375
>     >
>     > --- On *Sun, 8/2/09, Matteo Cococcioni /<matteo at umn.edu
>     </mc/compose?to=matteo at umn.edu>>/* wrote:
>     >
>     >
>     >     From: Matteo Cococcioni <matteo at umn.edu
>     </mc/compose?to=matteo at umn.edu>>
>     >     Subject: Re: [Pw_forum] occupation
>     >     To: "PWSCF Forum" <pw_forum at pwscf.org
>     </mc/compose?to=pw_forum at pwscf.org>>
>     >     Date: Sunday, August 2, 2009, 8:31 AM
>     >
>     >
>     >     Dear Ali,
>     >
>     >     1, -1, 0 are just spin indexes to tell the code what is the
>     relative
>     >     magnetization of the atoms (parallel, antiparallel, or none). if
>     >     your system is non magnetic put all 0. or set magn = .false.
>     and put
>     >     nothing.
>     >     you should look at the examples on Fe and Si as well and
>     learn from
>     >     there by comparison.
>     >
>     >     Matteo
>     >
>     >
>     >
>
>
>     -- 
>     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>     Matteo Cococcioni
>     Department of Chemical Engineering and Materials Science,
>     University of Minnesota
>     421 Washington Av. SE
>     Minneapolis, MN 55455
>     Tel. +1 612 624 9056    Fax +1 612 626 7246
>     %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
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-- 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Matteo Cococcioni
Department of Chemical Engineering and Materials Science,
University of Minnesota
421 Washington Av. SE
Minneapolis, MN 55455
Tel. +1 612 624 9056    Fax +1 612 626 7246
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%