[Pw_forum] U for Oxygen
ali kazempour
kazempoor2000 at yahoo.com
Tue Aug 4 10:07:44 CEST 2009
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 . 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?
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> wrote:
From: Matteo Cococcioni <matteo at umn.edu>
Subject: Re: [Pw_forum] occupation
To: "PWSCF Forum" <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
ali kazempour wrote:
> Dear Matteo
> I follow your link and is useful for me, but when I want to study a
> nonmagnetic material like Tio2 ,how do I change the format of
> pos_file.? for NiO it is in tutorial ,but NiO is antiferromagnetic and
> in pos_nio.r16 you add a switch 1,-1 and 0 in front of atomic type.
> but for TiO2, it is nonmagnetic. How can I define the differnet type?
> 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 *Thu, 7/30/09, Matteo Cococcioni /<matteo at umn.edu>/* wrote:
>
>
> From: Matteo Cococcioni <matteo at umn.edu>
> Subject: Re: [Pw_forum] occupation
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Date: Thursday, July 30, 2009, 11:18 AM
>
>
> the new tutorial on the calculation of U can be downloaded from this
> webpage:
>
> http://www.quantum-espresso.org/wiki/index.php/QESB09#First_week
>
>
> Matteo Cococcioni wrote:
> > Dear Ali,
> >
> > on the wiki page of quantum-espresso you should be able to find
> a new
> > tutorial on the calculation of U. Please download it
> > and run the scripts in there following the instructions.
> >
> >
> >
> > ali kazempour wrote:
> >
> >> Dear all
> >>
> >> From Linear response calculation ,I get for TiO2 bulk U=5.73,
> But when
> >> I double the unit cell in z direction and again compute U ,I
> get three
> >> different value for Ti atoms.(U=5.63,5.46,5.70).
> >>
> >>
> >
> > what are these three values? I assume they are what you get with
> > supercells of three different sizes. is this correct? if it is
> the only
> > strange thing is that the intermediate value is lower than the
> other
> > two. otherwise you got pretty nice convergence of U which is
> what you
> > want to achieve. Is there any particular reason (apart
> computational
> > cost) why you only enlarge the cell in z direction?
> >
> >
> >> Why these values are not same . what is the main reason? Does
> it in
> >> numerical variation errors?
> >> ANother question:
> >> When we perturb D level by alpha, it give rise to change in d
> >> occupancy . Is it correct that if we impose negative alpha , the
> >> occupation becomes less than initial state .?
> >>
> >>
> >
> > no. positive alpha -- > decrease in total n. but you need to
> look at the
> > right n....
> >
> >
> >> for Ti isolated atom for apha=0.1 tr[ns(na)] after
> first-iteration
> >> equal to the 0.002 and at the end of calculation is 2.327 while we
> >> know that for Ti, tr[ns(na)] =2.000. Does it seems to be correct.?
> >>
> >> Number of iteration with fixed ns = 0
> >> Starting ns and Hubbard U :
> >> enter write_ns
> >> U( 1) = 0.0000
> >> alpha( 1) = 0.1000
> >> atom 1 Tr[ns(na)]= 2.0000000
> >> atom 1 spin 1
> >> eigenvalues: 0.4000000 0.4000000 0.4000000 0.4000000 0.4000000
> >> eigenvectors
> >> 1 1.0000000 0.0000000 0.0000000 0.0000000 0.0000000
> >> 2 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000
> >> 3 0.0000000 0.0000000 1.0000000 0.0000000 0.0000000
> >> 4 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000
> >> 5 0.0000000 0.0000000 0.0000000 0.0000000 1.0000000
> >> occupations
> >> 0.400 0.000 0.000 0.000 0.000
> >> 0.000 0.400 0.000 0.000 0.000
> >> 0.000 0.000 0.400 0.000 0.000
> >> 0.000 0.000 0.000 0.400 0.000
> >> 0.000 0.000 0.000 0.000 0.400
> >> atom 1 spin 2
> >> eigenvalues: 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000
> >> eigenvectors
> >> 1 1.0000000 0.0000000 0.0000000 0.0000000 0.0000000
> >> 2 0.0000000 1.0000000 0.0000000 0.0000000 0.0000000
> >> 3 0.0000000 0.0000000 1.0000000 0.0000000 0.0000000
> >> 4 0.0000000 0.0000000 0.0000000 1.0000000 0.0000000
> >> 5 0.0000000 0.0000000 0.0000000 0.0000000 1.0000000
> >> occupations
> >> 0.000 0.000 0.000 0.000 0.000
> >> 0.000 0.000 0.000 0.000 0.000
> >> 0.000 0.000 0.000 0.000 0.000
> >> 0.000 0.000 0.000 0.000 0.000
> >> 0.000 0.000 0.000 0.000 0.000
> >> nsum = 2.0000000
> >> exit write_ns
> >>
> >>
> >
> > this is not the first iteration. this is what the initial guess
> of the
> > on-site occupations the code does to start the calculation
> >
> >
> >
> >> Atomic wfc used for LDA+U Projector are NOT orthogonalized
> >> Starting wfc are 9 atomic + 1 random wfc
> >>
> >> total cpu time spent up to now is 13.34 secs
> >>
> >> per-process dynamical memory: 326.3 Mb
> >>
> >> Self-consistent Calculation
> >>
> >> iteration # 1 ecut= 45.00 Ry beta=0.70
> >> CG style diagonalization
> >> c_bands: 3 eigenvalues not converged
> >> c_bands: 2 eigenvalues not converged
> >> ethr = 1.00E-12, avg # of iterations = 40.4
> >> enter write_ns
> >> U( 1) = 0.0000
> >> alpha( 1) = 0.1000
> >> atom 1 Tr[ns(na)]= 0.0021401
> >> atom 1 spin 1
> >> eigenvalues: 0.0000001 0.0000001 0.0000001 0.0009883 0.0009883
> >> eigenvectors
> >> 1 0.0000000 -0.8803392 -0.4743427 0.0000000 0.0013927
> >> 2 0.0000000 -0.4743432 0.8803400 0.0000000 -0.0000040
> >> 3 0.0000000 0.0012242 0.0006642 0.0000000 0.9999990
> >> 4 -0.8886820 0.0000000 0.0000000 -0.4585240 0.0000000
> >> 5 0.4585240 0.0000000 0.0000000 -0.8886820 0.0000000
> >> occupations
> >> 0.001 0.000 0.000 0.000 0.000
> >> 0.000 0.000 0.000 0.000 0.000
> >> 0.000 0.000 0.000 0.000 0.000
> >> 0.000 0.000 0.000 0.001 0.000
> >> 0.000 0.000 0.000 0.000 0.000
> >>
> >>
> >
> > this is the first iteration! the problem is, in my opinion, that
> you
> > didn't start this calculation from wfc and potential saved from
> the scf
> > unperturbed run, but from scratch (that's why the code has to
> make the
> > initial guess for the n).
> >
> > regards,
> >
> > Matteo
> >
> >> ---------------------------------- and end of the file is
> >> :
> >> End of self-consistent calculation
> >> enter write_ns
> >> U( 1) = 0.0000
> >> alpha( 1) = 0.1000
> >> atom 1 Tr[ns(na)]= 2.3270531
> >> atom 1 spin 1
> >> eigenvalues: 0.1574294 0.1574294 0.1574294 0.9273825 0.9273825
> >> eigenvectors
> >> 1 0.0000000 -0.4359030 -0.7986559 0.0000000 0.4148945
> >> 2 0.0000000 0.7269732 -0.0406891 0.0000000 0.6854592
> >> 3 0.0000000 -0.5305643 0.6004109 0.0000000 0.5983379
> >> 4 -0.9258933 0.0000000 0.0000000 -0.3777851 0.0000000
> >> 5 0.3777851 0.0000000 0.0000000 -0.9258933 0.0000000
> >> occupations
> >> 0.927 0.000 0.000 0.000 0.000
> >> 0.000 0.157 0.000 0.000 0.000
> >> 0.000 0.000 0.157 0.000 0.000
> >> 0.000 0.000 0.000 0.927 0.000
> >> 0.000 0.000 0.000 0.000 0.157
> >>
> >>
> >> 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
> >>
> >>
> >>
> ------------------------------------------------------------------------
> >>
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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
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
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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
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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