[Wien] lda+u calculation

[Yundi Quan]

Both cases are very converged. One gives magnetic solution. The other gives
non-magnetic solution. The magnetic solution is slightly lower in energy.




On Thu, Feb 16, 2012 at 4:48 PM, Laurence Marks <L-marks at northwestern.edu>wrote:

> Maybe, or maybe not! If both cases are well converged, that means that
> for your approximations there are two locally stable spin states.
> Maybe this is real, maybe not, that is hard to say.
>
> 2012/2/16 Yundi Quan <quan at ms.physics.ucdavis.edu>:
> > You are right. The spin state is different in two cases. Applying U
> after a
> > scf calculation seems to tend to reduce the magnetic moments.
> >
> >
> >
> >
> >
> >
> >
> >
> > On Thu, Feb 16, 2012 at 3:44 PM, Laurence Marks <
> L-marks at northwestern.edu>
> > wrote:
> >>
> >> If all other things are the same, the lowest energy is correct
> >> (variational principle). Probably the spin state is different in the
> >> two cases.
> >>
> >> But...please ensure that you really have both converged. Assuming that
> >> you have a recent version, do a "grep -e :MV case.scf" (with case
> >> replaced as appropriate). The % value should be small for true
> >> convergence; if it is not you do not have real convergence
> >> (technically it is called a "trap").
> >>
> >> 2012/2/16 Yundi Quan <quanyundi at gmail.com>:
> >> > Dear Sir/Madam,
> >> > When using LSDA+U, it is recommended to first do an LSDA caculation
> and
> >> > then
> >> > turn on U. I first did an LSDA calculation to convergence. Then, I
> >> > turned on
> >> > U. I also did a calculation by turning on U from the very beginning. I
> >> > compared the two results, and found that the later is lower in energy.
> >> > Which
> >> > one is correct?
> >> >
> >> >
> >> >
> >> >
> >> >
> >> > _______________________________________________
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> >> >
> >>
> >>
> >>
> >> --
> >> Professor Laurence Marks
> >> Department of Materials Science and Engineering
> >> Northwestern University
> >> www.numis.northwestern.edu 1-847-491-3996
> >> "Research is to see what everybody else has seen, and to think what
> >> nobody else has thought"
> >> Albert Szent-Gyorgi
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> >
> >
> >
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>
>
>
> --
> Professor Laurence Marks
> Department of Materials Science and Engineering
> Northwestern University
> www.numis.northwestern.edu 1-847-491-3996
> "Research is to see what everybody else has seen, and to think what
> nobody else has thought"
> Albert Szent-Gyorgi
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
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