[Pw_forum] dos

Mon May 4 18:28:52 CEST 2009

that's a very good point. so far in the literature I've seen plots only of TDOS and PDOS of s, p and d components. I have never seen plotting components of a single atom. 

I just googled the first available reference PWSCF DOS calculations: Koichiro Umemoto1, Renata M. Wentzcovitch,  Lan Wang1, and Chris Leighton, Electronic structure of Co1–xFexS2, phys. stat. sol. (b) 243, No. 9, 2117–2121 (2006). In page 2118 there is a simple DOS and PDOS for CoS2, plotted as TDOS, PDOS Co3d, PDOS S3s and S3p. That is what I would like to get. I am sure they got s, p and d components for every single atom, too. The question is how it can be "averaged"

And yes, I will look at two other suggestions

I appreciate your help

Jonas

--- On Mon, 5/4/09, Stefano Baroni <baroni at sissa.it> wrote:

> From: Stefano Baroni <baroni at sissa.it>
> Subject: Re: [Pw_forum] dos
> To: jasius_1 at yahoo.com, "PWSCF Forum" <pw_forum at pwscf.org>
> Date: Monday, May 4, 2009, 8:55 AM
> Jonas: I am afraid that what you want to obtain does not
> make much sense. The angular character of any molecular (or
> Bloch) state depends on the origin of your reference system.
> What is "s-like" with respect to one point has an
> infinite number of angular components with respect to a
> different point. Are you sure you want to add "what is
> s-like in Iowa" with "what is s-like in
> Italy" ??? ;-)
> Stefano
> 
> On May 4, 2009, at 5:51 PM, Jonas Baltrusaitis wrote:
> 
> > 
> > I just successfully calculated DOS and PDOS of a very
> large system. One thing that confuses me is the presence of
> s, p components to PDOS for every atom, but not summed (or
> averaged) s and p contribution of all system. I would be
> happy to find in my output total DOS, PDOS s character and
> PDOS p character. Is there a way to get that instead of
> contribution per every atom? Or how do I proceed to get s
> and p PDOS for all system by manually processing all of my
> 76 atoms PDOS outputs?..
> > 
> > thanks
> > 
> > Jonas Baltrusaitis
> > University of Iowa
> > 
> > 
> > --- On Mon, 5/4/09, Prasenjit Ghosh
> <prasenjit.jnc at gmail.com> wrote:
> > 
> >> From: Prasenjit Ghosh
> <prasenjit.jnc at gmail.com>
> >> Subject: Re: [Pw_forum] dos
> >> To: jasius_1 at yahoo.com, "PWSCF Forum"
> <pw_forum at pwscf.org>
> >> Date: Monday, May 4, 2009, 12:04 AM
> >> Hi Jonas,
> >> 
> >> For DOS calculations one needs to do an
> integration over
> >> the kpts in the
> >> Brillouin zone. So you need a very fine k-point
> mesh than
> >> necessary for a
> >> scf calculation. Moreover you need a large number
> of bands.
> >> Doing an scf
> >> calculation with such a fine k-point mesh and so
> many bands
> >> is very
> >> expensive. So you should first do an scf
> calculation with
> >> the min. no. of
> >> k-points and bands and then do a nscf calculation
> with a
> >> finer k-point and
> >> larger no. of bands. In the nscf step, the code
> does an
> >> interpolation for
> >> the extra bands and k-points and not a
> self-consistent
> >> calculation. This
> >> saves computational time.
> >> 
> >> Hope this helps.
> >> 
> >> Prasenjit.
> >> 
> >> 2009/5/3 Jonas Baltrusaitis
> <jasius_1 at yahoo.com>
> >> 
> >>> 
> >>> Prasenjit,
> >>> 
> >>> could you explain why both scf followed by
> nscf
> >> calculations are needed for
> >>> DOS calculations, as per example 8? If only
> scf
> >> density is needed for
> >>> further projection, why not to calculate only
> one?
> >>> 
> >>> Jonas
> >>> 
> >>> 
> >>> --- On Sun, 5/3/09, Prasenjit Ghosh
> >> <prasenjit.jnc at gmail.com> wrote:
> >>> 
> >>>> From: Prasenjit Ghosh
> >> <prasenjit.jnc at gmail.com>
> >>>> Subject: Re: [Pw_forum] dos
> >>>> To: "PWSCF Forum"
> >> <pw_forum at pwscf.org>
> >>>> Date: Sunday, May 3, 2009, 2:00 PM
> >>>> dear all user
> >>>>> 
> >>>> 
> >>>> Dear Yaldaa,
> >>>> 
> >>>> 
> >>>>> How can I project dos to molecular
> orbital?
> >>>>> 
> >>>> 
> >>>> There is a post-processing tool called
> projwfc.x
> >> which you
> >>>> can use to
> >>>> project dos to molecular orbital.
> >>>> 
> >>>> what is the importance of nbnd in
> calculations
> >> for dos?
> >>>>> 
> >>>> e
> >>>> "nbnd"  tells the code the no.
> of
> >> Kohn-Sham
> >>>> states it has to
> >>>> compute.....While computing the dos, one
> wants to
> >> plot the
> >>>> dos for both the
> >>>> occupied & unoccupied manifold, the
> no. of
> >> energy
> >>>> levels is read in by the
> >>>> dos.x from the output of your scf/nscf
> run. So
> >> while doing
> >>>> an scf/ nscf
> >>>> calculations you can control the total no.
> of
> >> states with
> >>>> the variable
> >>>> "nbnd".
> >>>> Depending on the type of occupation scheme
> you
> >> choose the
> >>>> value of nbnd is
> >>>> nelec/2 (fixed occupation)  or
> nelec/2+some extra
> >> bands
> >>>> (when you use
> >>>> smearing). If you want to plot the dos,
> usually
> >> you should
> >>>> add some extra
> >>>> levels using nbnd & do the scf or nscf
> >> calculations to
> >>>> get the unoccupied
> >>>> manifold.
> >>>> 
> >>>> and for plottingdos or pdos, if the fermi
> energy
> >> is assumed
> >>>> to be zero
> >>>>> automatically by program?
> >>>>> 
> >>>> 
> >>>> No, you have to do the alignment yourself
> >>>> 
> >>>> With regards,
> >>>> 
> >>>> Prasenjit.
> >>>> 
> >>>> 
> >>>> 
> >>>> --
> >>>> PRASENJIT GHOSH,
> >>>> POST-DOC,
> >>>> ROOM NO: 265, MAIN BUILDING,
> >>>> CM SECTION, ICTP,
> >>>> STRADA COSTERIA 11,
> >>>> TRIESTE, 34104,
> >>>> ITALY
> >>>> PHONE: +39 040 2240 369 (O)
> >>>>             +39 3807528672 (M)
> >>>>
> _______________________________________________
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> >>>> Pw_forum at pwscf.org
> >>>> 
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> >>> 
> >>> 
> >>> 
> >>>
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> >>> 
> >> 
> >> 
> >> 
> >> --PRASENJIT GHOSH,
> >> POST-DOC,
> >> ROOM NO: 265, MAIN BUILDING,
> >> CM SECTION, ICTP,
> >> STRADA COSTERIA 11,
> >> TRIESTE, 34104,
> >> ITALY
> >> PHONE: +39 040 2240 369 (O)
> >>             +39 3807528672 (M)
> > 
> > 
> > 
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> 
> ---
> Stefano Baroni - SISSA  &  DEMOCRITOS National
> Simulation Center - Trieste
> [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)
> 
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