[Pw_forum] dos

Mon May 4 19:23:34 CEST 2009

yep, the reply was swift. that's why I come to this forum

--- 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: "PWSCF Forum" <pw_forum at pwscf.org>
> Date: Monday, May 4, 2009, 8:57 AM
> ... and pardon us if it took eight minutes to get three
> decent answers ...
> Enjoy! Stefano
> 
> On May 4, 2009, at 5:55 PM, Stefano Baroni wrote:
> 
> > 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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> >>>> 
> >>>> 
> >>>> 
> >>>>
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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)
> > 
> > La morale est une logique de l'action comme la
> logique est une morale de la pensée - Jean Piaget
> > 
> > Please, if possible, don't  send me MS Word or
> PowerPoint attachments
> > Why? See: 
> http://www.gnu.org/philosophy/no-word-attachments.html
> > 
> > 
> > 
> > 
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> 
> 
> 
> ---
> Stefano Baroni - SISSA  &  DEMOCRITOS National
> Simulation Center - Trieste
> [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)
> 
> La morale est une logique de l'action comme la logique
> est une morale de la pensée - Jean Piaget
> 
> Please, if possible, don't  send me MS Word or
> PowerPoint attachments
> Why? See: 
> http://www.gnu.org/philosophy/no-word-attachments.html
> 
> 
> 
> 
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