[Pw_forum] dos

[Jonas Baltrusaitis]

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)
> > > _______________________________________________
> > > Pw_forum mailing list
> > > Pw_forum at pwscf.org
> > >
> http://www.democritos.it/mailman/listinfo/pw_forum
> >
> >
> >
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://www.democritos.it/mailman/listinfo/pw_forum
> >
> 
> 
> 
> -- 
> 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)