[Pw_forum] dos

Fri May 8 14:20:14 CEST 2009

On 5/6/09, Stefano Baroni <baroni at sissa.it> wrote:
>
> Cyrille: I totally agree with you, of course. What I was questioning is the
> relevance of taking averages of pdos centered around different centers, not
> the concept of PDOS itself . Concerning Berlusconi's brain, I think that's
> perfectly OK. What is probably not is the brain of those who find his
> behavior appropriate.
>
>
> SB
>
>  On May 6, 2009, at 11:38 AM, Cyrille Barreteau wrote:
>
>  Dear Stefano,
>
> Of course if you take the extreme case of the free electron gas, the
> local PDOS is obviously not more relevant
> than asking what it is s-like in Italy:-) (but maybe we could discover
> some interesting pertubation around Berlusconi brain:-)
> But in many cases  the local PDOS can be very useful to analyze DFT
> results:
>   -local magnetism
>  -surface reactivity
> not to mention transport properties (STM images etc....)
>
> cyrille
>
> --
> ==================================================================
> Cyrille Barreteau  | phone : +33 (0)1 69 08 29 51
> CEA Saclay         | fax   : +33 (0)1 69 08 84 46
> DSM/IRAMIS/SPCSI   | email cyrille.barreteau at cea.fr
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> 91191 Gif sur Yvette Cedex  FRANCE
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> ==================================================================
>
>
>
>
>
> Stefano Baroni wrote:
>
> I am still rather skeptical. If you apply your reasoning to the free
>
> electron gas, it seems to me that you would obtain rather weird (to
>
> say the least) results. I may be wong, and finally the choice on how
>
> to analyze your data is yours. SB
>
>
> On May 5, 2009, at 9:26 AM, Gabriele Sclauzero wrote:
>
>
>
>  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
>
>
>
>  I agree with what you say, Stefano, about taking the expectation
>
>  value of the angular
>
>  momentum in a periodic system, but summing the PDOS of selected atoms
>
>  can lead to
>
>  meaningful and sometimes very useful results, in some cases.
>
>  I usually see the PDOS as an indicator of how much the Bloch states
>
>  retain a kind of
>
>  "atomic character" in the solid (so that in this case summing PDOS of
>
>  equivalent atoms is
>
>  the more meaningful thing, as Lex pointed out), but also as a way to
>
>  identify the symmetry
>
>  of states.
>
>  If you place a molecule, a nanowire or maybe even a surface with slab
>
>  geometry in a wise
>
>  manner in your (super-)cell you can get many information from the
>
>  PDOS (summed or not).
>
>  Obviously, it does not make much sense to sum the s,p,d PDOS of all
>
>  atoms in the system in
>
>  general (but in some cases it may), so that's why you cannot find it
>
>  directly in the
>
>  output from projwfc.
>
>  It's your task to select over which atoms you can do a sum (or an
>
>  average) of the PDOS
>
>  (and also placing the atoms in a smart way, first). I think you can
>
>  write a script in
>
>  awk/perl/whatever, or even a small fortran program, which reads PDOS
>
>  from individual files
>
>  associated to the selected atoms and sums the corresponding rows.
>
>
>  Gabriele
>
>
>
>  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
>
>
>
> ---
>
> Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center - Trieste
>
> http://stefano.baroni.me [+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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>
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dear all
after such considerable discussion my problem to project dos to molecular
(not atomic) orbital (specially antibonding ) has not solved. Please anyone
explain to me.
thanks
yalda
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