[Pw_forum] phonon dos normalization

[Mousumi Upadhyay Kahaly]

Dear Sir & all,

         I am in "Siesta" mailing list too, for calculations of "large no
of atoms".  And some time back when the mail came, by some bad chance, I
mistook the pw forum mail with siesta mail.... and thus created all these
problems.

          I am sorry again.    mousumi.
>
>
> Hi Mousumi,
>
> no problems ! It's very important to know what to have first,
> the siesta, or the espresso.
>
> (Sorry, I couldn't resist).
>
>
> 				nicola
>
>
> Mousumi Upadhyay Kahaly wrote:
>
>> Hi, I am extremely sorry for my wrong mail.
>>
>> I mistook PWSCF with "Siesta" and in Siesta, following is the cause for
>> getting phonon FC matrix size = 2 times the total degrees of freedom.
>>
>> Am really sorry,   mousumi.
>>
>>
>>
>>>On Sep 9, 2005, at 12:42 PM, Mousumi Upadhyay Kahaly wrote:
>>>
>>>
>>>>Hi,
>>>>
>>>>In order to cancel first order errors in d/dx form,
>>>>and to get better results, each atom is once displaced by
>>>>+delta and then by -delta. Then Dynamical matrices are
>>>>calculated. Hence matrix size= 2 times the total degrees
>>>>of freedom, i.e. twice what you expect.
>>>
>>>???
>>>
>>>May I suggest that only people who i) unrerstand questions and ii)
>>>know sensible answers provide the latter?
>>>
>>>SB
>>>
>>>
>>>
>>>>regards.
>>>>
>>>>
>>>>
>>>>
>>>>>Dear PW users,
>>>>>
>>>>>After several testing, I found that the phonon density
>>>>>of state from the PWscf calculations are normalized to
>>>>>six times the number of atoms in a unit cell. That is
>>>>>twice of the degrees of freedom. I wonder why don't we
>>>>>just normalize it to the degrees of freedom or just to
>>>>>one?
>>>>>
>>>>>I would appreciate it very much if someone could give
>>>>>me an explanation.
>>>>>
>>>>>W. YU
>>>>>
>>>>>
>>>>>
>>>>>
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>>>>
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>>>
>>>---
>>>Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -
>>>Trieste
>>>[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)
>>>
>>>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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>
> --
> ---------------------------------------------------------------------
> Prof Nicola Marzari   Department of Materials Science and Engineering
> 13-5066   MIT   77 Massachusetts Avenue   Cambridge MA 02139-4307 USA
> tel 617.4522758  fax 617.2586534  marzari at mit.edu  http://nnn.mit.edu
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