[Pw_forum] phonon dos normalization

[Nicola Marzari]

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
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