[Pw_forum] cell dm (1) for (8,0) nanotube

[Lorenzo Paulatto]

On 05/24/2013 08:30 AM, Banafshe Noori wrote:
> Dear all
>
> I am going to constructed a cell of (8 ,0 ) nanotubes with 48  carbon 
> atom or 80 atom.
>
> but i dont know ,how much determine value of cell dm(1)?
> cell dm(1) =?
>
celldm(1) is arbitrary if you specify the cell by hand via 
CELL_PARAMETERS. In fact in the most recent versions of the code it is 
recommended to not set it if ibrav=0, but to specify the cell as 
Angstrom or Bohr with the corresponding keyword:
CELL_PARAMETERS angstrom
... cell in angstrom ...

or
CELL_PARAMETERS bohr
... cell in bohr ...

On the other hand, if ibrav is different from 0, you have to check the 
corresponding cell definition in PW/Doc/INPUT_PW.txt and set celldm(1) 
accordingly (in bohr).

best regards

-- 
Dr. Lorenzo Paulatto
IdR @ IMPMC -- CNRS & Université Paris 6
phone: +33 (0)1 44275 084 / skype: paulatz
www:   http://www-int.impmc.upmc.fr/~paulatto/
mail:  23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 05

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