[Pw_forum] volume in output file.

[Stefano de Gironcoli]

Jiayu Dai wrote:
> Dear all users,
>
> When i performed the vc-relax calculation, i found the "unit-cell volume" in the
> output file is not the volume of the supercell i used. I also found it is the same
> in the SCF calculation. For example, in SCF calculation, my input lattice ibrav =2
> (.ie., fcc), celldm(1)=10.6920, then the output parameters are:
>
> lattice parameter (a_0)   =      10.6920  a.u.  -------a
> unit-cell volume          =     305.5743        -------omega
>
> You can see omega is not the cubic of a. Then, how the volume "omega" in the code
> is calculated here? Is it included in the cell_base.f90 file?
>   
omega is the volume of the unit cell which in FCC is not alat^3 but 1/4 
of alat^3

stefano

> Thanks a lot.
>
> Jiayu
>
>
>
>
> ------------------------------
> -------------------------------------------
> Jiayu Dai
> Department of Physics
> National University of Defense Technology, 
> Changsha, 410073, P R China
> -----------------------------------------
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