[Pw_forum] uncertainty about the *.dynG file :what is "cubic" mean ? and what is the difference between *.dyn and *. matdyn file ?

[Xunlei Ding]

Hi Xu,

You can find the same numbers in your scf output files:
     crystal axes: (cart. coord. in units of a_0)
               a(1) = (  0.866026  0.499999  0.000000 )
               a(2) = (  0.000000  0.999999  0.000000 )
               a(3) = (  0.000000  0.000000  0.143563 )

So I think "cubic" means a cubic cell, not  hexagonal .

Best wishes,
Ding

xu yuehua wrote:

> hi all :
> In the *.dynG file ,there is "cubic" ,i don know what is meaning 
> ,because my cell is not the type as you can see my scf file
>  
>  
>  
> -------------------------------------dynG.FILE 
> ------------------------------
>
> Dynamical matrix file
>
>   2   15  0 38.1852405  0.0000000  0.0000000  0.0000000  0.0000000  
> 0.0000000
> cubic
>       0.866025710    0.499999470    0.000000000
>       0.000000000    0.999998940    0.000000000
>       0.000000000    0.000000000     0.143563323
>
> ------------------------------------------------------------------------scf 
> file -----------------------------------
> this is the scf output :
>
> bravais-lattice index     =            0
>      lattice parameter (a_0)   =      38.1852  a.u.
>      unit-cell volume          =    6922.4594 (a.u.)^3
>      number of atoms/cell      =           15
>      number of atomic types    =            2
>      kinetic-energy cutoff     =      29.9874  Ry
>      charge density cutoff     =     200.0000  Ry
>      convergence threshold     =      1.0E-09
>      beta                      =       0.2000
>      number of iterations used =            8  plain     mixing
>      Exchange-correlation      =  SLA  PW   PBE  PBE (1434)
>      celldm(1)=  38.185240  celldm(2)=   0.000000  celldm(3)=   0.000000
>      celldm(4)=   0.000000  celldm(5)=   0.000000  celldm(6)=   0.000000
>
>      crystal axes: (cart. coord. in units of a_0)
>                a(1) = (  0.866026  0.499999  0.000000 )
>                a(2) = (  0.000000  0.999999  0.000000 )
>                a(3) = (  0.000000  0.000000  0.143563 )
>
>  
>  
>  
>  
>  
>  
>  
>  
>  
>
>
> -- 
> Xu Yuehua
> physics Department of Nanjing university
> China