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

[xu yuehua]

Dear Ding and Degiron

i  think about my problem again ,i think my lattice not belongs cubic
neither triangular lattice .it is unuall lattice .a=b, the angle of a and b
is 30 degree.a,b plumb c.it is supercell. thank your hints. i have to
redesign it .


2007/5/25, degironc <degironc at sissa.it>:
>
> the word "cubic" is a reminder for the code that the symmetry group of
> the crystal in a subset of the cubic one (the other option would be
> "hexagonal"). this does not means that the system is actually cubic but
> just that the symmetry operations that it satisfies should be searched
> among those of the cubic group.
> .. is "cubic" the right symmetry system for your crystal ? the
> fundamental lattice vectors you get look like belonging to some
> triangular lattice...
> stefa
>
> 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
>
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-- 
Xu Yuehua
physics Department of Nanjing university
China
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