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[James Johns <jej7x@xenon.cchem.berkeley.edu>]

ok, so that works for the bulk crystal, but now I want to expand it 
along the 111 direction so that I have vacuum, metal, vacuum.  This point 
at 1/3 2/3 2/3 is not on the 111 surface right?  How then do I extend my 
rpim?

On Mon, 26 Jun 2006, Anglade Pierre-Matthieu wrote:

> Hi,
>
> I might mistake but try (1/3, 2/3, 2/3) as your third atom
> coordinates. This is eqivalent to the atom in (0.5 1 0.5) in the cubic
> cell.
>
> reagrds
>
> PMA
>
> On 6/25/06, jej7x@xenon.cchem.berkeley.edu
> <jej7x@xenon.cchem.berkeley.edu> wrote:
> > Hi, I'm pretty new to abinit, and I'm trying to look at the 111 surface of 
> > Ag.  To do that, I'm trying to follow my way through the
> > tutorials, and so I'm starting with tutorial #4, and adapting that to the 
> > 111 surface.  As a first step, I tried adjusting rprim so that
> > one of my axes will be along the 111 direction, and the other 2 would stay 
> > in the 111 plane.  So I created the following input file.  When
> > I use this, everything converges with no warnings, but the ions end up at 
> > the following coordinates
> > xred
> > 0.0 0.0 -.036307
> > 2/3 1/3 0.277767859
> > 0.0  1.0 5.91873013
> > These changes are on the order of -.2 to -.4 bohr in the 111 direction
> >
> >
> > However, if I change my  coordinates back to the typical fcc lattice
> > (rprim = 0.5 0.5 0
> >          0.5 0.0 0.5
> >           0.0 0.5 0.5
> > natom 1
> > xred 0.0 0.0 0.0)
> > I get no ion movement, and it says that at MD/Broyden step 0, all gradients 
> > converged.   It also gives no xred, xcart, or xangst in the
> > output file (I assume b/c they didn't change). Did I just redefine the FCC 
> > crystal using a poor (or even plain outright wrong) basis?
> > Help would be awesome.
> > --James
> >
> > --------------------------------------------------------------------------
> > #Bulk Aluminum FCC crystal (I hope)
> >
> > occopt 4
> > tsmear 0.04
> > nband 8
> > kptopt 1
> > ngkpt 6 6 6
> > nshiftk 1
> > shiftk 0.5 0.5 0.5
> >
> >
> >  #Definition of the unit cell
> > acell 3*7.50559090E+00   # Lattice parameters of bulk aluminum
> > rprim  0.5 0.0  -0.5     # These values will define a cell with three 
> > atoms,
> >        -0.5  0.5  0.0     # non-primitive, with a different orientation
> >        1.0  1.0  1.0     # than the primitive cell.
> > chkprim 0
> > ntypat 1
> > znucl 13
> >
> > #Definition of the atoms
> > natom 3
> > typat 3*1
> > xred 0.0 0.0 0.0
> >       2/3 1/3 1/3
> >      0.0   1.0 0.5
> >
> > #Convergence Criteria
> > ionmov 2
> > tolmfx 1d-4
> > ntime 15
> > getwfk  -1
> > nstep 10
> > toldfe 1d-6
> >
> > -------------------------------------------------------------------------------