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[cszakacs@mun.ca]

That is what I needed, I've learned one more thing :) I didn't know what is
going on, it is the first time when I am performing 0 dimensional calc's on
Abinit.
 
I left the "nstep 10" just to see how things are evolving. I checked again
earlier the job and it did not converged, so probably that was the problem.

So, I will increase the "nstep". Lets see what happens. And I will try with 
the
PAW's too.
Thanks,
Csaba

Quoting Anglade Pierre-Matthieu <anglade@gmail.com>:

> Hi,
> 
> Atoms flying all around the cell is a symptom of unconverged
> calculation. If your SCF cycles converge correctly (your "nstep 10"
> looks quite scary here)  it can be the use of an ecut too low for the
> pseudopotential...
> Have you tried using a PAW pseudopotential ?
> 
> regards
> 
> PMA
> 
> On Wed, Apr 8, 2009 at 10:23 PM,  <cszakacs@mun.ca> wrote:
> > Hello,
> >
> > I have used a lower cutoff, but now I am encountering another problem.
> Even
> > though it didn't fully converged yet, I am detecting some strange things,
> it
> > seems the cluster explodes....the Zn and O atoms are flying all around the
> > box...it is a mess.
> > (I have optimized the same cluster using other software (Gaussian) at HF
> level
> > of theory with no problem, but if I want to tackle significantly larger
> > clusters it will be a problem, that is why I am testing the optimization
> Â with
> > Abinit.)
> > The input file it is the same, as in my earlier email, I've changed the
> ecut and
> > I am using the TM pseudopotentials.
> > Any suggestions?
> > Or I would appreciate any directions to an article or some literature
> which
> > deals with ZnO clusters using Abinit.
> > I've looked around and I didn't find any yet.
> >
> > Thanks,
> >
> > Csaba
> >
> >
> > Quoting matthieu verstraete <matthieu.jean.verstraete@gmail.com>:
> >
> >> your cutoff is huge - you should find softer pseudopotentials, and
> >> converge the box size more systematically, starting with a small one
> >> and looking at different quantites as a function of acell. You may
> >> even have to go to bigger boxes to converge properly.
> >>
> >> Also consider using icoulomb for boundary conditions in the Poisson
> >> solver (places constraints on the box shape and pseudopotentials,
> >> though).
> >>
> >> Matthieu
> >>
> >> On Thu, Apr 2, 2009 at 2:27 PM, Â <cszakacs@mun.ca> wrote:
> >> > Dear users,
> >> >
> >> > I am testing some zero-dimensional calculations with Abinit. I am
> following
> >> the
> >> > example given in Lesson 1 (with the hydrogen).
> >> > I want to optimize a ZnO cluster containing 12 atoms in a supercell (I
> am
> >> > considering it to be neutral). Here is my input:
> >> >
> >> > acell 30 30 30
> >> > ecut 80
> >> > #optimization
> >> > natom 12
> >> > ionmov 3 Â  Â  Â  Â  Â  Â  # Use the modified Broyden algorithm
> >> > ntime 10 Â  Â  Â  Â  Â  Â # Maximum number of Broyden "timesteps"
> >> > tolmxf 5.0d-4 Â  Â  Â  Â # Stopping criterion for the geometry
> optimization :
> >> when
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  # the residual forces are less than
> tolmxf, the
> >> > Broyden
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  # algorithm can stop
> >> > xangst           1.69555300   -0.71202600   -1.53300200
> >> > Â  Â  Â  Â  Â  Â  Â  Â  -0.23112400 Â  Â 1.82435000 Â  -1.53300200
> >> > Â  Â  Â  Â  Â  Â  Â  Â  -1.46439400 Â  -1.11236700 Â  -1.53302300
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â 0.23532700 Â  -1.75354400 Â  -0.85437000
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â 0.23971200 Â  -1.71537200 Â  Â 1.06255400
> >> > Â  Â  Â  Â  Â  Â  Â  Â  -1.63626200 Â  Â 0.67295000 Â  -0.85436900
> >> > Â  Â  Â  Â  Â  Â  Â  Â  -1.60538200 Â  Â 0.65003600 Â  Â 1.06257500
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â 1.40092400 Â  Â 1.08057300 Â  -0.85436500
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â 1.36569300 Â  Â 1.06523600 Â  Â 1.06259300
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â 1.76646300 Â  -0.70453700 Â  Â 1.71357600
> >> > Â  Â  Â  Â  Â  Â  Â  Â  -1.49337800 Â  -1.17754600 Â  Â 1.71354300
> >> > Â  Â  Â  Â  Â  Â  Â  Â  -0.27303100 Â  Â 1.88202800 Â  Â 1.71359200
> >> >
> >> >
> >> >
> >> > toldff 5.0d-5 Â  Â  Â  Â # Will stop the SCF cycle when, twice in a
> row,
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  # the difference between two
> consecutive
> >> evaluations
> >> > of
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  # forces differ by less than toldff
> (in
> >> Hartree/Bohr)
> >> > nband  108            #  band for energy calc
> >> > #Definition of the atom types
> >> > ntypat 2 Â  Â  Â  Â  Â # There is only one type of atom
> >> > znucl 8 30 Â  Â  Â  Â  Â  # The keyword "znucl" refers to the atomic
> number of
> >> the
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # possible type(s) of atom. The
> pseudopotential(s)
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # mentioned in the "files" file must
> correspond
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # to the type(s) of atom. Here, the only type
> is
> >> Hydrogen.
> >> >
> >> >
> >> > #Definition of the atoms
> >> > typat 1 1 1 2 1 2 1 2 1 2 2 2 Â  Â  Â  Â # For the first dataset, both
> numbers
> >> will
> >> > be read,
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # while for the second dataset, only one
> number will be
> >> read
> >> >
> >> > #Definition of the k-point grid
> >> > nkpt 1 Â  Â  Â  Â  Â  Â # Only one k point is needed for isolated
> system,
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # taken by default to be 0.0 0.0 0.0
> >> >
> >> > #Definition of the SCF procedure
> >> > iprcel 45
> >> > nstep 10 Â  Â  Â  Â  Â # Maximal number of SCF cycles
> >> > #toldfe is no more defined, as toldff is used above...
> >> > diemac 2.0 Â  Â  Â  Â # Although this is not mandatory, it is worth to
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # precondition the SCF cycle. The model
> dielectric
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # function used as the standard
> preconditioner
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # is described in the "dielng" input variable
> section.
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # Here, we follow the prescriptions for
> molecules
> >> > Â  Â  Â  Â  Â  Â  Â  Â  Â # in a big box
> >> >
> >> > The main problem I am encountering is the huge memory needed and the
> length
> >> of
> >> > the computation (about 8GB memory and the calculation is runnning now
> for a
> >> few
> >> > days and it didn't finished yet.)
> >> >
> >> > Is this normal? Or I am using a too large ecut?
> >> > I have done before some calculation on the bulk ZnO and using 80 as the
> >> value
> >> > for the ecut I've got good convergence, so I considered that this would
> be
> >> ok.
> >> > Or are there other things that I've missed?
> >> > Or the acell parameters are to high?
> >> >
> >> > Could you give me some advice about this?
> >> >
> >> > Thank you,
> >> >
> >> > Csaba Szakacs
> >> >
> >> >
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> Dr. Matthieu Verstraete
> >>
> >> European Theoretical Spectroscopy Facility (ETSF)
> >> Dpto. Fisica de Materiales,
> >> U. del Pais Vasco,
> >> Centro Joxe Mari Korta, Av. de Tolosa, 72, Â  Phone: +34-943018393
> >> E-20018 Donostia-San Sebastian, Spain        Fax  : +34-943018390
> >>
> >> Mail : matthieu.jean.verstraete@gmail.com
> >> http://www-users.york.ac.uk/~mjv500
> >>
> >>
> >
> >
> > --
> > Csaba Szakacs
> > PhD Candidate
> > Memorial University
> > Dept. of Chemistry
> > St. John's, NL
> > Tel.: 737-6118
> >
> >
> >
> 
> 
> 
> -- 
> Pierre-Matthieu Anglade
> 
> 


-- 
Csaba Szakacs
PhD Candidate
Memorial University
Dept. of Chemistry
St. John's, NL
Tel.: 737-6118