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["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi,

Here is a modification of you input file that works. Unforunately, in
this case the convenitional cell is not primitive making the
calculation a little bit unoptimised ...
I have put :
rprim 1 0 0 0 1 0 0 0 1
natrd 2
natom 24 #8+16
chkprim 0

regards

PMA

On Thu, Oct 23, 2008 at 9:32 AM, Andrey Chibisov
<andreichibisov@yandex.ru> wrote:
> Post my input file for beta Cristobalite:
> ndtset 4
>
> #Optimization of the lattice parameters
> enunit 1
> optcell 1
> ionmov 3
> tolmxf 5.0d-4
> ntime 500
> dilatmx 1.1
> ecutsm 0.5
>
> #Definition of the k-point grids
> kptopt 1 # Option for the automatic generation of k points, taking
> # into account the symmetry
> nshiftk 1
> shiftk 0.0 0.0 0.0
>
> ngkpt1 2 2 2
> ngkpt2 4 4 4
> ngkpt3 6 6 6
> ngkpt4 8 8 8
>
> getwfk -1 # This is to speed up the calculation, by restarting
> # from previous wavefunctions, transferred from the old
> # to the new k-points.
>
> #Definition of the unit cell
> spgroup 227
> acell 3*13.52856
> angdeg 90 90 90
> rprim 0.0 0.5 0.5 # FCC primitive vectors (to be scaled by acell)
> 0.5 0.0 0.5
> 0.5 0.5 0.0
>
> #Definition of the atom types
> ntypat 2 # There is only one type of atom
> znucl 14 8
> zion 4 6 # The keyword "znucl" refers to the atomic number of the
> # possible type(s) of atom. The pseudopotential(s)
> # mentioned in the "files" file must correspond
> # to the type(s) of atom. Here, the only type is Silicon.
>
>
> #Definition of the atoms
> natom 2 # There are two atoms
> typat 1 2 # 1=Si 2=O
> xred
> 0.125 0.125 0.125 #Si
> 0.000 0.000 0.000 #O
>
> #Definition of the planewave basis set
> ecut 30.0 # Maximal kinetic energy cut-off, in Hartree
>
> #Definition of the SCF procedure
> nstep 500 # Maximal number of SCF cycles
> toldfe 1.0d-6 # Will stop when, twice in a row, the difference
> # between two consecutive evaluations of total energy
> # differ by less than toldfe (in Hartree)
>
> 22.10.08, 10:56, "Anglade Pierre-Matthieu" <anglade@gmail.com>:
>
>
>
> Hi,
> Could you please post your input file ?
> Theoretically (and in practice (see test 24 in the v3 serie)) abinit
> can perform your calculation in spgroup 227 without problem. Thus, it
> could be quite helpful to see your input file in order to know what
> the problem could be.
> regards
> PMA
> On Wed, Oct 22, 2008 at 7:04 AM, Andrey Chibisov
> <andreichibisov@yandex.ru> wrote:
>
> Can you help me with unit cell of Cristobalite?
> Data for Cristobalite from site http://rruff.geo.arizona.edu/AMS/amcsd.php 
> (American Mineralogist Crystal Structure Database) is:
>
> Title Cristobalite
> Lattice type F
> Space group name Fd-3m
> Space group number 227
> Setting number 1
>
> Lattice parameters
> a b c alpha beta gamma
> 7.16600 7.16600 7.16600 90.0000 90.0000 90.0000
> Unit-cell volume = 367.985229
> Structure parameters
> x y z g B
> 1 Si Si 0.12500 0.12500 0.12500 1.000 3.335
> 2 O O 0.00000 0.00000 0.00000 1.000 7.146
>
> In the input abinit file I write:
> spgroup 227
> For the primitive vectors of the lattice form a FCC lattice:
> rprim
> 0.0 0.5 0.5
> 0.5 0.0 0.5
> 0.5 0.5 0.0
> However the abinit gives out:
> Unit cell is not primitive?
> In what is my error?
>
> --
> Andrey Chibisov.
> Candidate of Science,
> Structural Ceramics Laboratory
> Institute of Geology and Nature Management
> Far Eastern Branch of Russian Academy of Sciences
>
> --
> Pierre-Matthieu Anglade
>
>
> --
> Andrey Chibisov.
> Candidate of Science,
> Structural Ceramics Laboratory
> Institute of Geology and Nature Management
> Far Eastern Branch of Russian Academy of Sciences
>
>
>



-- 
Pierre-Matthieu Anglade