The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

Dear Hua Bao,

Concerning Al2O3 , you will find an automatic test that precisely  
examine
the different possible settings for geometry : test v1#96 , so please
have a look at the directory tests/v1 , files README, Input/t96.in  
and Refs/t96.out

Xavier

On 22 Aug 2007, at 21:38, Hua Bao wrote:

> Dear abinit-user,
>
> I was trying to do geometry optimization of corundum. And it has  
> such error message,
>
> symanal : COMMENT -
> The Bravais lattice determined only from the primitive
> vectors, bravais(1)= 6, is more symmetric
> than the real one, iholohedry= 1, obtained by taking into
> account the atomic positions.
> symspgr : the symmetry operation no. 1 is the identity
> symspgr : spgroup= 1 P1 (=C1^1)
> getkgrid : length of smallest supercell vector (bohr)= 3.598190E+01
> Simple Lattice Grid
> getkgrid : BUG -
> The argument nkpt= 36, does not match
> the number of k points generated by kptopt, kptrlatt, shiftk,
> and the eventual symmetries, that is, nkpt= 32.
> However, note that it might due to the user,
> if nkpt is explicitely defined in the input file.
> In this case, please check your input file.
> Action : contact ABINIT group.
>
>
> Is that a bug? What is the best way to sample the k-point of such  
> material? And corundum should have a space group 167, why the  
> program think it is simply P1?
>
> My input file is as follow,
> ionmov 3 # Use the modified Broyden algorithm
> ntime 200 # Maximum number of Broyden "timesteps"
> tolmxf 5.0d-4 # Stopping criterion for the geometry optimization :  
> when
>
> chkprim 0
> xangst
> ……
>
> toldff 5.0d-5
>
> nband 72
> #Definition of the unit cell
> acell 4.7602 4.7602 12.9933 angstrom # The keyword "acell" refers  
> to the
> angdeg 90 90 120
>
> ntypat 2 #
> znucl 13 8 # The keyword "znucl" refers to the atomic number of the
>
>
> #Definition of the atoms
> natom 30
> typat 1 1 1 1 1 1 1 1 1 1 1 1
> 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2
>
> #Definition of the planewave basis set
> ecut 30.0 # Maximal kinetic energy cut-off, in Hartree
>
> #Definition of the k-point grid
> ngkpt 4 4 4
> kptopt 1
>
> #Definition of the SCF procedure
> nstep 100 # Maximal number of SCF cycles