The ABINIT Users Mailing List ( CLOSED )

[Masayoshi Mikami <mmikami@rc.m-kagaku.co.jp>]

Hello,

You might want to run through the Tutorials "STEP BY STEP"
before your project... The explanations for the keywords are available :
        http://www.abinit.org/package/?text=varindex
linked from http://www.abinit.org/package/?text=package

I would suggest that you would download relevant papers
that seems close to your models. You might find here:
        http://www.abinit.org/community/?text=bib
and learn computational conditions such as ecut etc.
Your ecut is way too small... nband should also be small.
(Is there a TiO2 crystal with Z=1 ?!  "nband 8" means that.
 And one more thing: Ti will need the shallow-core for the oxide.
 So you should adopt Ti pseudopotential having 12 valence electrons)
Some other parameters (nstep) seems to be tuned...

Then take your time to run/read  the basics tutorials.
        http://www.abinit.org/Infos_v5.2/tutorial/welcome.html  
Kindly remember, "Slow and but steady wins the race."
(or, "Spare the rod and spoil the child." ? ;-) )

Good luck,
Masayoshi

On 2007/04/24, at 16:16, taoj0003@ntu.edu.sg wrote:

> Hi,
> I m a new user of ABINIT. I want to calculate the TiO2 rutile  
> structure as beginning. I dont know much about those parameters,  
> anyone can give me an suggestion or example? I tried to do so by  
> change some parameter from Tutorial t35. Any one can help me check  
> whether my change is ok or not. thanks
>
>
>
> # Crystalline TiO2
> #
> # Computation of the band structure.
> # First, a SCF density computation, then a non-SCF band structure  
> calculation.
>
>
> ndtset 2
> prteig 1
> #Dataset 1 : usual self-consistent calculation
> kptopt1 1          # Option for the automatic generation of k points,
>                    # taking into account the symmetry
> chkprim  0
> prtden1  1         # Print the density, for use by dataset 2
>
> toldfe1  1.0d-6
>
> #the band structure
> iscf2    -2
> getden2  -1
> kptopt2  -3
> nband2   8
>
> ndivk2   10 12 17      # 10, 12 and 17 divisions of the 3 segments,  
> delimited
>                        # by 4 points.
> kptbounds2  0.5  0.0  0.0 # L point
>             0.0  0.0  0.0 # Gamma point
>             0.0  0.5  0.5 # X point
>             1.0  1.0  1.0 # Gamma point in another cell.
> tolwfr2  1.0d-12
> enunit2  1             # Will output the eigenenergies in eV
>
>
> #Definition of the unit cell
> acell 4.59  4.95 2.96 angstrom
>
> #Definition of the atom types
> ntypat 2          # There is only one type of atom
> znucl 22  8       # 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 6           # There are two atoms
> typat 1 1 2 2 2 2 # They both are of type 1, that is, Silicon.
> xred              # This keyword indicate that the location of the  
> atoms
>                   # will follow, one triplet of number for each atom
>    0.0   0.0   0.0    # Triplet giving the cartesian coordinates of  
> atom 1,
>    0.5   0.5   0.5    # Triplet giving the cartesian coordinates of  
> atom 2
>    0.305 0.305 0.0    # Triplet giving the cartesian coordinates of  
> atom 3
>    0.695 0.695 0.0    # Triplet giving the cartesian coordinates of  
> atom 4
>    0.195 0.195 0.5    # Triplet giving the cartesian coordinates of  
> atom 5
>    0.805 0.805 0.5    # Triplet giving the cartesian coordinates of  
> atom 6
>
>
> #Definition of the planewave basis set
> ecut 1.0         # Maximal kinetic energy cut-off, in Hartree
>
> #Definition of the SCF procedure
> nstep 10          # Maximal number of SCF cycles
> diemac 12.0       # Although this is not mandatory, it is worth to
>                   # precondition the SCF cycle. The model dielectric
>                   # function used as the standard preconditioner
>                   # is described in the "dielng" input variable  
> section.