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["TORUMBA Doru 218423" <doru.torumba@cea.fr>]

Dear Joe,

Thank you very much for the tip! Strange enough, but it works! 

Best regards,
Doru


> -----Original Message-----
> From: Josef W. Zwanziger [mailto:jzwanzig@jzwanzig.org]
> Sent: Tuesday, December 09, 2008 2:54 PM
> To: forum@abinit.org
> Subject: Re: [abinit-forum] alpha-U structure
> 
> Dear Doru,
> 
> what always seems to work best in these face and base-centered
structures
> is to set acell to 1.0 and carry the vector lengths in rprim. This is
due
> to the way abinit will combine these variables internally. So in your
case
> I would try
> 
> acell 3*1.0
> rprim 2.695 5.552 0.000
>      -2.695 5.552 0.000
>       0.000 0.000 9.3274
> 
> let me know if this doesn't work--
> Joe
> 
>  Josef W. Zwanziger
> Professor of Chemistry
> Canada Research Chair in NMR Studies of Materials
> Director, Atlantic Region Magnetic Resonance Centre
> Department of Chemistry
> Dalhousie University
> 6274 Coburg Road
> Halifax, Nova Scotia B3H 4J3 Canada
> tel: +1.902.494.1960
> fax: +1.902.494.1310
> web: http://jwz.chem.dal.ca
> jzwanzig@jzwanzig.org,jzwanzig@dal.ca
> 
> 
> 
> ----- Original Message ----
> > From: Doru Torumba <doru.torumba@cea.fr>
> > To: forum@abinit.org
> > Sent: Tuesday, December 9, 2008 9:20:27 AM
> > Subject: [abinit-forum] alpha-U structure
> >
> > Dear Abinit users,
> >
> > I am trying to create the alpha-U structure, but for some reason I
do
> not get
> > the correct space group (Cmcm, #63). In this structure there are 2
atoms
> per
> > unit cell. Atomic positions are (y,-y,-1/4) and (-y,y,1/4) in units
of
> Bravais
> > lattice vectors defined by (a/2,-b/2,0),  (a/2,b/2,0), (0,0,c).
Instead
> I get
> > the space group  P2_1/m (#11). Most probably I am overlooking
something
> > obvious, but I can't figure out what. Suggestions are welcome :)
> >
> > #Definition of the unit cell
> > acell 5.39 11.1034 9.3247
> >
> > rprim  0.5  0.5  0.0   # primitive vectors
> >       -0.5    0.5  0.0
> >        0.0    0.0  1.0
> >
> > #Definition of the atom types
> > ntypat 1      # No of atom types
> > znucl 92
> >
> > #Definition of the atoms
> > natom 2               # No of atoms in the cell
> > typat 1 1              # Type of each atom
> >
> > xred
> >     0.10 -0.10    -0.25
> >    -0.10  0.10     0.25
> >
> > #Definition of the planewave basis set
> > ecut 35
> > pawecutdg 40
> >
> > #Exchange-correlation functional
> > ixc 11 #GGA (PBE)
> >
> > #Definition of the k-point grid
> > kptopt 1
> >
> > ngkpt 2 2 2
> > tsmear 0.001
> >
> > #Spin polarization
> > nsppol 1
> >
> > #Definition of occupation numbers
> > occopt 3
> > nband 40
> >
> > #Definition of the SCF procedure
> > nstep 100
> > usepaw 1
> > toldfe 1.0d-6
> > iscf 7