The ABINIT Users Mailing List ( CLOSED )

[Michel Cote <Michel.Cote@umontreal.ca>]

Try commenting out the spgroup keyword. Since you give the position of  
all the atoms, there is no need to specify the space group. Abinit  
should figure it out and this is a good check.

The spgroup assignment is used with natrd where only not equivalent  
atoms are listed.

Michel

Le 08-04-15 à 08:38, Enrico a écrit :

> Hi,
> i tried to get the ground state energy of LaNi2  (like structure  
> Cu2Mg)
> spcgrp 227
> PEARSON cF24
> i use the rprim matrix for FCC
> I got many  xred (see my input ) but none worked!
>
> ERROR -
>  According to the symmetry finder, the unit cell is
>  NOT primitive. The multiplicity is  4 .
>  The use of non-primitive unit cells is allowed
>  only when the input variable chkprim is 0.
>  Action : either change your unit cell (rprim or angdeg),
>  or set chkprim to 0.
>
> If i use chkprim the calculation stops , geometry not consistent  
> with the
> spacegrp!
>
> INPUT
> #UNIT CELL
> LaNi2
>
> acell  3*7.387 Angstr
>
> rprim  0.0  0.5  0.5   # Real space PRIMitive translations
>       0.5  0.0  0.5
>       0.5  0.5  0.0
>
> spgroup 227 # without space group the spcgrp is not identified
>
> ntypat 2 # 2 types of atoms
>
> znucl  57 28
>
> natom  6 # atom per cell
>
> typat  1 1 2 2 2 2 # LaNi2
>
> xred
>
> #internatinal table of crystallography origin -3m
> #1/8 1/8 1/8 # 8a wyckoff position
> #7/8 3/8 3/8
> #1/2 1/2 1/2 # 16d
> #1/2 1/4 1/4
> #1/4 1/2 1/4
> #1/4 1/4 1/2
>
> #internatinal table of crystallography origin -43m
> 0.0 0.0 0.0 #
> 1/4 1/4 1/4
> 5/8 5/8 5/8
> 5/8 7/8 7/8
> 7/8 5/8 7/8
> 7/8 7/8 5/8
>
> #setting input VASP
> #0.0 0.0 0.0 #  Pearson book notation NOT WORKING
> #1/4 1/4 1/4
> #5/8 5/8 5/8 # Pearson book
> #5/8 1/8 5/8
> #1/8 5/8 5/8
> #5/8 5/8 1/8
>
> FROM THIS POINT IT SHOULD BE OK, BUT HAVE A
>
> #RECIPROCAL SPACE INTEGRETION
> kptopt 1
> ngkpt 2 2 2
>
> nshiftk 4            # shiftk=4 particular efficient for FCC
> shiftk 0.5 0.5 0.5
>       0.5 0.0 0.0
>       0.0 0.5 0.0
>       0.0 0.0 0.5
>
> nband 25
> tsmear 0.02
> occopt 4
>
> #PLANE WAVES
> ecut 20
>
> #SCF PROCEDURE
> nstep 50
> ixc 1
> toldfe 1.0d-7
>
> thank you, hope you could help!

_____________________________________
Michel Cote
Departement de physique
Universite de Montreal
email: Michel.Cote@umontreal.ca
web: http://www.phys.umontreal.ca/~michel_cote