[QE-users] Fwd: SPACE GROUP-POINT GROUP ERROR

[Paolo Giannozzi]

This typically happens when your atomic positions are not exactly 
symmetric with the symmetry you are assuming ("exactly" = "according to 
the criteria used by QE"). It is not possible to say more since you did 
not report your atomic positions

Paolo


On 8/15/2025 10:01 AM, Barsha Pal wrote:
> 	
> Hello, I have a structure which has ibrav=6, Tetragonal P lattice, I am 
> using celldm 1 and 3.
> My desired symmetry group is P-421m with space group 113. But when I run 
> my structure it shows point group :
> 
>       point group C_2v (mm2)
>       there are  4 classes
>       the character table:
> 
>         E     C2    s_v   s_v'
> A_1    1.00  1.00  1.00  1.00
> A_2    1.00  1.00 -1.00 -1.00
> B_1    1.00 -1.00  1.00 -1.00
> B_2    1.00 -1.00 -1.00  1.00
> 
> 
> This point group is not possible in Tetragonal (ibrav =6). It belongs to 
> the orthorhombic lattice with space group no 35. I don't understand what 
> the error is.  How do I decide my lattice and point group? (space group 
> 113 was confirmed by another software for the same structure)
> 
> 
> input file is this :
> 
> 
> &CONTROL
>      calculation = "scf"
>      outdir      = "/path/"
>      prefix      = "name"
>      pseudo_dir  = "/path/"
>      verbosity     = "high"
> /
> 
> &SYSTEM
>      celldm(1)   =  12.99636895
>      celldm(3)   =  2.211372174
>      degauss     =  1.00000e-02
>      ecutrho     =  1440
>      ecutwfc     =  180
>      ibrav       =  6
>      nat         =  8
>      ntyp        =  2
>      occupations = "smearing"
>      smearing    = "gaussian"
> /
> 
> &ELECTRONS
>      conv_thr         =  1.00000e-08
>      electron_maxstep =  200
>      mixing_beta      =  7.00000e-01
> /
> 
> K_POINTS {automatic}
>   10  10  1  0  0  0
> 
> ATOMIC_SPECIES
> A  0   A.pbe-dnl-rrkjus_psl.1.0.0.UPF
> B   0   B.pbe-nl-rrkjus_psl.1.0.0.UPF
> 
> ATOMIC_POSITIONS {crystal}
> 
> 
> 
> 
> Kindly guide me.
> 
> 
> Ashley Cooper
> 
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-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216