[Pw_forum] Another question about building a spinel structure

[Chaohao Hu]

I am sorry for my careless mistake. "ATOMIC_POSITIONS" should be set to "crystal" 
option. Now this structure is OK. However, for the case of "ibrav= 0", I still 
can not solve it.

>Dear pwscf users,
>Now I want to visualize a spinel structure Al2MgO4 (space group: F-3dm; 227) 
>using XCrySDen. But I can not visualize it rightly. My input files are enclosed 
>here. Please you help me anlysis it.
>=======================================
>cat > spinel.scf.in << EOF
> &control
>    calculation='scf'
>    restart_mode='from_scratch',
>    tstress = .true.
>    tprnfor = .true.
>    prefix='spinel',
>    pseudo_dir = '$PSEUDO_DIR/',
>    outdir='$TMP_DIR/'
> /
> &system    
>    ibrav=  2, celldm(1) =15.2595, nat=  14, ntyp= 3,
>    ecutwfc =36.0
> /
> &electrons
>    conv_thr =  1.0d-8
>    mixing_beta = 0.7
> /
>ATOMIC_SPECIES
> Mg  24.305  Mg.pw91-np-van.UPF
> Al  26.982  Al.pw91-n-van.UPF
> O   15.9994 O.pbe-van_ak.UPF   
>ATOMIC_POSITIONS
>Mg	0.125	0.125	0.125
>Mg	-0.125	-0.125	-0.125
>Al	0.5	0.5	0.5
>Al	0	0.5	0.5
>Al	0.5	0	0.5
>Al	0.5	0.5	0
>O	0.236	0.236	0.236
>O	-0.208	0.236	0.236
>O	0.236	-0.208	0.236
>O	0.236	0.236	-0.208
>O	-0.236	-0.236	-0.236
>O	0.208	-0.236	-0.236
>O	-0.236	0.208	-0.236
>O	-0.236	-0.236	0.208
>K_POINTS {automatic}
> 5 5 5 1 1 1
>EOF
>==========================================
>
>However, when I change  "ibrav" from 2 to 0, some error information always 
>appears as following:
>========================
>invalid number: incomprehensible list input
>apparent state: unit 5 (unnamed)
>last format: list io
>lately reading sequential formatted external IO
>========================
>
>cat > spinel.scf.in << EOF
> &control
>    calculation='scf'
>    restart_mode='from_scratch',
>    tstress = .true.
>    tprnfor = .true.
>    prefix='spinel',
>    pseudo_dir = '$PSEUDO_DIR/',
>    outdir='$TMP_DIR/'
> /
> &system    
>    ibrav=  0, celldm(1) =15.259, nat=  14, ntyp= 3,
>    ecutwfc =36.0
> /
> &electrons
>    conv_thr =  1.0d-8
>    mixing_beta = 0.7
> /
>ATOMIC_SPECIES
> Mg  24.305  Mg.pw91-np-van.UPF
> Al  26.982  Al.pw91-n-van.UPF
> O   15.9994 O.pbe-van_ak.UPF   
>ATOMIC_POSITIONS
>Mg	0.125	0.125	0.125
>Mg	-0.125	-0.125	-0.125
>Al	0.5	0.5	0.5
>Al	0	0.5	0.5
>Al	0.5	0	0.5
>Al	0.5	0.5	0
>O	0.236	0.236	0.236
>O	-0.208	0.236	0.236
>O	0.236	-0.208	0.236
>O	0.236	0.236	-0.208
>O	-0.236	-0.236	-0.236
>O	0.208	-0.236	-0.236
>O	-0.236	0.208	-0.236
>O	-0.236	-0.236	0.208
>K_POINTS {automatic}
> 5 5 5 1 1 1
>CELL_PARAMETERS
> 0.0000 0.5000 0.5000
> 0.5000 0.0000 0.5000
> 0.5000 0.5000 0.0000
>EOF
>===========================================
>How to solve this problem?
>
>Best regards,
>Chaohao
>
>============================================================
>Dr. Chaohao Hu
>Institute of Metal Research, Chinese Academy of Sciences--IMR
>Wenhua Road, 72
>110016, Shenyang, Liaoning (China)
>Phone: +86-024-23971641
>Email: chhu at imr.ac.cn
>
>
>
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Thanks in advance.
Best regards,
Chaohao

============================================================
Dr. Chaohao Hu
Institute of Metal Research, Chinese Academy of Sciences--IMR
Wenhua Road, 72
110016, Shenyang, Liaoning (China)
Phone: +86-024-23971641
Email: chhu at imr.ac.cn