[Pw_forum] Another question about building a spinel structure

[Huiqun Zhou]

ibrav = 2 is correct, but you need to confirm if your atomic positions
are really those that in a PRIMITIVE cell.

Huiqun


----- Original Message ----- 
From: "Chaohao Hu" <chaohao2002 at 163.com>
To: <pw_forum at pwscf.org>
Sent: Thursday, November 09, 2006 2:15 PM
Subject: Re: [Pw_forum] Another question about building a spinel structure


>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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>>Pw_forum at pwscf.org
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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
>
>
>
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