[QE-users] X-CrysDen atomic position error

[Giovanni Cantele]

sorry, at some point of my message I (or the automatic correction) wrote
CaO has a cubic bcc lattice
that instead was meant
CaO has a cubic fcc lattice

Giovanni

> On 17 Dec 2019, at 10:47, Giovanni Cantele <giovanni.cantele at spin.cnr.it> wrote:
> 
> You’re using ibrav=2, which corresponds to a cubic F (fcc). The atomic positions are in alat units. As such, as clearly stated by the error message,
> atoms 1 and 2 are equivalent. Indeed, their positions are:
> #1 --> a/2 a/2   0
> #2 —>   0    0   0
> 
> Atom #1 lies at the center of a face, its position for a cubic bcc lattice is obtained by translating the lattice site at the origin (where atom #2 lies)
> by a direct lattice vector. 
> 
> You must specify *ONLY* inequivalent atoms, their periodic replicas cannot be included in the list of atoms. There are many other similar
> overlapping atoms, such as
> Ca —> 0 0 0 with Ca —> 1 1 0 or Ca —> 0 0 1.
> 
> Actually, to be honest, you should probably remove *ALL ATOMS BUT TWO*. Indeed, as far as I remember, CaO has a cubic bcc lattice
> with on Ca atom in 0 0 0 and on O atom in a/2 a/2 a/2 (but please check!).
> 
> Provided that, in my opinion, any question is welcome, my suggestion is that you try to give a solution to error messages by yourself before
> asking people, because what you learn if you “try to solve” is priceless if compared to what you learn if you “ask to solve”. In this respect,
> Quantum-ESPRESSO is an exceptional lab to make experience, since especially (but not only) for the easiest tasks (such as build the band structure of
> simple solids) many error messages are self-explanatory and user-friendly!  ;-)
> 
> Giovanni
> 
> 
> 
>> On 17 Dec 2019, at 10:25, Pooja Vyas <poojavyas1251995 at gmail.com <mailto:poojavyas1251995 at gmail.com>> wrote:
>> 
>> Following is my input file. I obtained the atomic position using X-CrysDen. But when I run the file it shows me an error message.
>> 
>> Input file:
>> &control
>>     calculation = 'scf',
>>     prefix = '9.1334'
>>     tstress= .true.
>>     tprnfor= .true.
>>     outdir = '/home/userpooja/cao.oct/'
>>     pseudo_dir = '/home/userpooja/cao.oct/pseudo/'
>>  /
>>  &system
>>     ibrav =  2,
>>     celldm(1) = 9.1334,
>>     nat =  27,
>>     ntyp = 2,
>>     ecutwfc = 100,
>> /
>> &electrons
>>     mixing_beta = 0.7
>>  /
>> 
>> ATOMIC_SPECIES
>> 
>> Ca 40.078  Ca.pbe-nsp-van.UPF
>> O 15.999 O.pbe-van_ak.UPF
>> 
>> ATOMIC_POSITIONS (alat)
>> Ca 0.5 0.5 0.0
>> Ca 0.0 0.0 0.0
>> Ca 0.5 0.0 0.5
>> Ca 0.0 0.5 0.5
>> O  0.0 0.0 0.5
>> O  0.5 0.5 0.5
>> O  0.0 0.5 0.0
>> O  0.5 0.0 0.0
>> Ca 0.5 0.5 1.0
>> Ca 0.0 0.0 1.0
>> O  0.0 0.5 1.0
>> O  0.5 0.0 1.0
>> Ca 0.0 1.0 0.0
>> Ca 0.5 1.0 0.5
>> O  0.0 1.0 0.5
>> O  0.5 1.0 0.0
>> Ca 0.0 1.0 1.0
>> O  0.5 1.0 1.0
>> Ca 1.0 0.0 0.0
>> Ca 1.0 0.5 0.5
>> O  1.0 0.0 0.5
>> O  1.0 0.5 0.0
>> Ca 1.0 0.0 1.0
>> O  1.0 0.5 1.0
>> Ca 1.0 1.0 0.0
>> O  1.0 1.0 0.5
>> Ca 1.0 1.0 1.0
>> K_POINTS (automatic)
>>   11 11 11 1 1 1
>> 
>> Error: 
>> 
>>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>>      task #        17
>>      from check_atoms : error #         1
>>      atoms #   1 and #   2 differ by lattice vector (-1, 1, 0) in crystal axis
>>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
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> -- 
> 
> Giovanni Cantele, PhD
> 
> CNR-SPIN
> c/o Dipartimento di Fisica
> Universita' di Napoli "Federico II"
> Complesso Universitario M. S. Angelo - Ed. 6
> Via Cintia, I-80126, Napoli, Italy
> 
> e-mail: giovanni.cantele at spin.cnr.it <mailto:giovanni.cantele at spin.cnr.it>
>             gcantele at gmail.com <mailto:gcantele at gmail.com>
> Phone: +39 081 676910
> Skype contact: giocan74
> Web page: https://sites.google.com/view/giovanni-cantele <https://sites.google.com/view/giovanni-cantele>
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
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-- 

Giovanni Cantele, PhD

CNR-SPIN
c/o Dipartimento di Fisica
Universita' di Napoli "Federico II"
Complesso Universitario M. S. Angelo - Ed. 6
Via Cintia, I-80126, Napoli, Italy

e-mail: giovanni.cantele at spin.cnr.it
            gcantele at gmail.com
Phone: +39 081 676910
Skype contact: giocan74
Web page: https://sites.google.com/view/giovanni-cantele

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