[QE-users] Structure with symmetry

[Giovanni Cantele]

Here, a list of the ibrav values that you can choose
https://www.quantum-espresso.org/Doc/INPUT_PW.html#idm200 <https://www.quantum-espresso.org/Doc/INPUT_PW.html#idm200>

It seems that you have a simple orthorhombic lattice, that should correspond to ibrav = 8.
Than you can specify the variables
a
b
c
as crystal axes lengths in Angstrom units.

Giovanni


> On 18 Mar 2021, at 10:03, Offermans Willem <willem.offermans at vito.be> wrote:
> 
> 
> Dear Quantum Espresso friends,
> 
> In most of my calculations, I’m dealing with metallic slabs, representing
> surfaces, derived from fcc metals, such as (221) or (533).
> 
> In these calculations, I’m dealing with structures with symmetry.
> The single symmetry element is an inversion center. S_2 is the Schönfließ symbol,
> if I recall correctly. 
> 
> In the output file of pw.x, I encounter the following note:
> 
> <snip>
> ...
>      Message from routine setup:
>      using ibrav=0 with symmetry is DISCOURAGED, use correct ibrav instead
> …
> </snip>
> 
> The unitcell is defined as:
> 
> <snip>
> ...
>      celldm(1)=  10.627880  celldm(2)=   0.000000  celldm(3)=   0.000000
>      celldm(4)=   0.000000  celldm(5)=   0.000000  celldm(6)=   0.000000
> 
>      crystal axes: (cart. coord. in units of alat)
>                a(1) = (   1.000000   0.000000   0.000000 )  
>                a(2) = (   0.000000   1.500000   0.000000 )  
>                a(3) = (   0.000000   0.000000   4.596194 )  
> …
> </snip>
> 
> I would like to follow the advice to use the correct ibrav, but I need some help
> to determine the correct ibrav. 
> 
> Can someone help me to determine the correct Ibrav?
> 
> 
> 
> 
> 
> Met vriendelijke groeten,
> Mit freundlichen Grüßen,
> With kind regards,
> 
> 
> Willem Offermans
> Researcher Electrocatalysis SCT
> VITO NV | Boeretang 200 | 2400 Mol
> Phone:+32(0)14335263 Mobile:+32(0)492182073 
> 
> Willem.Offermans at Vito.be <mailto:Willem.Offermans at Vito.be>
> <vito.jpg>
> 
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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
Phone: +39 081 676910
Skype contact: giocan74

ResearcherID: http://www.researcherid.com/rid/A-1951-2009
Web page: https://sites.google.com/view/giovanni-cantele/home

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