subject:"\[QE\-users\] ibrav number check"

Re: [QE-users] ibrav number check

2018-11-20 Thread Yunzhe Wang

The atomic positions you gave are not precise enough. Some symmetrical 
equivalent positions are determined as asymmetrical since internally, only 
positions matched up to 10^-5 are considered as equivalent.

As you can imagine, if you put a basis with lower symmetry, then some 
symmetries of the lattice will be broken.

Best,
Yunzhe Wang
Mueller Research Group,
Johns Hopkins University


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From: users  on behalf of Giovanni 
Cantele 
Sent: Monday, November 19, 2018 5:02 PM
To: Quantum Espresso users Forum
Subject: Re: [QE-users] ibrav number check

maybe you’re visualising the conventional, rather than the primitive unit cell.
Try to set Display -> Primitive Cell Mode

The bct unit cel should show up.

Giovanni

--

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.cant...@spin.cnr.it<mailto:giovanni.cant...@spin.cnr.it>
gcant...@gmail.com<mailto:gcant...@gmail.com>
Phone: +39 081 676910
Skype contact: giocan74
Web page: https://sites.google.com/view/giovanni-cantele

On 19 Nov 2018, at 19:38, Chan, Edmund 
mailto:thc...@exeter.ac.uk>> wrote:

Dear all users,

I am currently trying to relax a methylammonium lead iodide CH3NH3PbI3 
structure which has tetragonal structure I4/mcm. Thus, in my input file, I 
select ibrav = 7 (body centred teragonal). However, as I visualise the input 
and output on Xcrysden, the unit cell becomes orthorhombic. Why is that?



   title = 'MAPI' ,
 calculation = 'relax' ,
restart_mode = 'from_scratch' ,
  outdir = './' ,
  pseudo_dir = './' ,
  prefix = 'CH3NH3PbI3' ,
/

   ibrav = 7,
   A = 8.83920,
   C = 12.6948,
 nat = 12,
ntyp = 5,
 ecutwfc = 80 ,
   ecutrho = 800,
/

electron_maxstep = 5000 ,
conv_thr = 1.0d-6 ,
 mixing_beta = 0.3 ,
/

ion_dynamics = 'bfgs' ,
/
ATOMIC_SPECIES
C   12.01070  c_pbesol_v1.2.uspp.F.UPF
H1.00794  H.pbesol-rrkjus_psl.0.1.UPF
N   14.00670  N.pbesol-theos.UPF
   Pb  207.2  Pb.pbesol-dn-kjpaw_psl.0.2.2.UPF
I  126.90450  i_pbesol_v1.uspp.F.UPF
ATOMIC_POSITIONS alat
   Pb  0.00.00.5
I  0.00.00.25000
I  0.294200.205800.5
I -0.29420   -0.207600.5
C  0.544000.921000.78400
H  0.609201.002100.76990
H  0.557300.845500.72460
H  0.551500.875200.86430
N  0.389000.987000.76700
H  0.324700.913900.73030
H  0.381401.068100.73430
H  0.339300.990800.83100
K_POINTS automatic
  1 1 1   0 0 0

Thank you all.


Kind regards,

Edmund Chan

Edmund Chan
PhD Renewable Energy Student
Environment & Sustainablity Institute
College of Engineering, Mathematics and Physical Sciences
University of Exeter, Penryn Campus
Penryn, Cornwall
United Kingdom
TR10 9FE

Tel: +44 (0)7455 235 701
Email: thc...@exeter.ac.uk<mailto:thc...@exeter.ac.uk>
LinkedIn: https://uk.linkedin.com/in/edmundchan1




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Re: [QE-users] ibrav number check

2018-11-19 Thread Giovanni Cantele

maybe you’re visualising the conventional, rather than the primitive unit cell.
Try to set Display -> Primitive Cell Mode

The bct unit cel should show up.

Giovanni

-- 

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.cant...@spin.cnr.it
gcant...@gmail.com
Phone: +39 081 676910
Skype contact: giocan74
Web page: https://sites.google.com/view/giovanni-cantele

> On 19 Nov 2018, at 19:38, Chan, Edmund  wrote:
> 
> Dear all users,
>  
> I am currently trying to relax a methylammonium lead iodide CH3NH3PbI3 
> structure which has tetragonal structure I4/mcm. Thus, in my input file, I 
> select ibrav = 7 (body centred teragonal). However, as I visualise the input 
> and output on Xcrysden, the unit cell becomes orthorhombic. Why is that?
>  
>  
> 
>title = 'MAPI' ,
>  calculation = 'relax' ,
> restart_mode = 'from_scratch' ,
>   outdir = './' ,
>   pseudo_dir = './' ,
>   prefix = 'CH3NH3PbI3' ,
> /
> 
>ibrav = 7,
>A = 8.83920,
>C = 12.6948,
>  nat = 12,
> ntyp = 5,
>  ecutwfc = 80 ,
>ecutrho = 800,
> /
> 
> electron_maxstep = 5000 ,
> conv_thr = 1.0d-6 ,
>  mixing_beta = 0.3 ,
> /
> 
> ion_dynamics = 'bfgs' ,
> /
> ATOMIC_SPECIES
> C   12.01070  c_pbesol_v1.2.uspp.F.UPF
> H1.00794  H.pbesol-rrkjus_psl.0.1.UPF
> N   14.00670  N.pbesol-theos.UPF
>Pb  207.2  Pb.pbesol-dn-kjpaw_psl.0.2.2.UPF
> I  126.90450  i_pbesol_v1.uspp.F.UPF
> ATOMIC_POSITIONS alat
>Pb  0.00.00.5   
> I  0.00.00.25000   
> I  0.294200.205800.5   
> I -0.29420   -0.207600.5   
> C  0.544000.921000.78400   
> H  0.609201.002100.76990   
> H  0.557300.845500.72460   
> H  0.551500.875200.86430   
> N  0.389000.987000.76700   
> H  0.324700.913900.73030   
> H  0.381401.068100.73430   
> H  0.339300.990800.83100   
> K_POINTS automatic
>   1 1 1   0 0 0
>  
> Thank you all.
>  
>  
> Kind regards,
>  
> Edmund Chan
> 
> Edmund Chan
> PhD Renewable Energy Student
> Environment & Sustainablity Institute
> College of Engineering, Mathematics and Physical Sciences
> University of Exeter, Penryn Campus
> Penryn, Cornwall
> United Kingdom
> TR10 9FE
> 
> Tel: +44 (0)7455 235 701 
> Email: thc...@exeter.ac.uk 
> LinkedIn: https://uk.linkedin.com/in/edmundchan1 
> 
> 
>  
> 
>  
> ___
> users mailing list
> users@lists.quantum-espresso.org 
> https://lists.quantum-espresso.org/mailman/listinfo/users 
> 
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[QE-users] ibrav number check

2018-11-19 Thread Chan, Edmund

Dear all users,

I am currently trying to relax a methylammonium lead iodide CH3NH3PbI3 
structure which has tetragonal structure I4/mcm. Thus, in my input file, I 
select ibrav = 7 (body centred teragonal). However, as I visualise the input 
and output on Xcrysden, the unit cell becomes orthorhombic. Why is that?



   title = 'MAPI' ,
 calculation = 'relax' ,
restart_mode = 'from_scratch' ,
  outdir = './' ,
  pseudo_dir = './' ,
  prefix = 'CH3NH3PbI3' ,
/

   ibrav = 7,
   A = 8.83920,
   C = 12.6948,
 nat = 12,
ntyp = 5,
 ecutwfc = 80 ,
   ecutrho = 800,
/

electron_maxstep = 5000 ,
conv_thr = 1.0d-6 ,
 mixing_beta = 0.3 ,
/

ion_dynamics = 'bfgs' ,
/
ATOMIC_SPECIES
C   12.01070  c_pbesol_v1.2.uspp.F.UPF
H1.00794  H.pbesol-rrkjus_psl.0.1.UPF
N   14.00670  N.pbesol-theos.UPF
   Pb  207.2  Pb.pbesol-dn-kjpaw_psl.0.2.2.UPF
I  126.90450  i_pbesol_v1.uspp.F.UPF
ATOMIC_POSITIONS alat
   Pb  0.00.00.5
I  0.00.00.25000
I  0.294200.205800.5
I -0.29420   -0.207600.5
C  0.544000.921000.78400
H  0.609201.002100.76990
H  0.557300.845500.72460
H  0.551500.875200.86430
N  0.389000.987000.76700
H  0.324700.913900.73030
H  0.381401.068100.73430
H  0.339300.990800.83100
K_POINTS automatic
  1 1 1   0 0 0

Thank you all.


Kind regards,

Edmund Chan

Edmund Chan
PhD Renewable Energy Student
Environment & Sustainablity Institute
College of Engineering, Mathematics and Physical Sciences
University of Exeter, Penryn Campus
Penryn, Cornwall
United Kingdom
TR10 9FE

Tel: +44 (0)7455 235 701
Email: thc...@exeter.ac.uk
LinkedIn: https://uk.linkedin.com/in/edmundchan1
[uoe]

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Re: [QE-users] ibrav number check

Re: [QE-users] ibrav number check

[QE-users] ibrav number check

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