[QE-users] Problem with the order of introducing atoms

[Fariba Nazari]

​Hi,
What a bout the Cell Parameters?
Regards
Fariba
IASBS

On Sat, 22/09/2018 10:35 AM, Mohammad Alidoosti <m.alidoosti at gmail.com> wrote:
> 
Dear all
> 


> 
I am doing the  SCF calculations of hexagonal InSe using QE 6.2.1, which consist of four atoms (2In+2Se). When I changed the order of introducing atoms in the atomic position block in my input file, I saw that the number of selected k-points in the output changed from 52 to 14. That is, the code can find the symmetry group in one case but no symmetry in the other case. Is it important the order of introducing atoms!!!!! while I have done the same calculations for both of them. It should be noted that I got the same problem in other versions of QE such as 5.4 and 6.3. In the following, you can find the input files.
The first case :

&control
    calculation="scf"
    restart_mode="from_scratch",
    prefix='Inse',
    pseudo_dir = '/home/pseudo',
    outdir='./tmp'
 /
 &system
    ibrav=  0, nat= 4, ntyp= 2,
    ecutwfc =80,
 /
 &electrons
    conv_thr =  1.0d-6 
    mixing_beta = 0.6
/
ATOMIC_SPECIES
In  114.818  In.pbe-hgh.UPF 
Se  78.96    Se.pbe-hgh.UPF
ATOMIC_POSITIONS (crystal)
  Se      0.33332800000000   0.66666100000000   0.06148300000000  
  Se      0.33332800000000   0.66666100000000   0.27424600000000  
  In      0.66666200000000   0.33332900000000   0.11202500000000  
  In      0.66666200000000   0.33332900000000   0.22371100000000 
CELL_PARAMETERS (angstrom)
   2.04502258622038  -3.54208302195961   0.00000000000000
   2.04502258622038   3.54208302195961   0.00000000000000
   0.00000000000000   0.00000000000000  25.00000000076542
K_POINTS {automatic} 
 10 10 1  0 0 0

> 
###############################################

> 
In the second case, ATOMIC_POSITIONS should be changed to :
ATOMIC_POSITIONS (crystal)
  In      0.66666200000000   0.33332900000000   0.11202500000000  
  In      0.66666200000000   0.33332900000000   0.22371100000000 
  Se      0.33332800000000   0.66666100000000   0.06148300000000  
  Se      0.33332800000000   0.66666100000000   0.27424600000000  

> 

> 
Thanks in advance.


-- 
> 







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> School of Nano-Science
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> 
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