[QE-users] ibrav (QE)

[sally issa]

 I try to calculate the density of state of Nb which is stable in centered 
cubic. To do this I use ibrav = 0 and identify the cell_parameter. but with 
ibrav = 0 I get a number of electrons from the shell d = 7 electrons (instead 
of 10).

I tried to do this with ibrav = 3 which is good for the centered cuubic (well 
defined in pw.x quantum espresso) and I remove the cell_parameter of course. I 
get a good number of electrons at the level of the layer d.

so I would like to know please what is the difference at the level of ibrav = 0 
and ibrav = 3 which affects the result of the number of electron. SEEN that if 
you put the input of ibrav = 0 or that of ibrav = 3 on xcrysden it gives you a 
well-formed centered cubic structure.

Thank you

Sally ISSA
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Re: [QE-users] ibrav (QE)

[sally issa]

Thank you for your answer. No they are not the same, you fint here in 
attachement that when i use ibrav=0 and I define the cell parameter for sur, I 
find this fillings with this same range of x.
Thank you
Sally ISSA

From: users  on behalf of Lorenzo 
Paulatto 
Sent: 03 March 2021 15:14
To: Quantum ESPRESSO users Forum 
Subject: Re: [QE-users] ibrav (QE)

They look pretty much the same to me, except being plot with a different range 
along x

--
Lorenzo Paulatto - Paris
On Mar 3 2021, at 1:55 pm, sally issa  wrote:


 I try to calculate the density of state of Nb which is stable in centered 
cubic. To do this I use ibrav = 0 and identify the cell_parameter. but with 
ibrav = 0 I get a number of electrons from the shell d = 7 electrons (instead 
of 10).

I tried to do this with ibrav = 3 which is good for the centered cuubic (well 
defined in pw.x quantum espresso) and I remove the cell_parameter of course. I 
get a good number of electrons at the level of the layer d.

so I would like to know please what is the difference at the level of ibrav = 0 
and ibrav = 3 which affects the result of the number of electron. SEEN that if 
you put the input of ibrav = 0 or that of ibrav = 3 on xcrysden it gives you a 
well-formed centered cubic structure.

Thank you

Sally ISSA
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Re: [QE-users] ibrav (QE)

[sally issa]

Also with ibrav=0 for a centred cubic structure, I used 2 atoms (0 0 0) and 
(0.5 0.5 0.5). On the other hand, with ibrav=3 for cc structure I use a single 
atom (0 0 0) and I saw my structure on xcrysden ... its well built so I didn't 
understand why with ibrav=0 the filling of d shell is bad.


From: users  on behalf of Paolo 
Giannozzi 
Sent: 03 March 2021 15:51
To: Quantum ESPRESSO users Forum 
Subject: Re: [QE-users] ibrav (QE)

Please plot them with the same x and y ranges and dimensions.

On Wed, Mar 3, 2021 at 2:34 PM sally issa 
mailto:sally.is...@outlook.com>> wrote:

Thank you for your answer. No they are not the same, you fint here in 
attachement that when i use ibrav=0 and I define the cell parameter for sur, I 
find this fillings with this same range of x.
Thank you
Sally ISSA

From: users 
mailto:users-boun...@lists.quantum-espresso.org>>
 on behalf of Lorenzo Paulatto mailto:paul...@gmail.com>>
Sent: 03 March 2021 15:14
To: Quantum ESPRESSO users Forum 
mailto:users@lists.quantum-espresso.org>>
Subject: Re: [QE-users] ibrav (QE)

They look pretty much the same to me, except being plot with a different range 
along x

--
Lorenzo Paulatto - Paris
On Mar 3 2021, at 1:55 pm, sally issa 
mailto:sally.is...@outlook.com>> wrote:


 I try to calculate the density of state of Nb which is stable in centered 
cubic. To do this I use ibrav = 0 and identify the cell_parameter. but with 
ibrav = 0 I get a number of electrons from the shell d = 7 electrons (instead 
of 10).

I tried to do this with ibrav = 3 which is good for the centered cuubic (well 
defined in pw.x quantum espresso) and I remove the cell_parameter of course. I 
get a good number of electrons at the level of the layer d.

so I would like to know please what is the difference at the level of ibrav = 0 
and ibrav = 3 which affects the result of the number of electron. SEEN that if 
you put the input of ibrav = 0 or that of ibrav = 3 on xcrysden it gives you a 
well-formed centered cubic structure.

Thank you

Sally ISSA
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222

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Re: [QE-users] Error in scf calculation of large number of atoms

[sally issa]

I have the same calcul with 128 atoms, sometimes it appears this error but I 
change the K mesh or the periodic condition are not good one.
What you use for k point?

On 4 Mar 2021, at 09:57, Pooja Vyas  wrote:


Dear users,
I have an input script (scf1.in attached below) of CaO with 2 
atoms. It runs fine for scf calculation.
I want to compute the energy of CaO with 64 atoms. So I opened 
scf1.in file in XCrysden so it displayed 27 atoms and then I 
followed the below steps:
1) Display->Unit of repetition -> translational asymmetric unit
2) Above step reduced 27 atoms to 4 Ca and 4 O atoms totalling 8.
3) Then I followed Modify->number of units drawn and selected 2,2,2 in it. So, 
it displayed 8 atoms*(2*2*2)= 64 atoms.

I took these atomic positions and made the file scf2.in 
attached below. But on running that script for scf calculation, it shows me the 
following error:

 %%
 task # 1
 from check_atoms : error # 1
 atoms #   1 and #   2 differ by lattice vector (-1, 1, 0) in crystal axis
 %%

The error is due to overlapping of atoms. But can anyone let me know how I can 
compute the energy of 64 atoms? How do I figure out the equivalent atomic 
positions which causes this error?




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[QE-users] Prefix.save

[sally issa]

Dear users,
I try to calculate the density of state (DOS) but sometimes I find that the wfc 
files are not located inside prefix.save folder.
But I find that wfc files are generated outside with prefix.mix
That is correctly detected by QE or no?
thank you in advance
Sally ISSA

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Re: [QE-users] Why is my VC-RELAX not showing converged result?

[sally issa]

Hey!
I suggest you to put in section:

etot_conv_thr =1.d-4 # this one for convergence threshold on total energy for 
ionic minimization
forc_conv_thr=1.d-3 #the same thing but convergence threshold on forces

U can put also in section

Conv_thr = 1.0e-6
Mixing_beta=0.2
Mixing_mode = “plain”
Mixing_ndim=8

U can check your cell_parameters… its not seems to me that is body cubic center!

Try it and tell me …
Best regards,
Sally

On 19 Feb 2022, at 17:59, Naharin Jannath  wrote:


I ran the VC-RELAX for simple niobium until I get a converged value. But at the 
bottom of the output, the cell parameter stops changing. Also, the pressure is 
well below the "pres_conv_thr" which was set to 0.01 in the input file. Can 
anyone tell me how to fix it? Also, my CELL_PARAMETER vs K curve is not smooth 
even using large smearing.

calculation = 'vc-relax'
restart_mode = 'from_scratch'
prefix = 'Nb'
etot_conv_thr = 0.01
pseudo_dir = '.'
outdir = '.'
disk_io = 'none'
tstress = .true.
tprnfor = .true.
/

degauss = 0.05
ecutrho = 360
ecutwfc = 45
ibrav = 0
nat = 1
ntyp = 1
occupations = "smearing"
smearing = "gaussian"
/

conv_thr = 1.0e-08
electron_maxstep = 200
mixing_mode = 'plain'
mixing_beta = 0.5
startingpot = "atomic"
startingwfc = "atomic+random"
/

ion_dynamics = "bfgs"
/

cell_dynamics = "bfgs"
press_conv_thr = 0.01
/
ATOMIC_SPECIES
Nb 92.90638 Nb.pbe-spn-kjpaw_psl.0.3.0.UPF
ATOMIC_POSITIONS {crystal}
Nb 0.00 0.00 0.00
CELL_PARAMETERS {angstrom}
1.675751271 1.675751271 1.675751271
-1.675751271 1.675751271 1.675751271
-1.675751271 -1.675751271 1.675751271
K_POINTS {automatic}
10 10 10 0 0 0
output --
PRESSURE -
total stress (Ry/bohr**3) (kbar) P= -47.02
total stress (Ry/bohr**3) (kbar) P= -9.58
total stress (Ry/bohr**3) (kbar) P= 0.65
total stress (Ry/bohr**3) (kbar) P= 0.02
total stress (Ry/bohr**3) (kbar) P= 0.01
total stress (Ry/bohr**3) (kbar) P= -0.21
CELL_PARAMETERS (angstrom)
1.662361144 1.662361144 1.662361144
--
CELL_PARAMETERS (angstrom)
1.659001159 1.659001159 1.659001159
--
CELL_PARAMETERS (angstrom)
1.659212618 1.659212618 1.659212618
--
CELL_PARAMETERS (angstrom)
1.659217666 1.659217666 1.659217666
--
CELL_PARAMETERS (angstrom)
1.659217666 1.659217666 1.659217666
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[QE-users] Temperature effect

[sally issa]

Hello, 

I want to study the effect of temperature on the mechanical properties pure 
metal element and metallic alloy like elastic constant, energy formation of 
defects … 
I have been calculated it at the ground state at 0K.
Can anyone suggest me which expression of Q.E. need to do this calculation 
please?

Best regards, 
Sally

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Re: [QE-users] users Digest, Vol 175, Issue 20

[sally issa]

Hello, 
Do you try with cell_parameters 
Cubic (P) ? 

 1.675751271  0.   0.
0.1.675751271  0.
0.0.1.675751271
 

Or you want cubic (I)?
Usually the number of k points grid is related to the size of the box you are 
working with.
In your case you are working with one atom, so you don’t care if you increase 
or decrease it! 

I have already performed a calculation with vc-relax for Niobium in a centred 
cubic cell, I used 2 atoms per cell. 
Why do you use only one? 

Sally

> On 20 Feb 2022, at 20:53, Naharin Jannath  
> wrote:
> 
>  1.675751271
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Re: [QE-users] Medium-entropy materials

[sally issa]

Hi,
I am calculating the medium entropy alloy (NbTiZr) with QE with 54 atoms and 
more.
I use etot_conv= 1.d-4 and force_conv=1.d-3, conv_thr=1.0e-6 and 
mixing_beta=0.7, degauss=0.015
U can try if you want!
But I relax my system, the last iteration is scf and I obtain a good 
convergence!
Best regards,
Sally

On 18 Jul 2022, at 15:46, Connor Wilson  wrote:


Hi everyone,

I am trying to obtain a converged SCF calculation (using Quantum ESPRESSO, 
version 7.0) for the medium-entropy oxide (CoCuMgZn)0.25 O. This material 
crystalizes in the rocksalt structure. I am using a 64-atom supercell. I have 
attached my input file at the end of this message.

My problem is: after 50 iterations, my calculations show no trend towards 
convergence (ie. the 'estimated scf accuracies' in the pw.x output file 
stabilize around 0.5 Ry). I have made the following adjustments in an effort to 
achieve better convergence:

  *   using degauss values of 0.001, 0.01, 0.02
  *   using a 6 x 6 x 6 K-mesh
  *   using mixing_beta of 0.05, 0.1, 0.2
  *   using ecutwfc of 60, 70, 100 (each with 10x ecutrho)
  *   using PBEsol, PBE pseudopotentials

My question is: do you think it is possible to achieve a converged SCF 
calculation using QE? If it is, what might an appropriate value of conv_thr be, 
and could you suggest other changes to my input file I could try?

Thank you for your time,


Connor Wilson
Brock University
Department of Mathematics and Science
1812 Sir Issac Brock Way, St. Catharines, ON, CAN, L2S 3A1






 pw.x input ###


  calculation = 'scf',
  prefix = 'MEO',
  tstress = .true.,
  tprnfor = .true.,
  restart_mode = 'from_scratch',
  outdir = '/home/cw279/projects/def-crandles/cw279/MEO/222c/alat'
  pseudo_dir = '/home/cw279/pseudo',
/


  ibrav = 1,
  celldm(1) = 15.1,
  nat = 64,
  ntyp = 5,
  ecutwfc = 100,
  ecutrho = 1000,
  occupations = 'smearing',
  smearing = 'mv',
  degauss = 0.01,
/


  electron_maxstep = 50,
  mixing_beta = 0.1,
  conv_thr  = 1.0d-6,
  mixing_mode = 'local-TF',
  mixing_ndim = 10,
/

ATOMIC_SPECIES
  Mg  24.305   Mg.pbe-spnl-kjpaw_psl.1.0.0.UPF
  O   15.9994  O.pbe-n-kjpaw_psl.1.0.0.UPF
  Zn  65.380   Zn.pbe-dnl-kjpaw_psl.1.0.0.UPF
  Ni  58.6934  Ni.pbe-spn-kjpaw_psl.1.0.0.UPF
  Co  58.9332  Co.pbe-spn-kjpaw_psl.0.3.1.UPF

K_POINTS {automatic}
  4 4 4  0 0 0

ATOMIC_POSITIONS {crystal}


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[QE-users] Orthorhombic unit cell

[sally issa]

Good morning all,

Is there anyone have worked with orthorhombic cell?
I want to define the unit cell for orthorhombic with 4 atoms:(0,y,1/4),(0,-y, 
3/4), (1/2, y+1/2, 1/4) and (-1/2, -y+1/2, 3/4).
With wyckoff position (4c).
I don’t have idea how define y.
Do you have suggestions ?

Thank you
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