Exploring Iron's BCC Atomic Positions with Increasing Atom Numbers

If you want to know how to position 4 layers of atoms in a fcc lattice, you could for example do (in C++):// lattice constantfloat a = 2.863f;// position of the first atomfloat x,y,z;// loop over all atomsfor (int i=0; i<4; ++i) { // calculate the position of the atom (depending on its place in the lattice x = a * (i%2); y = a * ((i/2)%2); z = a * ((i/4)%2); // output the coordinates std::cout << "Fe " << x << " " << y << " "
  • #1
abode harry
5
0
how do i determine the different atomic positions of iron (bcc) as the number of atom increases.
 
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  • #2
What do you mean with "number of atom increases"? In solid iron, the atoms are always in a lattice. The lattice structure can depend on pressure and temperature (and the presence of other atoms), you can look it up in phase diagrams.
 
  • #3
thanks for the reply, but my question has not been answered .am trying to use quantum espresso to determine surface energy of iron.to do this, i need to increase the number of slab or layers. i need to know how to increase the atomic position, when increasing the layers.Please,i need someone to help me out
 
  • #4
Please use the "New Reply" button to reply, do not open new threads for replies. I merged your two threads.

So you are looking for coordinates of atoms in a bcc lattice? What is the orientation of the lattice in your coordinate system?
Do you know the lattice constant?
 
  • #5
the lattice constant for iron is 2.863 angstrom. orientation of the lattice, 100,010,001,111,110,101,011
 
  • #6
So you just have to add two layers (one for the "corners" one for the central atoms) each 2.863 angstrom?

To me, it is still unclear where exactly your problem is.

orientation of the lattice, 100,010,001,111,110,101,011
Which one?
 
  • #7
this is my input file. but my output is giving me error.overlap of 4 and 5

&control
calculation='scf'
restart_mode='from_scratch',
pseudo_dir = '/cygdrive/c/cygwin/espresso-4.2.1/pseudo/',
outdir='/home/ABODE HARRY/tmp/',
prefix='fe'
/
&system
ibrav = 3, celldm(1) =5.217, nat= 5, ntyp= 1,
ecutwfc = 40.0,ecutrho = 200.0,
report=1,
occupations='smearing', smearing='marzari-vanderbilt', degauss=0.05
noncolin = .true.
starting_magnetization(1) = 0.5
angle1(1) = 45.0
angle2(1) = 53.0
constrained_magnetization='total'
fixed_magnetization(1)=0.3,
fixed_magnetization(2)=0.4,
fixed_magnetization(3)=0.5,
lambda = 0.5
/
&electrons
conv_thr = 1.0e-9
mixing_beta = 0.3
/
ATOMIC_SPECIES
Fe 55.847 Fe.pz-nd-rrkjus.UPF
ATOMIC_POSITIONS
Fe 0.00 0.00 0.00
Fe 0.50 0.00 0.00
Fe 0.00 0.50 0.00
Fe 0.50 0.50 0.00
Fe 0.00 0.00 0.50
K_POINTS AUTOMATIC
4 4 4 1 1 1
 
  • #8
atomic position

this is my input file. but my output is giving me error.overlap of 4 and 5.i don't know if my coordinates are wrong.pls, could you help on how to determine the correct atomic positions

&control
calculation='scf'
restart_mode='from_scratch',
pseudo_dir = '/cygdrive/c/cygwin/espresso-4.2.1/pseudo/',
outdir='/home/ABODE HARRY/tmp/',
prefix='fe'
/
&system
ibrav = 3, celldm(1) =5.217, nat= 5, ntyp= 1,
ecutwfc = 40.0,ecutrho = 200.0,
report=1,
occupations='smearing', smearing='marzari-vanderbilt', degauss=0.05
noncolin = .true.
starting_magnetization(1) = 0.5
angle1(1) = 45.0
angle2(1) = 53.0
constrained_magnetization='total'
fixed_magnetization(1)=0.3,
fixed_magnetization(2)=0.4,
fixed_magnetization(3)=0.5,
lambda = 0.5
/
&electrons
conv_thr = 1.0e-9
mixing_beta = 0.3
/
ATOMIC_SPECIES
Fe 55.847 Fe.pz-nd-rrkjus.UPF
ATOMIC_POSITIONS
Fe 0.00 0.00 0.00
Fe 0.50 0.00 0.00
Fe 0.00 0.50 0.00
Fe 0.50 0.50 0.00
Fe 0.00 0.00 0.50
K_POINTS AUTOMATIC
4 4 4 1 1 1
 
  • #9
I have no idea how that config file works, so I don't see how I could help there.
 

1. What is the atomic structure of iron?

The atomic structure of iron consists of a nucleus containing 26 protons and typically 30-36 neutrons, surrounded by 26 electrons in energy levels or shells. The electrons are arranged in a specific pattern, with 2 in the first shell, 8 in the second shell, and 14 in the third shell, giving iron an electron configuration of [Ar] 3d6 4s2.

2. What is the atomic radius of iron?

The atomic radius of iron is approximately 126 picometers (pm), or 1.26 x 10-10 meters. This value can vary slightly depending on the oxidation state of iron and the specific crystal structure it is in.

3. How are the atomic positions of iron determined?

The atomic positions of iron are determined using techniques such as X-ray diffraction, neutron diffraction, and electron diffraction. These methods involve bombarding a sample of iron with a beam of particles or radiation and analyzing the resulting diffraction pattern to determine the positions of the atoms within the crystal lattice.

4. What is the significance of iron's atomic positions?

The atomic positions of iron are significant because they determine the physical and chemical properties of the element. For example, the arrangement of atoms in iron is responsible for its strength and ability to form alloys with other elements, making it a crucial element in the production of steel. Additionally, the positions of atoms can affect how iron interacts with other substances, such as oxygen, leading to various forms of iron oxide.

5. How do the atomic positions of iron change at different temperatures and pressures?

At different temperatures and pressures, the atomic positions of iron can change due to thermal expansion, phase transitions, and crystal structure transformations. For example, at high temperatures, iron can transition from its typical body-centered cubic (BCC) crystal structure to a face-centered cubic (FCC) structure, which can significantly affect its physical and chemical properties.

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