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==== Sample Hamiltonian (Atomo_i, struc.inp files) ====

Once we have the “CHARGES” we can produce the "Atomo_i" files by the
FIREBALL. “CHARGES” file has to be at the same directory when you are running
the FIREBALL. To the “fireball.in” we will write:

__&OPTION__ part

‐ nstepf = 1 \\
‐ ifixcharge = 1 \\

__&OUTPUT__ part

‐ iwrtatom = 1

Than you obtained “Atomo_i” files and the “struc.inp” file, which should be
modified to work properly when you run the STM simulation. How to do that:
The “struc.inp” file contains some information about the sample:

  50                                 ! number. of atoms in unit cell 
  1 45                              ! initial and final atom which is contributing to the tunneling current 
  12                                ! number maximum of neighbours 
  0.000000 0.000000 0.000000 1      ! coordinates and type of each atom 
  . 
  . 
  . 
  4                                 ! number of orbitals in each type of atom (in a row) 
  2                                 ! number of shells of each atom type (in a row) 
  0 1                               ! l of each shell type atom=1 (each atom type in a row) 
  16                                ! nkprl: no. of k's in one row (nk=nkprl2), =0 read a samplek.kpts file 
  1 1                               ! index_cell1, index_cell2 (ncell = (2*index_cell1+1)*(2*index_cell1+1)) 
  0.866025 , 0.5 , 0.               ! Horizontal lattice vector (x‐axis) 
  0.866025 , ‐0.5 , 0.              ! Horizontal lattice vector (y‐axis)

//!! We have to delete the last row of Lattice vector (the third one)//

The fixing the "nkprl" value to 0 and using the fireball k-points (with the
opposite to complete the Brouilloin) is strongly reccomended.
The "index_cell1" and "index_cell2" are relative to the number of cells we
need in each direction x and y to avoid the border problems. The product of them
gives us number of repetition unit which influence is involved to the
computation.

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