View source for Explanations for Si response input files

== Unit system ==

Hartree atomic units are used in this calculation by default.

== &calculation ==


  &calculation
    calc_mode = 'GS_RT'
  /

The variable <code>calc_mode</code> is set to be <code>'GS_RT'</code> mode, which corresponds to execute the ground state (GS) and real-time (RT) calculation  with single calculation task.

== &control ==


  &control
   sysname = 'Si'
  /

The variable <code>sysname</code> is set to be <code>'Si'</code>, which is used as the filename prefix of the outputs.



== &system ==



  &system
    iperiodic = 3
    al = 10.26d0,10.26d0,10.26d0
    isym = 8 
    crystal_structure = 'diamond'
    nstate = 32
    nelec = 32
    nelem = 1
    natom = 8
  /

<code>iperiodic = 3</code> indicates that three dimensional periodic boundary condition (bulk crystal) is assumed.
<code>al = 10.26d0, 10.26d0, 10.26d0</code> specifies the lattice constans of the unit cell crystaline.
The variable <code>isym</code> indicates the symmetry in the unit cell.
Considering the bulk silicon crystal with the applied electric field parallel to the one lattice axis, <code>  isym = 8 </code> is preferred to speed up the calculation.
For more infomation, see [[Symmetry group of crystaline]].
<code>crystal_structure = 'diamond'</code> indicate the crystal structure of the considered material.
<code>nstate = 32</code> indicates the number of Kohn-Sham orbitals to be solved. 
<code>nelec = 32</code> indicate the number of valence electrons in the system.
<code>nelem = 1</code> and <code>natom = 8</code> indicate the number of elements and the number of atoms in the system, respectively.

== &pseudo ==


  &pseudo
    iZatom(1)=14
    pseudo_file(1) = './Si_rps.dat'
    Lloc_ps(1)=2
  /

<code>iZatom(1) = 14</code> indicates the atomic number of the element 1.
<code>pseudo_file(1) = 'Si_rps.dat'</code> indicates the filename of the pseudopotential of element 1. 
<code>Lloc_ps(1) = 1</code> indicate the angular momentum of the pseudopotential that will be treated as local.


== &functional ==

  &functional
    xc ='TBmBJ'
    cval = 1d0
  /

<code>xc ='TBmBJ'</code> specifies the type of exchange correlation potential. The TBmBJ indicates a meta-generalized gradient approximation proposed by Tran and Blaha [https://doi.org/10.1103/PhysRevLett.102.226401  Phys. Rev. Lett. 102, 226401 (2009)].
<code>cval</code> specifies the additional parameter of the TBmBJ potential. In the case of the silicon, <code>cval = 1d0</code> is prefered to reproduce the experimentally mesured optical constants.