This page describes how to calculate the density of states (DOS) using Fireball.
First, we need to obtain SCF-solution for particular geometry. Once we have it, we need to switch on these options:

  ifixcharge = 1  
  iwrtdos = 1

Simulation parameters are defined in two additional files:

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''dos.optional''
This file defines basic parameters of the DOS calculation.

       1.00000              ! ratio of lattice (for fractional coordinates, if xyz are in Angstroms maintain 1.000)
       1   60               ! natom_beg,natom_end (initial and final atom for the DOS calculation)
     151                    ! number of energies (number of energies in the DOS calcuation)
  -10.749617402457092 0.10  ! first energy (initial absolute energy (fireball's value is the Fermi Level) and energy step  
       0                    ! 1/0 yes/no write the tip_e_str.inp file for the DOS
      -4.00  4.00           ! minimun and maximum energy limit for writing the green function in the tip_e_str.inp file
       0.05                 ! imaginary part for the green function in the DOS calculation

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