#  Na6Si34 clathrate (equivalent to Na24Si136 )
#  optimization of the unit cell, DOS, and DOS-p



kptopt 1           # Option for the automatic generation of k points,
                   # taking into account the symmetry
#ngkpt  14 14 14   
ngkpt  2 2 2   

prtden  1          # Print the density, for later use 
toldfe  1.0d-6

nband   100         # increase nband to 100 or more for DOS, DOSp, or band

occopt  3         # only for metals - fractional occupation of electron bands 
tsmear  0.01      # and a sear factor

#Optimization of the lattice parameters. Make sure to comment-out these lines
#for DOS and DOS-partial runs

# optcell 1
# ionmov  3
# ntime  10
# dilatmx 1.15
# ecutsm  0.5

# DOS and DOS-partial  section - uncomment these lines for DOS calculation 

prtdos 2               
dosdeltae  0.0007      # energy step is approx. 0.02 eV
                         
#prtdos 3
#dosdeltae  0.0007
#natsph 3
#iatsph 1 2 3
#ratsph 2.5


#Definition of the unit cell
acell 3*27.6278        # a = 14.62 Angstroms  
rprim  0.0  0.5  0.5   # FCC primitive vectors (to be scaled by acell)
       0.5  0.0  0.5   
       0.5  0.5  0.0

#Definition of the atom types
ntypat 2          # Number of atom types
znucl 11 14       # Atomic numbers 
                  # possible type(s) of atom. The pseudopotential(s) 
                  # mentioned in the "files" file must correspond
                  # to the type(s) of atom. 
                         

#Definition of the atoms
natom 40          
typat                    # there are 6 Na and 34 Si atoms 
1 1 1 1 1 1
2 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2 2
2 2 2 2
 
xred              # This keyword indicate that the location of the atoms
                  # will follow, one triplet of number for each atom
     0.0000   0.0000   0.0000   
     0.3750   0.3750   0.3750   
     0.0000   0.5000   0.0000   
     0.0000   0.0000   0.5000   
     0.6250   0.6250   0.6250   
     0.5000   0.0000   0.0000   
     0.1250   0.1250   0.1250   
     0.7810   0.7810   0.7810   
     0.7810   0.7810   0.1570   
     0.6290   0.6290   0.0050   
     0.6290   0.6290   0.2370   
     0.9950   0.7630   0.3710   
     0.8750   0.8750   0.8750    
     0.2190   0.2190   0.2190    
     0.1570   0.7810   0.7810    
     0.7810   0.1570   0.7810    
     0.2190   0.2190   0.8430    
     0.2190   0.8430   0.2190    
     0.8430   0.2190   0.2190    
     0.0050   0.6290   0.6290    
     0.6290   0.0050   0.6290    
     0.3710   0.3710   0.9950    
     0.3710   0.9950   0.3710    
     0.9950   0.3710   0.3710    
     0.2370   0.6290   0.6290    
     0.6290   0.2370   0.6290    
     0.3710   0.3710   0.7630    
     0.3710   0.7630   0.3710    
     0.7630   0.3710   0.3710    
     0.3710   0.9950   0.7630    
     0.7630   0.3710   0.9950    
     0.2370   0.0050   0.6290    
     0.0050   0.6290   0.2370    
     0.6290   0.2370   0.0050    
     0.0050   0.2370   0.6290    
     0.6290   0.0050   0.2370    
     0.2370   0.6290   0.0050    
     0.7630   0.9950   0.3710    
     0.9950   0.3710   0.7630    
     0.3710   0.7630   0.9950    



#Definition of the planewave basis set
ecut 15.0         # Maximal kinetic energy cut-off, in Hartree

#Definition of the SCF procedure
nstep 30          # Maximal number of SCF cycles
diemac 12.0       # Although this is not mandatory, it is worth to
                  # precondition the SCF cycle. The model dielectric
                  # function used as the standard preconditioner
                  # is described in the "dielng" input variable section.
                  # Here, we follow the prescription for bulk silicon.