!cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
! bands-empty-FCC-lattice.f90
! calculate the first bands along the Gamma - X=(2*pigr/a)(100) direction
! units are 2\hbar^2\pigr^2 / (ma^2)
!cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
program bands
implicit none
integer :: n1, n2, n3, i, steps=50, m=1
real :: x,e
open (unit=1, file='bands.dat')

kpoints: do i= 0,steps
x = float(i)/steps

do n3 = -m,m
do n2 = -m,m
do n1 = -m,m
e = x**2 + 2*x*(n1+n2-n3) + (-n1+n2+n3)**2 + (n1-n2+n3)**2 + (n1+n2-n3)**2
write(1,*)i,e
end do
end do
end do

end do kpoints
close (1)

end program bands