Accurate Resonance-Parameter Approach to Transition-Metal Band Structure

The position $E_d$ and width $W$ of the $d$ resonance are shown to be good physical parameters, in that the same pair of parameters ($E_d=0.540\mathrm{}$, $W=0.088\mathrm{}$ Ry) is capable of reproducing Wood's band structure of fcc and bcc iron to within a rms error of 0.006 Ry. The energy levels were obtained by diagonalizing an improved hybrid nearly-free-electron tight-binding model Hamiltonian that includes explicitly the nonorthogonality of the basis functions.