X-ray photoemission spectra of core levels in Ni metal

The x-ray photoemission spectrum of a core level in Ni metal is calculated and compared to experimental results. The model is based upon a local interaction of the $3d$ bands with the core hole. The strength of the interaction U is taken to be 4 eV, which gives a satellite binding energy approximately 6 eV greater than that of the main line. The Ni band structure is described by a linear combination of atomic orbitals method, and hybridization of the $3d$ bands with the 4s-4p bands is included. The resulting spectrum is a convolution of single-band spectra (one for each 3d↓ orbital: xy, yz, etc.). Comparison of our essentially exact numerical results to asymptotic theory is made.