Molecular bromine dissociatively adsorbs to form a chemisorbed overlayer on Ni(100). The bromine induced 4px, y and 4pz orbitals have been identified at Γ̄ with binding energies of 6.6±0.2 eV and 5.3±0.2 eV below the Fermi energy, respectively. The relative ionization cross-section variations of the two bromine levels 4px and 4pz are observed to differ with changing photon energy.