Direct evidence for the nature of core-level photoemission satellites using angle-resolved photoemission extended fine structure

Photoemission satellites from several systems have been found to exhibit exactly the same angle-resolved photoemission extended fine structure (ARPEFS) as found in the main peaks, when referred to the equivalent photoelectron wave number k for their own photoelectrons. This provides a direct and powerful method for experimentally determining the angular momentum parameters and the intrinsic/extrinsic nature of core-level photoemission satellites. We present ARPEFS satellite data for nitrogen 1s line in c(2 X 2) N-2/Ni(100), the nickel 3p line in clean nickel (111), the carbon 1s lines in (root 3 X root 3)R30 CO/Cu(111) and p2mg(2 X 1)CO/Ni(110), and the cobalt 1s line in p(1 X 1) Co/Cu(100). For the last two cases the "satellite" structure is actually the low-energy tail of a Doniach-Sunjic line shape. The satellite peaks and the tails of the Doniach-Sunjic line shapes exhibit ARPEFS curves that in all cases except one indicate angular-momentum parameters identical to the main peak and an Intrinsic nature. [S0163-1829(97)03648-5].