DIRECT EVIDENCE FOR THE NATURE OF CORE-LEVEL PHOTOEMISSION SATELLITESUSING ANGLE-RESOLVED PHOTOEMISSION EXTENDED FINE-STRUCTURE

Photoemission satellites from several systems have been found to exhib it exactly the same angle-resolved photoemission extended fine structu re (ARPEFS) as found in the main peaks, when referred to the equivalen t photoelectron wave number k for their own photoelectrons. This provi des a direct and powerful method for experimentally determining the an gular momentum parameters and the intrinsic/extrinsic nature of core-l evel photoemission satellites. We present ARPEFS satellite data for ni trogen 1s line in c(2 X 2) N-2/Ni(100), the nickel 3p line in clean ni ckel (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 lo w-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 identica l to the main peak and an Intrinsic nature. [S0163-1829(97)03648-5].