The 2p shake-up spectrum of argon: effects of intermediate coupling

The monochromatised high-energy (hv=1487 eV) XPS spectrum of the Ar 2p shake-up satellite region is presented. A large number of new structures are discerned. Using theoretical calculations and deconvolution techniques it is shown that this spectrum should be assigned within an intermediate coupling scheme. From the calculations an approximate assignment of the 3p-np satellites can be made whereas the 3s-ns satellites are unambiguously identified. A number of double shake-up lines are also recorded for the first time.