Photoelectron satellite spectrum in the region of the3sCooper minimum of argon

The 3s,3p satellite spectrum of argon has been studied with use of synchrotron radiation in the 40–70-eV energy range. In the region of the 3s Cooper minimum (42.5 eV±0.2), the integral intensity of the satellites is ten times larger than the 3s partial cross section. The angular asymmetry parameters have been measured as a function of the photoelectron energy for the 3s ${}^2$S,3p ${}^2$P final states as well as for the satellites. For the lowest photon energies it appears that the β parameter values of the most intense satellites are strongly dependent on the total angular momentum of the final ionic state.