High-resolution photoelectron-Auger-electron coincidence study for the L₂₃–M₂₃M₂₃ transitions of argon

We report a high-resolution coincident experiment between the Ar 2p_1/2 and 2p_3/2 photoelectrons and subsequently emitted L₂₃–M₂₃M₂₃ Auger electrons, where the 2p photoelectrons were ionized far above the threshold. We demonstrate the applicability of the coincidence method when separating the different ionization and decay channels even in the case of strongly overlapping peaks. The measurement was carried out with a new high-energy-resolution electrostatic analyzer that is capable of recording the single and coincidence spectra at large range of emission angles simultaneously. An anomalous value was found for the 2P_3/2–(³P₀₁₂/¹D₂) intensity ratio in the ²p_3/2 coincidence spectrum, while all the other relative intensities are in good agreement with the previously published data. The possible reasons for the difference are discussed.