Multielectron coincidence spectroscopy of the Ar2+(2p-2) double-core-hole decay

The dominant decay pathways of argon 2p-2 double-core-hole states have been investigated using synchrotron radiation and a magnetic-bottle-type spectrometer coupled with an ion time-of-flight spectrometer. This experiment allows for efficient multi-electron-ion coincidence measurements, and thus for following the Auger cascade step by step in detail. Dominant decay pathways leading to Ar4+ final states via Ar3+ intermediate states have been assigned with the help of theoretical ab initio calculations. The weak correlated decay of the two core holes by emission of a single Auger electron, leading to Ar3+ final states, has been observed at 458.5-eV kinetic energy. Compared to the total decay of the 2p-2 double core vacancies, this two-electron-one-electron process was measured to have a branching ratio of 1.9 x 10-3 & PLUSMN; 1.0 x 10-3. Furthermore, the remaining decay paths of the Ar1+ (1s-1) core hole to higher charge states and their respective contributions to the total yield have been analyzed and show very good agreement with theoretical results.

Automated summary

The dominant decay pathways of argon 2p-2 double-core-hole states were investigated using synchrotron radiation and a magnetic-bottle-type spectrometer coupled with an ion time-of-flight spectrometer. The experiment allowed for efficient multi-electron-ion coincidence measurements to track the Auger cascade step by step. The decay pathways leading to Ar4+ final states via Ar3+ intermediate states were assigned using theoretical ab initio calculations.