Plasma environmental effect on Auger electron spectroscopy of an ion embedded in a dense plasma

The characteristic kinetic energies of electrons emitted in Auger decay processes of inner-vacancy states carries valuable information of the element and its chemical environment in atoms, molecules, clusters, liquids, and solids. Thus, Auger electron spectroscopy (AES) is widely used as an important experimental tool in both fundamental and applied research. In a dense plasma environment, however, the kinetic energies of Auger electrons are significantly modified and therefore AES shows new features compared with that of the isolated species. Here, we theoretically investigated the AES of K- and $2p$-vacancy states for different charge states of iron ions embedded in dense plasma. It is found that the kinetic energy of the Auger electron is evidently shifted toward higher energy compared with the isolated ion; The higher the mass density and ionization stage, the larger shift the kinetic energy of the Auger electron. The shift of kinetic energy of the Auger electron is also weakly temperature dependent with a lower shift at a higher temperature of the plasma. The Auger widths of the $2p$-vacancy states are more evidently affected by the plasma environment than the K-vacancy states, especially at a higher plasma density. The findings of the present work are helpful for the study of Auger processes and radiative properties in dense plasmas such as astrophysical plasmas in the interior of stars and laboratory plasmas produced in interaction of x-ray free-electron lasers with solids, liquids, nanoplasmas, and clusters.