Autoionization mediated by electron transfer.

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Cluster Science

Background:

• Photoionization of van der Waals clusters is a key process for understanding electron dynamics.
• Electron transfer mediated decay (ETMD) is a theoretically predicted autoionization mechanism in multi-atom systems.
• Experimental observation of ETMD in mixed clusters has been challenging.

Purpose of the Study:

• To experimentally investigate electron-electron coincidence spectra of argon-krypton (Ar-Kr) clusters after photoionization.
• To identify and characterize novel autoionization mechanisms in mixed van der Waals clusters.
• To provide experimental evidence for theoretically predicted ETMD processes.

Main Methods:

• Photoionization of Ar-Kr clusters was performed.
• Electron-electron coincidence spectroscopy was employed to measure kinetic energies of emitted electrons.
• Analysis of coincidence spectra to identify specific decay pathways and final states.

Main Results:

• Coincidence spectra revealed an electron with 0-1 eV kinetic energy in conjunction with an Ar 3s cluster photoelectron.
• This low-energy electron is attributed to a final state of Ar + Kr+ + Kr+.
• The observed process is identified as electron transfer mediated decay (ETMD).

Conclusions:

• The study provides the first experimental observation of electron transfer mediated decay (ETMD) in a mixed Ar-Kr van der Waals cluster.
• This mechanism involves a concerted transition across three atoms, confirming theoretical predictions.
• The findings advance the understanding of complex autoionization processes in atomic clusters.