Three-electron interatomic Coulombic decay from the inner-valence double-vacancy states in NeAr

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Chemical Physics

Background:

• Interatomic Coulombic decay (ICD) is a fundamental process where an excited atom or molecule transfers energy to a neighboring atom or molecule, leading to electron emission.
• Previous studies have primarily focused on ICD involving one or two electrons.
• Understanding ICD mechanisms is crucial for interpreting photoionization and relaxation processes in atomic and molecular systems.

Purpose of the Study:

• To unambiguously identify and characterize three-electron interatomic Coulombic decay (3e-ICD) in the NeAr system.
• To investigate the dynamics and kinetics of this novel 3e-ICD process.
• To compare the rate of 3e-ICD with other competing relaxation pathways.

Main Methods:

• Utilized momentum-resolved electron-ion multicoincidence spectroscopy.
• Initiated the decay from the Ne 1s(-2) inner-valence double-vacancy state in a NeAr dimer.
• Analyzed the emitted electrons and ions to reconstruct the decay pathway and energetics.

Main Results:

• Unambiguously identified 3e-ICD in NeAr, originating from the Ne 1s(-2) state.
• Observed the population of Ne(+)(2p(-1))-Ar(2+)(3p(-2)) outer-valence triple-vacancy states.
• Determined that 3e-ICD is significantly faster than fluorescence decay and charge transfer via curve crossing.

Conclusions:

• The first experimental evidence for 3e-ICD has been established.
• The 3e-ICD process in NeAr is a rapid and dominant relaxation channel.
• This finding opens new avenues for studying complex electron correlation effects in molecular systems.