Vibrationally resolved decay width of interatomic Coulombic decay in HeNe

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Chemical Physics

Background:

• The study of photoionization in van der Waals clusters provides insights into electron correlation and interatomic interactions.
• Resonant photoionization mechanisms are crucial for understanding molecular excitation and fragmentation pathways.

Purpose of the Study:

• To experimentally verify the two-center resonant photoionization mechanism in HeNe dimers.
• To investigate the electronic and vibrational state-resolved decay dynamics of interatomic Coulombic decay (ICD) in HeNe.

Main Methods:

• Photoionization spectroscopy of HeNe dimers was performed.
• Ion yield was measured as a function of photon energy across the He 1s3p excitation and He ionization threshold.
• Vibrational and electronic state-resolved decay widths were determined from the observed spectral features.

Main Results:

• A significant enhancement (factor of >60) in HeNe+ ion yield was observed when the He atom's excitation resonantly couples to the radiation field.
• Experimental evidence supporting the predicted two-center resonant photoionization mechanism was obtained.
• Interatomic Coulombic decay (ICD) lifetimes were resolved for different electronic and vibrational states of the HeNe dimer.
• A strong positive correlation between ICD lifetime and vibrational state was identified.

Conclusions:

• The experimental results confirm the theoretical prediction of a two-center resonant photoionization mechanism in HeNe.
• The study provides detailed insights into the state-resolved dynamics of interatomic Coulombic decay in van der Waals systems.
• The observed dependence of ICD lifetime on vibrational excitation highlights the role of nuclear motion in decay processes.