Radiative Double-Electron Capture by Bare and One-Electron Ions on Gas Targets | JoVE Visualize

Area of Science:

Atomic and Molecular Physics
Quantum Electrodynamics
High-Energy Ion-Atom Collisions

Background:

Radiative double-electron capture (RDEC) is an atomic collision process analogous to the inverse of double photoionization.
Previous studies on RDEC have yielded mixed results, particularly when using solid targets like carbon foils, due to complications from multiple scattering.
Understanding RDEC is crucial for validating fundamental theories of quantum electrodynamics in atomic systems.

Purpose of the Study:

To conclusively demonstrate the existence of radiative double-electron capture (RDEC) in ion-atom collisions using gaseous targets.
To investigate RDEC for fluorine ions (F$^{9+}$ and F$^{8+}$) at 2.11 MeV/u impacting nitrogen (N$_{2}$) and neon (Ne) targets.
To compare experimental findings with theoretical predictions and previous experimental data obtained with different targets and projectile ions.

Main Methods:

Experimentally studied radiative double-electron capture (RDEC) using a beam of 2.11 MeV/u F$^{9+}$ and F$^{8+}$ ions.
Utilized gaseous targets of molecular nitrogen (N$_{2}$) and neon (Ne) to minimize complications from multiple scattering.
Analyzed collision data to identify and confirm the signature of RDEC, characterized by electron transfer and simultaneous photon emission.

Main Results:

Conclusively demonstrated the existence of radiative double-electron capture (RDEC) for both nitrogen and neon gas targets.
Observed RDEC in collisions involving F$^{9+}$ and F$^{8+}$ ions, providing new experimental data for this process.
Data for a carbon foil target showed some evidence of RDEC, but was complicated by multiple collisions affecting projectile charge states.

Conclusions:

Gaseous targets provide a cleaner environment for observing and studying radiative double-electron capture (RDEC) compared to solid targets.
The experimental results for RDEC in F$^{9+}$ and F$^{8+}$ collisions with N$_{2}$ and Ne align with theoretical expectations.
This study provides robust evidence for RDEC and contributes to a better understanding of electron correlation and quantum electrodynamics in atomic collisions.