Spin-exchange-induced circularly polarized molecular fluorescence.

Area of Science:

• Atomic and Molecular Physics
• Quantum Mechanics
• Chemical Physics

Background:

• Electron-molecule collisions are fundamental processes in physics and chemistry.
• Understanding spin dynamics in these collisions is crucial for various applications.
• Previous studies have lacked direct observation of spin transfer in electron-molecule interactions.

Purpose of the Study:

• To measure the circular polarization of light emitted from atomic hydrogen (H) and molecular hydrogen (H2).
• To investigate spin transfer during collisions of longitudinally polarized electrons with H2.
• To provide the first direct observation of spin transfer in electron-molecule collisions.

Main Methods:

• Bombarding molecular hydrogen (H2) with longitudinally polarized electrons.
• Measuring the circular polarization of emitted fluorescence from both atomic H and molecular H2.
• Analyzing the polarization near the energy threshold of the collisions.

Main Results:

• Observed significant circular polarization in emitted light from both atomic H and molecular H2.
• The measured circular polarization reached up to 10% of the incident electron polarization.
• Demonstrated a clear correlation between electron spin and emitted light polarization.

Conclusions:

• The study provides the first direct experimental evidence of spin transfer in electron-molecule collisions.
• The observed phenomenon opens new avenues for controlling spin in molecular systems.
• This finding has implications for understanding spin-dependent processes in chemistry and materials science.