Intrabeam Scattering for Ultracold Collisions.

Area of Science:

• Physical Chemistry
• Atomic Physics
• Molecular Collisions

Background:

• Probing cold and ultracold chemistry requires precise control over collision energies.
• Traditional methods often struggle with achieving narrow collision energy distributions.
• Single molecular beam techniques offer potential for controlled low-energy collisions.

Purpose of the Study:

• To demonstrate a new method for investigating cold and ultracold chemistry within a single molecular beam.
• To achieve precise control over relative velocities and collision energies between atomic species.
• To observe and characterize low-temperature collisions, specifically l-changing collisions.

Main Methods:

• Utilizing beam slippage to establish initial relative velocities in a single molecular beam.
• Implementing a dual-slit chopper for independent velocity control of different species.
• Achieving tunable collision energies in the millikelvin (mK) range with reduced spread.

Main Results:

• Demonstrated precise control over relative velocities (7-10 ± 1.1 m/s) and narrow angular divergence (<0.25°).
• Observed l-changing collisions between Xenon (Xe) Rydberg atoms and ground state Xe atoms at subKelvin temperatures.
• Achieved tunable collision energies between 200-450 mK with a root-mean-square deviation of approximately 18%.

Conclusions:

• The developed dual-slit chopper method provides effective control over collision energies in cold and ultracold regimes.
• This technique is applicable to various atomic and molecular species for studying low-temperature chemistry.
• The method facilitates straightforward access to even lower collision energies for future research.