In Situ Observation of Nonpolar to Strongly Polar Atom-Ion Collision Dynamics

Area of Science:

• Atomic, Molecular, and Optical Physics
• Quantum Chemistry
• Chemical Physics

Background:

• Rydberg atoms possess large electron orbitals, making them highly sensitive to external fields.
• Collisions involving Rydberg atoms can access complex multi-channel dynamics.
• Stark states, induced by electric fields, significantly alter Rydberg atom interactions.

Purpose of the Study:

• To investigate the collision dynamics between ions and Rydberg atoms in a multi-channel regime.
• To understand the influence of Stark state coupling on collision timescales.
• To explore the temperature dependence of ion-Rydberg atom collision dynamics.

Main Methods:

• Experimental preparation of ion-Rydberg atom collision pairs using dipole selection rules.
• In-situ observation of collision dynamics across a range of temperatures (k_{B}μK to k_{B}K).
• Semiclassical simulations to model pair state evolution and nonadiabatic dynamics.

Main Results:

• Observed separation of collisional timescales due to differing spatial gradients of interaction potentials.
• Demonstrated counterintuitive temperature dependence: colder systems exhibit faster collision dynamics.
• Controlled preparation of collision pairs on nonpolar potentials, influencing channel occupation.

Conclusions:

• Coupling between nonpolar and polar Stark states creates complex collision dynamics.
• Nonadiabatic dynamics are tunable and play a crucial role in ion-Rydberg atom interactions.
• The observed temperature dependence offers new insights into controlling quantum collisional processes.