Interaction Potential for NaCs for Ultracold Scattering and Spectroscopy

Area of Science:

• Atomic, Molecular, and Optical (AMO) Physics
• Quantum Chemistry
• Spectroscopy

Background:

• Accurate interatomic potentials are crucial for understanding and controlling ultracold molecules.
• Sodium-cesium (NaCs) is a promising system for ultracold molecule research due to its unique properties.

Purpose of the Study:

• To determine a precise interaction potential for NaCs molecules.
• To correlate experimental observations in ultracold spectroscopy and scattering with features of the interaction potential.

Main Methods:

• Fitting interaction potentials to experimental data from ultracold scattering and spectroscopy in optical tweezers.
• Utilizing Fourier transform spectroscopy to determine the central region of the potential.
• Employing coupled-channel calculations to analyze molecular states, binding energies, and wave functions.

Main Results:

• The long-range dispersion coefficient C6 was adjusted to 3256(1)Eh a0^6, a 0.9% increase, to match experimental findings.
• Established clear relationships between experimental observables and specific features of the NaCs interaction potential.
• Identified the molecular state responsible for the Feshbach resonance used in creating ultracold NaCs molecules.

Conclusions:

• The refined NaCs interaction potential accurately describes experimental data.
• Coupled-channel calculations using the final potential can predict bound-state energies and Feshbach resonance positions.
• This work provides a foundation for advanced studies and applications of ultracold NaCs molecules.