The double minimum E(3)¹Σ_u⁺ state in Cs₂

Area of Science:

• Atomic and Molecular Physics
• Spectroscopy
• Quantum Chemistry

Background:

• The electronic structure of diatomic molecules is fundamental to understanding chemical bonding and molecular behavior.
• Caesium dimer (Cs2) exhibits complex electronic states, including those with double minima, which are challenging to characterize.
• Understanding these states is crucial for applications in quantum information and laser cooling.

Purpose of the Study:

• To investigate the double minimum E¹Σ_u⁺ state in caesium dimer.
• To construct an accurate potential energy curve for this state.
• To analyze the implications of limited data on the outer well of the potential curve.

Main Methods:

• Analysis of rotationally resolved spectra from the E¹Σ_u⁺← X¹Σ_g⁺ band system.
• Application of polarization labeling techniques to simplify spectral analysis.
• Utilizing the Fourier grid Hamiltonian and inverted perturbation approach for potential curve construction.

Main Results:

• Identification of 6727 rotationally resolved transitions within the E¹Σ_u⁺ state.
• Construction of a potential energy curve accurately reproducing observed energy levels in the inner well and above the barrier.
• Observation of spectral features indicating a double minimum potential.

Conclusions:

• The study provides a detailed characterization of the double minimum E¹Σ_u⁺ state in caesium dimer.
• The constructed potential energy curve offers insights into the molecule's electronic structure.
• Further experimental data on the outer well is needed for a complete potential energy surface description.