Triplet Rydberg States of Aluminum Monofluoride

Area of Science:

• Molecular Spectroscopy
• Quantum Chemistry
• Laser Cooling

Background:

• Aluminum monofluoride (AlF) is a promising molecule for laser cooling and trapping.
• Accurate spectroscopic data is essential for developing laser cooling techniques.
• Previously, two predicted higher-lying triplet states of AlF remained experimentally uncharacterized.

Purpose of the Study:

• To experimentally identify and characterize the higher-lying triplet states of AlF.
• To confirm the predicted energetic ordering of these states.
• To investigate the interaction between the d³Π and e³Δ states and its effect on spectral properties.

Main Methods:

• High-resolution laser spectroscopy was employed to probe the electronic structure of AlF.
• Analysis of spectral transitions to identify and characterize the d³Π, e³Δ, and f³Σ⁺ states.
• Perturbation analysis, including spin-orbit and spin-rotation interactions, was used to understand spectral anomalies.

Main Results:

• The d³Π (v=0-6), e³Δ (v=0-2), and f³Σ⁺ (v=0-2) states of AlF were experimentally identified and characterized.
• The predicted energetic ordering of these triplet states was confirmed.
• Intensity borrowing and perturbations between the d³Π and e³Δ states were observed and analyzed, affecting rotational constants and internuclear distances.
• The ionization potential of AlF was determined to be 78,492(1) cm⁻¹ via ionization from the d³Π state.

Conclusions:

• The experimental characterization of the d³Π, e³Δ, and f³Σ⁺ states provides essential spectroscopic data for AlF.
• Understanding the interactions between these states refines molecular constants and internuclear distance calculations.
• The determined ionization potential is a key parameter for future AlF research and applications.