Quantitative detection of singlet O2 by cavity-enhanced absorption

Area of Science:

• Atomic and Molecular Physics
• Spectroscopy
• Quantum Chemistry

Background:

• Accurate measurement of single oxygen concentration is crucial for various scientific fields.
• Previous methods for determining absolute concentrations of singlet oxygen (a¹Δg) have limitations.
• The Noxon system (b¹Σg⁺ - a¹Δg) is important for understanding oxygen's electronic transitions.

Purpose of the Study:

• To develop a practical and sensitive method for determining the absolute concentration of singlet oxygen (a¹Δg).
• To present the first spectroscopic observation of the (1, 0) band of the b¹Σg⁺ - a¹Δg Noxon system.
• To determine the absolute transition probabilities for the b¹Σg⁺ - a¹Δg Noxon system using theoretical calculations.

Main Methods:

• Utilized sensitive off-axis integrated-cavity-output spectroscopy (ICOS).
• Employed narrowband, continuous-wave lasers within optical cavities for absorption measurements.
• Applied quantum chemistry theory to calculate absolute transition probabilities.

Main Results:

• Successfully demonstrated a practical method for absolute concentration determination of singlet oxygen (a¹Δg).
• Provided spectroscopic data confirming the initial observation of the (1, 0) band of the b¹Σg⁺ - a¹Δg Noxon system.
• Calculated precise absolute transition probabilities for the b¹Σg⁺ - a¹Δg Noxon system.

Conclusions:

• The developed off-axis ICOS method offers a sensitive approach for quantifying singlet oxygen.
• The study expands the understanding of oxygen's electronic spectroscopy with the observation of a new band.
• Quantum chemistry calculations provide essential data for the Noxon system, complementing experimental findings.