Even-parity autoionizing states in neutral sodium (350-400 A).

Area of Science:

• Atomic Physics
• Quantum Mechanics
• Spectroscopy

Background:

• Autoionizing levels in atoms are crucial for understanding atomic structure and dynamics.
• Previous studies of sodium (Na I) autoionizing levels relied on ejected-electron spectroscopy.
• Accurate energy level data is essential for theoretical atomic physics models.

Purpose of the Study:

• To perform the first photoabsorption studies on specific even-parity autoionizing levels of Na I (2p(5)3s3p and 2p(5)3s4p).
• To compare newly obtained level values with existing data from ejected-electron spectroscopy.
• To confirm the identification of these autoionizing levels using theoretical calculations.

Main Methods:

• Utilized a recently developed laser-excitation technique for photoabsorption measurements.
• Employed ejected-electron spectroscopy of collisionally excited Na for comparative analysis.
• Performed ab initio calculations to support the identification of observed energy levels.

Main Results:

• Successfully measured photoabsorption spectra for the even-parity 2p(5)3s3p and 2p(5)3s4p autoionizing levels of Na I.
• Observed level values show good agreement with previously reported data where applicable.
• Ab initio calculations provide strong confirmation for the identified energy levels.

Conclusions:

• The new laser-excitation photoabsorption technique is effective for studying atomic autoionizing levels.
• The study validates and refines the understanding of Na I autoionizing level energies.
• Combined experimental and theoretical approaches enhance confidence in atomic level assignments.