Revisiting the electron affinity of selenium.

Area of Science:

• Atomic Physics
• Quantum Chemistry
• Spectroscopy

Background:

• The electron affinity of atomic selenium (Se) has been a subject of experimental investigation.
• A previously accepted value from laser photodetachment microscopy (LPM) measurements in 2012 showed discrepancies with earlier data.
• This value served as the reference standard for over a decade despite the deviations.

Purpose of the Study:

• To re-examine and accurately determine the electron affinity of atomic selenium.
• To address the significant deviation observed in the previously accepted LPM measurement.
• To provide a more reliable EA(Se) value through an independent experimental method.

Main Methods:

• Utilized the slow-electron velocity-map imaging (SEVI) technique for high-resolution electron affinity measurements.
• Performed measurements on different isotopes of selenium to ensure accuracy.
• Analyzed the energy-level splitting of the neutral Se atom's 3P2-3P1 fine structure to validate the method.

Main Results:

• The SEVI method revealed a substantial deviation from the 2012 LPM result for the electron affinity of selenium.
• Measurements were verified for accuracy and robustness across different selenium isotopes.
• A revised electron affinity value for selenium (EA(Se)) was determined to be 16,297.78(4) cm-1.

Conclusions:

• The revised EA(Se) value is in excellent agreement with earlier laser photodetachment threshold experiments.
• The SEVI method provides a more accurate and reliable determination of selenium's electron affinity.
• This study corrects a long-standing reference value in atomic selenium research.