Threshold photoelectron spectrum of the CH₂OO Criegee intermediate

Area of Science:

• Atmospheric Chemistry
• Spectroscopy
• Quantum Chemistry

Background:

• Criegee intermediates are key species in alkene ozonolysis.
• Understanding their properties is vital for atmospheric models.
• The simplest Criegee intermediate, CH2OO, serves as a fundamental model system.

Purpose of the Study:

• To experimentally determine the adiabatic ionization energy of CH2OO.
• To provide a benchmark for theoretical calculations on Criegee intermediates.
• To enhance the understanding of atmospheric reaction mechanisms involving Criegee species.

Main Methods:

• Photoelectron spectroscopy was employed.
• Measurements were conducted near the first ionization energy threshold.
• Experimental data was compared with theoretical predictions.

Main Results:

• The adiabatic ionization energy of CH2OO was experimentally determined.
• The results serve as a validation point for theoretical models.
• This study establishes a benchmark for future investigations of larger Criegee intermediates.

Conclusions:

• The experimental ionization energy of CH2OO is now established.
• This work refines our understanding of Criegee intermediate energetics.
• Accurate theoretical data for larger Criegee intermediates can be developed based on this benchmark.