Dissociative Photoionization of Diethyl Ether

Area of Science:

• Physical Chemistry
• Chemical Physics
• Mass Spectrometry

Background:

• Diethyl ether (Et2O) ion fragmentation is crucial for understanding chemical processes.
• Previous studies lacked detailed analysis of specific dissociation channels and energy dependencies.

Purpose of the Study:

• To investigate the dissociative photoionization of internal energy selected diethyl ether ions.
• To determine appearance energies and analyze dissociation mechanisms.
• To model fragmentation pathways using statistical theory.

Main Methods:

• Imaging photoelectron photoion coincidence (IPPC) spectroscopy was employed.
• Diethyl ether ions (Et2O+) were selected based on internal energy.
• Dissociative photoionization channels were analyzed over a 5 eV range.

Main Results:

• Two parallel and three sequential dissociative photoionization channels were identified for Et2O+.
• Appearance energies for H-loss (m/z=73) and methyl-loss (m/z=59) ions were determined at 10.419 ± 0.015 eV and 10.484 ± 0.008 eV.
• Transition-state switching and a reverse barrier of 325 meV for a secondary fragment (m/z=45) were observed.

Conclusions:

• Statistical theory accurately models the observed dissociative photoionization pathways.
• The findings provide insights into ion fragmentation dynamics and energy landscapes.
• The statistical model can predict ion abundances for combustion diagnostics.