Dissociation of cyclopropane in double ionization continuum

Area of Science:

• Physical Chemistry
• Atomic and Molecular Physics
• Quantum Chemistry

Background:

• Cyclopropane is a fundamental cyclic hydrocarbon.
• Understanding its photoionization dynamics is crucial for molecular physics.
• Inner-valence ionization presents complex fragmentation pathways.

Purpose of the Study:

• To investigate the dissociative double photoionization of cyclopropane.
• To determine the energies of dication states and fragmentation pathways.
• To correlate experimental observations with theoretical calculations.

Main Methods:

• Utilizing tunable synchrotron radiation for inner-valence photoionization studies.
• Performing ab initio quantum chemical calculations for dication states and fragmentation.
• Comparing experimental appearance energies and kinetic energy release with theoretical predictions.

Main Results:

• Photon energy-dependent, state-selective dissociation observed in the 25-35 eV range.
• Cyclopropane ring deformation is selectively triggered at specific photon energies.
• Stepwise ionization populates dissociative states below the double-ionization threshold, while direct double ionization dominates above it.

Conclusions:

• Initial ring deformation dictates the population of dication states and subsequent dissociation channels.
• Jahn-Teller effects and ring-opening are significant below the double-ionization threshold.
• Franck-Condon region ionization populates specific electronic states above the threshold, influencing fragmentation.