Non-resonant multiphoton ionization of small cyclic molecules: a comparison of fragmentation pathways for ethylene sulfide, ethylene oxide, propylene oxide and cyclopropane

We report non-resonant multiphoton ionization time-of-flight mass spectra for ethylene sulfide (thiirane), ethylene oxide, propylene oxide and cyclopropane for 355 nm excitation over a wide range of laser pulse energies. The fragmentation pathways are laser energy independent for energies greater than approximately 5 mJ pulse−1. The results indicate that the major fragmentation patterns are molecule specific and cannot be generalized for the analogous ring systems. The fragmentation mechanism is discussed separately for each molecule.