Isomeric [C3H4]+· ions: Their identification and generation in dissociative ionizations

Abstract The collisional activation (CA) and charge stripping (CS) mass spectra of the three [C 3 H 4 ] +· isomers, allene, propyne and cyclopropene, are reported. The extent of isomerization among these ions prior to collisional excitation depends on their internal energy content, but is small. Each [C 3 H 4 ] +· ion structure also can uniquely be generated via appropriate dissociative ionizations. Analysis of mixtures of [C 3 H 4 ] +· (daughter) ion structures is, in general, not possible from CA and CS mass spectra alone but may be aided by appearance energy measurements.