We have observed significant differences in the fragmentation patterns of isomeric Polycyclic Aromatic Hydrocarbon (PAH) cations following collisions with helium atoms at center-of-mass energies around 100 eV. This is in contrast to the situation at other collision energies or in photo-absorption experiments where isomeric effects are very weak and where the lowest-energy dissociation channels (H- and C2H2-loss) dominate in statistical fragmentation processes. In the 100 eV range, non-statistical fragmentation also competes and is uniquely linked to losses of single carbon atoms (CHx-losses). We find that such CHx-losses are correlated with the ionic ground state energy within a given group of isomers. We present results for three C16H10+, four C18H12+ and five C20H12+ isomers colliding with He.
Stockett, M. H., Gatchell, M., De Ruette, N., Giacomozzi, L., Chen, T., Rousseau, P., … Cederquist, H. (2015). Isomer effects in fragmentation of Polycyclic Aromatic Hydrocarbons. International Journal of Mass Spectrometry, 392, 58–62. https://doi.org/10.1016/j.ijms.2015.09.005