New electron-ion coincidence setup: Fragmentation of acetonitrile following N 1s core excitation

A new electron-energy-resolved electron-ion coincidence setup was developed based on the Scienta SES-100 hemispherical electron analyzer and a Wiley-McLaren type ion TOF spectrometer. With this setup, an electron-ion coincidence study of gas-phase acetonitrile (CH3CN) was performed using synchrotron radiation. The fragmentation patterns in coincidence with resonant Auger electrons were recorded, following N 1s core excitations to the molecular orbital of the πCN∗ character. Also the dissociation of doubly charged molecular ions produced after normal Auger decay of N 1s−1 core-hole states was investigated from PEPICO and PEPIPICO maps. Kinetic energy releases in some reactions were determined with the aid of Monte-Carlo modelling.