Anisotropy and kinetic energy release in ionic fragmentation of molecules photoexcited to inner-shell hole states

Abstract

Angular distributions of fragment ions produced from linear molecules photoexcited to inner‐shell excited states reflect symmetry of these excited states because the production of the ions is very fast compared to the rotational motion of the molecules. Some examples have been shown for the π* state, Rydberg orbital excited states and the shape resonance of diatomic and linear triatomic molecules using a rotatable time‐of‐flight mass spectrometer and monochromatized synchrotron radiation. Kinetic energy distributions of fragment ions from inner‐shell hole states have been determined at several photon energies using time‐of‐flight spectra and a simulation fitting calculation. These distributions give a considerable difference between neutral excited and ionized states, indicating that the dissociation pathway from the π* excited state is different from that at the ionized state.