The lowest-energy spectator Auger band of the CH3F molecule observed via F and C 1s → σ* excitation

Resonant photoemission from the fluoromethane (CH3F) molecule has been measured with photon energies scanning through the resonance in which a C or F 1s electron is promoted to the lowest unoccupied molecular orbital σCF∗. The spectator Auger band with the lowest binding energy of ∼27 eV is tentatively assigned to 2e−26a1. The energy-resolved electron-ion coincidence experiments revealed that this state produces predominantly CH2+ ions both for C 1s and F 1s excitations, providing evidence that the spectator Auger decay to this state takes place within the molecular regime, where the valence electrons are delocalized over the entire molecule.