Dipole forbidden inner-shell excitation and decay of the N2 (1s)−1(2pπ) 3Πstate studied by electron impact experiments

The dipole forbidden inner-shell excitation of the N2 molecule to the (1s)−1(2pπ) 3Π state and its decay have been studied in an electron impact experiment at variable incident energy. The contribution of the dipole forbidden transitions to the N2 autoionization spectrum has been isolated via two different techniques. One is based on a subtraction procedure relying on non-coincidence measurements, while the other consists of an experiment where the electrons ejected in the decay process are detected in coincidence with scattered electrons which suffered an energy loss equal to the excitation energy of the (1s)−1(2pπ) 3Π state.