Measurement of resonances in atomic oxygen by electron transmission spectroscopy

We present the first observations of resonant states in atomic oxygen using an electron-impact technique. We verify the existence of several doublet resonant states located previously by other techniques, and observe for the first time resonant states whose multiplicity is different from that of the ground state of O^-. To one such state located at 8.80 eV we assign the configuration [2p³(⁴S)3s²(⁴S)] and to another at 14.06 eV we assign the configuration [2p³(²D)3p²].