Kinetic energy spectra of O − from dissociative electron attachment (DEA) to NO were measured at 7.6, 8.0, 9.0 and 10.0 eV electron energy using a spectrometer with hemispherical energy selectors for both the incident electrons and the resulting ions. The measurements were performed at 10 • , 30 • , 90 • and 135 • . The capacity of the spectrometer to detect both slow and fast ions was verified and the spectra were corrected for the analyser response function. Under these conditions only a

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... l corresponding to O − in the ground state and N in the first excited state was observed, a signal from the remaining two energetically accessible channels was absent. These observations confirm the original conclusion of Chantry (1968 Phys. Rev. 172 125) and reduce the range of possible explanations for the diametrically different observations of Orient and Chutjian (1995 Phys. Rev. Lett. 74 5017).