Negative-ion mass spectrometric study of ion pair formation in the vacuum ultraviolet. I. N2O→O−+N+2

Negative ion formation from N2O has been studied using synchrotron radiation in the 15–40 eV photon energy range. Only O− ion signal is observed by mass spectrometry. The onset of the photodissociation efficiency curve for O− from N2O is in good agreement with the thermochemical threshold of 15.79 eV for the formation of O−(2Pu)+N+2(X̃ 2∑+g). Several series of peaks are identified as resulting from predissociation from the Rydberg states converging to N2O+(Ã 2∑+, B̃ 2∏, and C̃ 2∑+). In particular, two Rydberg series (ndσ and ndπ) converging to the C̃ state are observed most prominently.