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Abstract

Ionization and fragmentation processes of the NO molecule following the excitation of the nitrogen 1s electron have been studied by means of high-resolution mass-selective ionyield measurements. The yields of N + , O + and NO + ions acquired with a quadrupole mass spectrometer (QMS) and a linear time-of-flight spectrometer (TOF) show surprising differences at the N(1s −1 ) threshold region suggesting the selective attachment of the excited core electron to the N + centre during the dissociation of the NO + ion. The fragmentation branching ratios corrected for the angular and kinetic energy effects are presented. The kinetic energy distributions of the N + and O + fragments have been extracted for a number of Rydberg states manifesting a significant dependence on l quantum number and energy of the primary excited Rydberg level. The lifetime of the core-excited N(1s −1 ) state has been found from the shape of the low kinetic energy electron spectra acquired above the 1 and 3 thresholds.