Mass Spectrometry Detection of Neutral Dissociative Fragments

摘要

The feasibility of detecting neutral fragments from molecular dissociative processes has been investigated using a mass spectrometer. The mass spectrometer is equipped with dual ionizers. One ionizer is used to form neutral and ionic dissociation fragments. The neutral fragments proceed to the second ionizer for ionization and subsequent detection. The difference in the measured signal when the first ionizer is on or off will reveal information on the formation of neutrals as a function of electron energy. This study concentrates on the detection of the neutral nitrogen (N) and hydrogen (H) fragments from molecular nitrogen (N2) and hydrogen (H2). No measurable experimental results from the two step, dissociation then ionization, process were obtained using the current experimental apparatus. The angular distribution of the dissociative fragments and the type and geometry of the apparatus prove to be important aspects which must be considered when detecting neutral fragments. Recommendations are given which may improve the possibility of detecting neutral fragments using this technique. (Author)