A VUV photoionization time-of-flight mass spectrometer for the formation, distribution, and reaction of nano-sized neutral metal oxide clusters

It is experimentally challenging to generate and detect nano-sized neutral metal oxide clusters with high-resolution mass spectrometry. Herein, a vacuum ultraviolet (VUV) photoionization time-of-flight (TOF) mass spectrometer based instrument has been home-made to study the generation, distribution, and reaction of nano-sized neutral metal oxide clusters. The VUV laser generation system has been designed to produce four 118 nm laser beams to ionize neutral metal oxide clusters in a supersonic beam with the “head-to-head” style. The TOF mass spectrometer is capable of analyzing nano-sized neutral metal oxide clusters with high mass resolution. Nano-sized neutral manganese oxide clusters Mn_mO_n (m = 5–58; n = 8–82) have been generated and the mass resolution (m/Δm) for Mn₄₁O₅₉ (∼1.3 nm) is about 7270. The association products Mn_mO_nC₂H₄ can be observed for the reaction of neutral manganese oxide clusters with C₂H₄. The rate constants for the reaction of (Mn₂O₃)_N (N = 2–22) with C₂H₄ have been experimentally determined.