Selective formation of and by the reactions of nickel cluster cations with oxygen

The reactions of nickel cluster cations, Ni n + ( n = 2 – 29 ) , with O2 and their sequential reactions were studied using FT-ICR mass spectrometry. Reaction products were observed after 10−1–103 collisions with O2. The reaction probabilities of Ni n + ( n = 3 – 15 ) with O2 were almost unity while that of Ni 2 + was around 0.5. After 102–103 collisions with O2, the fully oxidized nickel clusters with the bulk nickel oxide composition (Ni/O = 1) were produced. However, the dominant products were two kinds of nickel suboxide clusters, Ni 13 O 8 + and Ni 16 O 10 + , which were inert in O2 under the present conditions.