Anderson Marie L, Lacz Agnieszka, Drewello Thomas, Derrick Peter J, Woodruff D Phil, Mackenzie Stuart R
Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom.
J Chem Phys. 2009 Feb 14;130(6):064305. doi: 10.1063/1.3075583.
Fourier transform ion cyclotron resonance mass spectrometry has been employed to study the reactions of gas-phase cationic cobalt clusters, Co(n) (+) (n=4-30), with nitric oxide, NO, and nitrous oxide, N(2)O, under single collision conditions. Isolation of the initial cluster permits detailed investigation of fragmentation channels which characterize the reactions of all but the largest clusters studied. In reaction with N(2)O, most clusters generate the monoxides Co(n)O(+) without fragmentation, cobalt atom loss accompanying only subsequent reactions. By contrast, chemisorption of even a single NO molecule is accompanied by fragmentation of the cluster. The measured rate coefficients for the Co(n) (+)+N(2)O reaction as a function of cluster size are significantly smaller than those calculated using the surface charge capture model, while for NO the rates are comparable. The reactions have been studied under high coverage conditions by storing clusters for extended periods to permit multiple reactions to occur. This leads to interesting chemistry on the surface of the cluster resulting in the formation of stable oxide clusters and/or the decomposition of nitric oxide on the cluster with the resulting loss of molecular nitrogen.
傅里叶变换离子回旋共振质谱已被用于研究气相阳离子钴簇Co(n)(+)(n = 4 - 30)在单碰撞条件下与一氧化氮(NO)和一氧化二氮(N₂O)的反应。对初始簇的分离使得能够详细研究碎裂通道，这些通道表征了除所研究的最大簇之外的所有簇的反应。在与N₂O的反应中，大多数簇生成了没有碎裂的单氧化物Co(n)O(+)，只有随后的反应才会伴随钴原子的损失。相比之下，即使单个NO分子的化学吸附也会伴随簇的碎裂。测量得到的Co(n)(+)+N₂O反应的速率系数作为簇大小的函数，明显小于使用表面电荷捕获模型计算得到的值，而对于NO，速率则相当。通过长时间存储簇以允许发生多次反应，在高覆盖条件下对反应进行了研究。这导致了簇表面上有趣的化学反应，从而形成稳定的氧化物簇和/或簇上一氧化氮的分解，导致分子氮的损失。
