Infrared-Induced Reactivity of N2O on Small Gas-Phase Rhodium Clusters
Infrared-Induced Reactivity of N2O on Small Gas-Phase Rhodium Clusters
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DOI：
10.1021/jp201171p
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发表时间：
2011-03-31
影响因子：
2.9
通讯作者：
Mackenzie, Stuart R.
中科院分区：
文献类型：
--
作者：
Hamilton, Suzanne M.;Hopkins, W. Scott;Mackenzie, Stuart R.
本文用远红外和中红外多光子解离光谱研究了孤立的阳离子铑团簇与表面吸附的一氧化二氮RhnN_2O ~+（n = 4-8）的结构和表面反应性。使用氩原子标记方法记录的实验光谱与使用密度泛函理论（DFT）计算的那些的比较表明，一氧化二氮通过末端N-原子分子结合在铑除尘器上。结合被认为是专门发生在顶部网站与铑簇采用紧密堆积的结构。在相关的，但概念上不同的实验中，红外泵浦的振动模式对应的正常模式的吸附N2 O已被观察到导致N2 O部分的分解和氧化物簇的生产。除了n = 5之外，观察到所有研究的簇大小的簇表面化学。合理的N2 O分解机制给出了基于DFT计算使用交换相关泛函。在RhnON 2 O+络合物中泵送Rh-O伸缩的类似实验，在其上观察到相同的化学性质，证实了该反应的热性质。
Far- and mid-infrared multiple photon dissociation spectroscopy has been employed to study both the structure and surface reactivity of isolated cationic rhodium clusters with surface-adsorbed nitrous oxide, RhnN2O+ (n = 4-8). Comparison of experimental spectra recorded using the argon atom tagging method with those calculated using density functional theory (DFT) reveals that the nitrous oxide is molecularly bound on the rhodium duster via the terminal N-atom. Binding is thought to occur exclusively on atop sites with the rhodium clusters adopting close-packed structures. In related, but conceptually different experiments, infrared pumping of the vibrational modes corresponding with the normal modes of the adsorbed N2O has been observed to result in the decomposition of the N2O moiety and the production of oxide clusters. This cluster surface chemistry is observed for all cluster sizes studied except for n = 5. Plausible N2O decomposition mechanisms are given based on DFT calculations using exchange-correlation functionals. Similar experiments pumping the Rh-O stretch in RhnON2O+ complexes, on which the same chemistry is observed, confirm the thermal nature of this reaction.