Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK.
J Phys Chem A. 2011 Mar 31;115(12):2489-97. doi: 10.1021/jp201171p. Epub 2011 Mar 10.
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, Rh(n)N(2)O(+) (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 cluster 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 N(2)O has been observed to result in the decomposition of the N(2)O moiety and the production of oxide clusters. This cluster surface chemistry is observed for all cluster sizes studied except for n = 5. Plausible N(2)O decomposition mechanisms are given based on DFT calculations using exchange-correlation functionals. Similar experiments pumping the Rh-O stretch in Rh(n)ON(2)O(+) complexes, on which the same chemistry is observed, confirm the thermal nature of this reaction.
远-中和中红外多光子解离光谱学已被用于研究孤立的阳离子铑簇与表面吸附的一氧化二氮的结构和表面反应，Rh(n)N(2)O(+) (n = 4-8)。使用氩原子标记法记录的实验光谱与使用密度泛函理论 (DFT) 计算的光谱进行比较，结果表明一氧化二氮通过末端 N 原子与铑簇分子结合。据认为，结合仅发生在顶位上，铑簇采用密堆积结构。在相关但概念上不同的实验中，观察到与吸附的 N(2)O 的振动模式对应的红外泵浦导致 N(2)O 部分的分解和氧化物簇的生成。这种簇表面化学被观察到所有研究的簇尺寸，除了 n = 5。基于 DFT 计算使用交换相关泛函，给出了合理的 N(2)O 分解机制。对 Rh(n)ON(2)O(+) 配合物中 Rh-O 伸缩振动进行类似的泵浦实验，观察到相同的化学性质，证实了该反应的热性质。
