Cu atoms and clusters on regular and defect sites of the SiO2 surface. Electronic structure and properties from first principle calculations
Cu atoms and clusters on regular and defect sites of the SiO2 surface. Electronic structure and properties from first principle calculations
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SiO2 表面规则和缺陷位点上的 Cu 原子和簇。
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
F. Illas
中科院分区：
文献类型：
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作者：
G. Pacchioni;N. López;F. Illas
用团簇模型密度泛函方法研究了孤立的Cu原子和Cu ~（2+）~（5+）团簇与二氧化硅表面脱羟基的相互作用.规则的、无缺陷的表面对Cu原子表现出非常低的反应性;结合主要是由于极化机制。这意味着撞击的Cu原子将容易在表面上扩散并重新蒸发，除非被捕获在缺陷部位。实际上，Cu原子和团簇以及SiO2表面的一些典型的点缺陷之间形成了强键。我们分析了其中的两个缺陷，非桥氧位（NBO）3Si-O·和对应于Si单占据s悬挂键的E′中心3Si·.与这些顺磁中心相互作用的Cu簇显着扰动的界面处的键合，所示的不同的几何结构相比，气相簇的支持。一些可观察到的后果的集群沉积，特别是在差距的材料中的状态的外观，进行了讨论。
The interaction of isolated Cu atoms and small Cu clusters, from Cu2 to Cu5, with the dehydroxylated surface of silica has been investigated by means of cluster models density functional calculations. The regular, non defective, surface shows very low reactivity towards Cu atoms; the binding is largely due to polarization mechanisms. This implies that impinging Cu atoms will easily diffuse on the surface and re-evaporate unless trapped at a defect site. In fact, strong bonds are formed between Cu atoms and clusters and some typical point defects at the SiO2 surface. We have analyzed two of these defects, the non-bridging oxygen site (NBO), 3Si–O•, and the E′ center corresponding to a Si singly occupied s dangling bond, 3Si•. The Cu clusters interacting with these paramagnetic centers are significantly perturbed by the bonding at the interface, as shown by the different geometrical structures of supported compared to gas-phase clusters. Some observable consequences of the cluster deposition, in particular the appearance of states in the gap of the material, are discussed.