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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Neutral tantalum-Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study
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Neutral tantalum-Carbide Clusters: A Multiphoton Ionization and Density Functional Theory Study

机译：中性碳化钽簇：多光子电离和密度泛函理论研究

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摘要

Neutral tantalum-carbide clusters, Ta_mC_n (m = 1 - 6, n = 1 - 7), have been formed in a supersonic expansion following the reaction of tantalum and acetylene in a laser ablation source. These clusters have been subjected to multiphoton ionization at 532 and 355 nm and the mass spectra recorded in a reflectron time-of-flight mass spectrometer. The cluster distributions show a drop off after m = 4 suggesting the stabilization of clusters containing four tantalum atoms. We have investigated the structures of these clusters using density functional theory and shown that the smaller clusters tend to form fragments of face-centered cubes, culminating in the formation of a distorted cube of stoichiometry Ta_4C_4. The structure of Ta_4C_4 is shown to be a distorted tetrahedron, or "butterfly", made up of four tantalum atoms with a carbon atom bonded to each face. The theoretical calculations also indicate that clusters containing three tantalum atoms form a triangle and that there is competition for the carbon atoms to bond to either the face or the edge of the tantalum triangle.
机译：钽和乙炔在激光烧蚀源中的反应后，在超音速膨胀中形成了中性碳化钽簇Ta_mC_n（m = 1-6，n = 1-7）。这些簇已在532和355 nm处进行了多光子电离，质谱记录在反射式飞行时间质谱仪中。在m = 4之后，团簇分布出现下降，表明含有四个钽原子的团簇稳定。我们使用密度泛函理论研究了这些团簇的结构，结果表明，较小的团簇倾向于形成面心立方体的碎片，最终形成了化学计量Ta_4C_4扭曲的立方体。 Ta_4C_4的结构显示为扭曲的四面体或“蝴蝶”，由四个钽原子组成，每个原子上都有一个碳原子。理论计算还表明，包含三个钽原子的簇形成一个三角形，并且存在碳原子与钽三角形的表面或边缘键合的竞争。

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