Zhai Hua-Jin, Wang Bin, Huang Xin, Wang Lai-Sheng
Department of Physics, Washington State University, 2710 University Drive, Richland, Washington 99354, USA.
J Phys Chem A. 2009 Sep 10;113(36):9804-13. doi: 10.1021/jp905478w.
We report a combined photoelectron spectroscopy (PES) and density functional theory (DFT) study on a series of tritantalum oxide clusters, Ta(3)O(n)(-). Well-resolved PES spectra are obtained for Ta(3)O(n)(-) (n = 1-8) at several detachment photon energies, yielding electronic structure information which is used for comparison with the DFT calculations. A trend of sequential oxidation is observed as a function of O content until Ta(3)O(8)(-), which is a stoichiometric cluster. Extensive DFT calculations are performed in search of the lowest energy structures for both the anions and neutrals. The first three O atoms are shown to successively occupy the bridging sites in the Ta(3) triangle. The next three O atoms each occupy a terminal site, with the seventh and eighth O atoms forming a double-bridge and a double-terminal, respectively. The Ta(3)O(7)(-) anion is found to possess a localized electron pair on a single Ta center, making it an interesting molecular model for Ta(3+) surface sites. Molecular orbital analyses are performed to elucidate the chemical bonding in the Ta(3)O(n)(-) clusters.
我们报道了一项关于一系列三钽氧化物簇Ta(3)O(n)(-)的光电子能谱（PES）和密度泛函理论（DFT）的联合研究。在几个 detachment 光子能量下获得了Ta(3)O(n)(-)（n = 1 - 8）的分辨率良好的PES光谱，产生了用于与DFT计算进行比较的电子结构信息。观察到随着O含量的变化存在连续氧化的趋势，直到Ta(3)O(8)(-)，它是一个化学计量簇。进行了广泛的DFT计算以寻找阴离子和中性分子的最低能量结构。前三个O原子依次占据Ta(3)三角形中的桥连位置。接下来的三个O原子各自占据一个末端位置，第七个和第八个O原子分别形成一个双桥和一个双末端。发现Ta(3)O(7)(-)阴离子在单个Ta中心上具有一个局域电子对，使其成为Ta(3+)表面位点的一个有趣的分子模型。进行了分子轨道分析以阐明Ta(3)O(n)(-)簇中的化学键。
