Averkiev Boris B, Boldyrev Alexander I, Li Xi, Wang Lai-Sheng
Utah State University, Department of Chemistry and Biochemistry, Logan, Utah 84322-0300, USA.
J Phys Chem A. 2007 Jan 11;111(1):34-41. doi: 10.1021/jp066747e.
The electronic and geometrical structure of a nitrogen-doped Al6- cluster (Al6N-) is investigated using photoelectron spectroscopy and ab initio calculations. Photoelectron spectra of Al6N- have been obtained at three photon energies with seven resolved spectral features. The electron affinity of Al6N has been determined to be 2.58 +/- 0.04 eV. Global minimum structure searches for A6N- and its corresponding neutral form are performed using several theoretical methods. Vertical electron detachment energies, calculated using three different methods for the lowest energy structure and a low-lying isomer, are compared with the experimental data. The ground-state structure of Al6N- is established from the joint experimental and theoretical study to consist of an Al2 dimer bonded to the top of a quasi-planar tetracoordinated N unit, Al4N-, or it can be viewed as a distorted trigonal prism structure with the N atom bonded in one of the prism faces. For neutral Al6N, three low-lying isomers are found to compete for the global minimum, two of which are built from the tetracoordinated Al4N unit. The chemical bonding in Al6N- is discussed on the basis of molecular orbital and natural bond analyses.
利用光电子能谱和从头算计算研究了氮掺杂铝簇（Al6N-）的电子结构和几何结构。在三种光子能量下获得了Al6N-的光电子能谱，具有七个分辨的光谱特征。已确定Al6N的电子亲和能为2.58±0.04 eV。使用几种理论方法对A6N-及其相应的中性形式进行了全局最小结构搜索。使用三种不同方法对最低能量结构和一个低能异构体计算的垂直电子脱离能与实验数据进行了比较。通过联合实验和理论研究确定Al6N-的基态结构由一个Al2二聚体键合到一个准平面四配位N单元Al4N-的顶部组成，或者可以看作是一个扭曲的三棱柱结构，其中N原子键合在棱柱的一个面上。对于中性Al6N，发现有三种低能异构体竞争全局最小值，其中两种由四配位Al4N单元构成。基于分子轨道和自然键分析讨论了Al6N-中的化学键。
