Electronic Structure of Semiconductor and Main Group Cluster

美国亚利桑那州立大学化学与生物化学系的Krishnan Balasubramanian教授获得了美国国家科学基金会理论与计算化学项目的资助，从事分子和小簇电子结构的理论研究。精确的从头算波函数已经在几个系统中得到，这些系统都包含半导体或其他主要族元素。被研究的体系分为三组：(1)混合III-V， IV-V和II-VI团簇，最多有9个原子。(2)由III族、IV族和V族元素组成的最多8个原子的纯团簇。(3) III族和V族元素的氢化物和卤化物。在这个工作中，相对论效应被明确地处理，因为当所研究的系统包含重原子时，为了能够获得精确的能量和几何性质，它们是必需的。在这项工作中处理的重原子的例子有镓、铟、铅和硒。为了使波函数的计算易于处理，特别是对于较大的簇，使用相对论有效核势来表示原子核中的电子。为了获得所需的精度，利用多参考位态相互作用和相对论位态相互作用方法，进一步将相对论性完全主动空间自洽场波函数进行关联。这项资助下的工作旨在解决有关半导体和含有重原子的主要团簇的广泛性质的问题。团簇是分子和固体之间的重要桥梁。然而，它们本身也表现出有趣和技术上有用的特性。在这个项目中，所研究的系统与半导体加工和化学气相沉积有关。

Professor Krishnan Balasubramanian at the Department of Chemistry and Biochemistry, Arizona State University, is supported by a grant from the Theoretical and Computational Chemistry Program at NSF for theoretical studies of the electronic structure of molecules and small clusters. Accurate ab initio wavefunctions are being obtained for several systems, all of which contain semi-conductor or other main group elements. The systems being studied fall into three groups: (1) Mixed III-V, IV-V, and II-VI clusters with up to 9 atoms. (2) Pure clusters with up to 8 atoms formed from group III, IV, and V elements. And, (3) hydrides and halides of group III and V elements. In this work relativistic effects are explicitly treated because they are needed in order to be able to obtain accurate energetic and geometric properties when the systems studied contain heavy atoms. Examples of heavy atoms treated in this work are gallium, indium, lead, and selenium. Relativistic effective core potentials are used to represent the electrons in the atomic cores in order to make calculations of the wavefunctions tractable, especially for the larger clusters. In order to obtain the required accuracy, relativistic complete active space self-consistent field wavefunctions are further correlated using multi-reference configuration interaction and relativistic configuration interaction methods. The work under this grant is directed toward resolving questions about a wide range of properties of semi-conductor and main group clusters containing heavy atoms. Clusters constitute a vital bridge between molecules and solids. However, they also exhibit interesting and technologically useful properties in their own right. In this project, the systems studied have relevance for semi-conductor processing and for chemical vapor deposition.