DEVELOPMENT OF COMPUTATIONAL PROGRAM FOR MOLECULAR ORBITAL CALCULATIONS WITH MODEL CORE POTENTIAL METHOD

对于含有重原子的分子，所有的电子从头计算有时是不可能的。Sakai和同事开发了一种Li到Rn原子的模型核心电位（MCP）方法。MCP方法是一种有效的核心电位（ECP）方法，但它的独特之处在于它能够产生具有节点结构的价轨道。对于比Kr重的原子，主要的相对论效应（质量速度项和达尔文项）在Cowan和gffin的准相对论hartri - fock （QRHF）方法的水平上被纳入MCPs。能量梯度法可用于确定势能表面上的能量最小值、过渡结构、振动分析和反应途径。能量梯度法在MCP方法中的应用，为化学反应和催化机理的理论研究开辟了新的可能性。通过助学金，我们完成了将MCP及其能量梯度方法安装到计算程序“GAMESS”中的工作。实际上，我们用这个程序来研究含有镧系和锕系原子的分子的几何形状和电子结构；(1) GdO的激发态；(2)铀和钕卤素化合物。现在我们继续将MCP程序安装到“高斯”。

All electron ab initio calculations are, some time, impossible for molecules containing heavy atoms. Sakai and coworkers have developed a model core potential (MCP) method for the atoms Li through Rn. The MCP method is an effective core potential (ECP) method, yet it is unique in that it is capable of producing valence orbitals with nodal structures. For atoms heavier than Kr, the major relativistic effects (the mass-velocity and Darwin terms) were incorporated in the MCPs at the level of Cowan and Gfiffin's quasi-relativistic Hartree-Fock (QRHF) method. The energy gradient method is available to determine the energy minimum, transition structures, vibrational analysis, and reaction pathway on the potential energy surfaces. Application of the energy gradient method to the MCP method opens the additional possibility for the theoretical study of chemical reactions and catalytic mechanism.By the Grant-in-Aid, we finished to install the MCP and its energy gradient method into the computational programs, "GAMESS". We apply this program to study the geometries and the electronic structures of the molecules containing lanthanide- and actinide-series atoms, actually; (1) the excited states of GdO, and (2) Uranium and Neodymium halogens compounds. We now continue to install our MCP program to "GAUSSIAN".