The water molecules trapped by the excess electron

水分子被多余的电子捕获

基本信息

批准号：
11640518
负责人：
IWATA Suehiro
金额：
$ 1.86万
依托单位：
Hiroshima University (2000)Okazaki National Research Institutes (1999)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

The water cluster anions and the complexes of a group 1 metal atom with water clusters are studied with the ab initio MO calculations. They commonly have a structural unit of the excess electron cloud surrounded by a few HO bonds. The unit is called the OH {e} HO structure. The HO bonds interacting with the electron cloud {e} have harmonic frequencies shifted to downward and their bond lengths are lengthened, similar to the HO bond in the hydrogen bond. Thus, the bond {e} HO can be called electron-hydrogen bond.The photoionization spectra of water cluster anions are studied with L2 integral basis set. The isomerand size-dependence of the spectra are examined. The photoabsorption spectra of the complexes of a group 1 metal atom with water clusters are also studied, and the dramatic size dependence is demonstrated. A series of Rydberg type transitions are found for the clusters.It has been known that the Basis Set Superposition Error (BSSE) has serious effects in evaluating the binding energy of weak molecular and atomic complexes. The method to remove the BSSE has been a long research subject in quantum chemistry. We have developed the locally projected scf MO (LP SCFMO) for molecular interaction, which can be applicable to clusters having any number of molecular units. The new method is presented with projection operators, and the formula are transparent and their meanings are clear. The LP SCFMO was applied to water clusters, and the size dependence and basis set dependence were systematically examined. The results demonstrate that the SCF level of approximation of LP MO theory substantially underestimates the binding energy. It is because the LP SCF does not contain the electron delocalization over the molecular units. To improve the method, the perturbation expansion is required with the non-orthogonal molecular orbitals. The computational procedure is under development.

通过从头计算 MO 计算，研究了水簇阴离子以及第 1 族金属原子与水簇的络合物。它们通常具有被一些 H2O 键包围的过量电子云的结构单元。该单元称为 OH {e} HO 结构。与电子云{e}相互作用的HO键的谐波频率向下移动并且它们的键长延长，类似于氢键中的HO键。因此，键{e} H2O可称为电子-氢键。利用L2积分基组研究了水簇阴离子的光电离谱。检查光谱的异构体尺寸依赖性。还研究了第 1 族金属原子与水簇的络合物的光吸收光谱，并证明了显着的尺寸依赖性。团簇中发现了一系列Rydberg型跃迁。众所周知，基集叠加误差(BSSE)对评估弱分子和原子配合物的结合能有严重影响。消除BSSE的方法一直是量子化学领域长期研究的课题。我们开发了用于分子相互作用的局部投影scf MO (LP SCFMO)，它可适用于具有任意数量分子单元的簇。新方法提出了投影算子，公式透明，含义明确。将LP SCFMO应用于水团簇，并系统地检验了尺寸依赖性和基组依赖性。结果表明，LP MO 理论的 SCF 近似水平大大低估了结合能。这是因为 LP SCF 不包含分子单元上的电子离域。为了改进该方法，需要对非正交分子轨道进行微扰展开。计算程序正在开发中。