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X-ray Atomic Orbital and Molecular Orbital Analyzes

X 射线原子轨道和分子轨道分析

基本信息

批准号：
05453021
负责人：
TANAKA Kiyoaki
金额：
$ 4.29万
依托单位：
Nagoya Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05453021/
关键词：
X-ray diffraction method Electron density distribution Atomic orbital Molecular orbital f-electron density distribution Multiple diffraction X線原子軌道解析法 X線分子軌道解析法多重反射 X線原子軌道解析 X線分子軌道解析遷移金属錯体 d軌道関数 4f電子ジフォルムヒドラジド CeBb 多重反射(

项目摘要

A least-squares method incorporating orthonormal relationships between orbital functions were formulated. This is equivalent to the idempotency condition for orbitals occupied by integer number, which is less than 2, of electrons. The first aim of the present research is to obtain atomic orbitals (AO) or molecular orbitals (MO) by analyzing electron density distribution (EDD) measured by X-ray diffraction method with this method. The second aim is to measure so accurate structure factors that EDD in crystals composed of heavy atoms such as rare-earth elements can be obtained reliably.The least-squares method was successfully applied aand 3d-orbital functions of Cu^<2+> in a low symmetry field were obtained. Therefore AO can be obtained by the analysis of X-ray structure factors. We call the method as X-ray AO analysis. The similar research for obtaining MO,which is called as X-ray MO analysis, is still being investigated because unexpectedly long computation time is necessary. However … More following three basic problems has been solved and it is feasible to accomplish X-ray MO analysis. First, in a simple organic compounds scattering factors of two-center electrons is larger than their experimental error for many reflections enough for the least-squares analysis. Second, ttemperature factors for two-center electrons are successfully formulated, giving reasonable R-factors. Third basic Gaussian-type functions which is proper for X-ray MO analysis was found, which reduce the inconsistency of electron density near atomic nuclei significantly.As X-ray analysis of EDD develops more accurate measurement is required. Multiple diffraction effect was found to occur so frequently that intensity perturbations due to it easily exceeded 1% of measured structure factors for PtP_2 crystals. Therefore it was avoided during the measurement with a 4 cirde diffractometer. Intensities were also measured in stable temperature region of toold nitrogen gas stream of the Oxford cryostat. These improvementts were achieved in the present research. As s result of it 4f-electron density distribution in CeB_6 was measured clearly at 165K and it was analyzed based on the crystal field theory by X-ray AO analysis. This to our knowledge is the first successful quantitative analysis of felectrons. The studies on EDD in crystals composed of heavy atoms showed a remarkable progress. Less

建立了包含轨道函数间正交化关系的最小二乘法。这相当于轨道被小于2的整数个电子占据的幂等条件。本研究的第一个目的是通过分析X射线衍射法测量的电子密度分布(EDD)来获得原子轨道(AO)或分子轨道(MO)。第二个目标是测量高精度的结构因子，以便可靠地获得稀土等重原子组成的晶体中的EDD。将最小二乘法成功地应用于低对称场中，得到了Cu^&lt；2+&gt；的三维轨道函数。因此，通过对X射线结构因子的分析，可以得到A0。我们称这种方法为X-射线声光分析。类似的获得分子轨道的研究，被称为X射线分子轨道分析，因为需要意外的长时间计算，所以仍在研究中。然而，…解决了以下三个基本问题，实现X射线分子轨道分析是可行的。首先，在一个简单的有机化合物中，对于足够多的反射，双中心电子的散射因子大于它们的实验误差，足以进行最小二乘分析。其次，成功地推导了双中心电子的温度因子，给出了合理的R因子。第三，找到了适合于X射线分子轨道分析的基本高斯型函数，它显著降低了原子核附近电子密度的不一致性。随着X射线分析的发展，对能谱分析提出了更高的要求。PTP_2晶体的多重衍射效应非常频繁，其引起的强度微扰很容易超过测量结构因子的1%。因此，在用四圈衍射仪进行测量时，避免了这种现象。还测量了牛津低温恒温器中氮气气流的稳温区的强度。这些改进都是在本研究中实现的。由于S的实验结果，我们在165K下清晰地测量到了CeB6中的4f电子密度分布，并根据晶场理论对其进行了X射线AO分析。据我们所知，这是第一次成功地对电子进行定量分析。重原子晶体中的EDD研究取得了显著的进展。较少