价键理论中的组态相互作用

Configuration interaction tenichque is applied to the valence bond theory. Virtual VB orbitals are built, which are localized and orthogonal to their corresponding occupied orbitals and the excited VB structures are defined, which come from their corresponding fundamental VB structures. The testing calculations of H 2, LiH, HF show that the VB results using CI method match those of the molecular orbital based on the coupled cluster CCSD method, and the CI technique may become a useful tool in VB method

S_N2反应X_l~-+CH_3X_r→X_lCH_3+X_l~-(X_l=X_r=F,Cl,Br,I)的价键方法研究

应用最近发展的价键组态相互作用 ( VBCI)方法计算了 SN2反应 X-l +CH3 Xr→ Xl CH3 +X-r ( Xl=Xr=F,Cl,Br,I)的反应能垒和价键相关参数 .计算结果表明 ,VBCI能垒与采用分子轨道理论的 CCSD( T)方法计算的能垒相一致 .讨论了 SN2反应的反应参数

VBDFT(s) - a semi-empirical valence bond method: Application to linear polyenes containing oxygen and nitrogen heteroatoms

A semi-empirical valence bond (VB) method, VBDFT(s), is applied to the series of linear polyenes with heteroatoms CM -1HMO, CM - 2HM - 2O2, CM - 1HM + 1N, and CM - 2HMN2 (M = 4-26). The computational results show that the VBDFT(s) method, which was first applied to linear polyenes, is also suitable for treatment of linear polyenes with polar bonds. Properties such as the wavefunction, extent of delocalization, the resonance energy, and the energy additivity are discussed

现代价键理论研究进展

概述现代价键理论的几个主要方法 ,以及它们的特点和发展现状 .并重点介绍了对不变行列式方法和相应的计算程序

从头算VB-MP2组合方法

提出了一种经济实用的价键计算方法 VB-MP2方法 .将体系的电子分为非活性电子和活性电子 ,应用 MP2方法计算非活性电子的相关能效应 ,用 VB方法处理活性电子 .测试计算表明 ,该方法保持了价键方法的特点 ,且计算结果比传统的使用芯 -价分离技术的价键方法有较大的改善

价键理论的对不变式方法——Ⅱ.无自旋价键计算程序Xiamen

发展完善了价键理论的对不变式方法,给出了对不变式的正则展开方法,并证明了对不变式可以展开成任意阶的子对不变式和相应余子式乘积的形式.利用对不变式方法,完成一个新的无自旋价键理论方法从头计算程序——Xiamen.测试计算表明,Xiamen程序比基于传统价键方法的程序计算效率高,为量子化学计算研究提供了一个新工具

Configuration interaction in valence bond theory

Configuration interaction tenichque is applied to the valence bond theory. Virtual VB orbitals are built, which are localized and orthogonal to their corresponding occupied orbitals and the excited VB structures are defined, which come from their corresponding fundamental VB structures. The testing calculations of H-2, LiH, HF show that the VB results using CI method match those of the molecular orbital based on the coupled cluster CCSD method, and the Cl technique may become a useful tool in VB method

A Study on Valence Bond Theory and Its Applications

在量子化学中，价键理论和分子轨道理论是人们用来描述原子、分子及化学反应的两个并行的方法。价键理论的基本思想是两个有关原子轨道重叠形成化学键，这与传统的化学理论是一致的。然而正是因为引入了非正交的原子轨道导致了计算上的“N!”困难，使得价键理论的发展远远落后于分子轨道理论。近二十年来，由于电子计算机技术的迅速发展，价键理论重新得到了人们的重视。本文试图对价键理论的基本方法及其应用方面进行较为系统的研究，研究工作主要包括三个方面： 1.价键理论的发展 关于矩阵元计算的“N!”困难，本文第二章将我们小组提出的对不变式方法进行了发展和完善。推导出了S=0时对不变式的任意阶展开公式，以及对不变式...Two approaches are used in quantum chemistry to study atoms, molecules, and chemical reactions. One approach is valence bond (VB) theory, and the other approach is the molecular orbital (MO) theory. VB theory is based on the concept that chemical bonds originate from the overlap of atomic orbitals, which coincides with traditional chemistry theory. However, the notorious N! problem resulted from t...学位：理学博士院系专业：化学化工学院化学系_物理化学(含化学物理)学号：B19992502

Program Implementation of a New Algorithm For the Evaluation of the Standard Orthogonal Representation For Symmetric Groups

进一步完善了对称群的标准正交不可约表示矩阵计算新方法，实现了该方法的程序化.该程序可以移植到有关的多电子理论方法计算程序，也可以作为独立的程序用于计算表示矩阵.此外，列出一些简单表示的内禀矩阵.An eFFicient algorithm For evaluating the standard orthogonal representation For sysmmetric groups is Further improved and implemented.The program can be applied eFFectively not only to the evaluatation of the representation matrices, but also to other calculation programs of many electron systems in quantum chemistry.Furthermore, some simple intrinsic matrices of irreducible representation are listed.国家自然科学基

A Valence Bond Study of Electron Transfer Process in Alkane Systems

应用价键理论研究直链烷烃体系的电子转移过程,直接计算得到的耦合能与实验值以及其它的理论计算结果一致.对于阳离子系列,BOVB方法和VBC IS方法都给出了与实验相符的计算结果,但对于阴离子系列,VBC IS方法的β值基本一致,而BOVB方法的β值较大.计算结果表明,价键理论可以应用于电子转移的理论研究,而VBC IS方法是研究电子转移问题的一种合适的价键计算方法.The electron transfer process in trans alkyl chain systems was studied by valence bond theory at BOVB and VBCIS levels.For the cation systems,the results obtained with the two methods are both in good agreements with experimental values.For the anion systems,the results obtained with VBCIS method matches fairly the experimental values,while the β value of BOVB was higher than that of experiment.The results obtained from our study show that the valence bond theory provides a potential tool for studying the electron transfer process.国家自然科学基金(批准号:20373052,20225311,20403013)资