CH_2(~3B_1)与NO的基元化学反应研究

Cth和NO都具有未配对电子,它们之间的反应属于自由基之间的反应．该反应可能经历的通道很多,因此研究这个反应,具有重要的学术价值．另一方面,烃类在燃烧过程中可热解成CH、CW、C：H或CIn等自由基碎片’‘’,亚甲基CW与NO的反应是重要的基元反应之一．除此之外NO是重要的环境污染物,在大气中低浓度NO能够存在较长时间”’,可继续与CHZ自由基发生反应．因此就环境保护方面来说,CIn自由基与NO反应的研究也有较大的现实意义．虽然以前很多人都通过实验测出过CW与NO总反应的速车常数’‘,’－’‘,但关于反应动力学方面的…     

四原子分子中Majorana算子矩阵元的新计算公式

李代数方法在研究双原子分子、三原子分子振－转光谱及相关问题等方面已被证明是一种有效方法[‘－0,并被成功推广到多原子分子[’－门．构造代数哈密顿量是此方法的关键,这就要求选择合适的     

二氧化钛超薄膜的组装

近年来LB膜技术和超微粒子研究的发展，将两者有效地结合起来组装了与量子电子学、非线性光学、光电化学、化学生物传感器有关的纳米量级无机半导体材料［‘－‘j．其中TIO。纳米薄膜材料已在太阳能电池反射膜、压电铁电薄膜、电致显示器件［‘j、可逆光电池和超导薄膜［’］研究中都显示了广阔的应用前景．这类薄膜制备多采用化学气相沉积（CVD）技术和原子层外延．也有人把LB技术应用于纳米粒子的组装来制备TIO。超薄膜［”’j二本文利用烷氧基钛在水／空气界面上发生的溶胶一凝胶化反应制备TIO。基胶态粒子及其固态凝聚膜，将其与…     

不同方法制备的Cu-Cr/γ-Al2O3的结构及其对糠醛加氢制2-甲基呋喃反应的催化性能

 利用普通浸渍法、共沉淀法和溶剂化金属原子浸渍法制备了一系列Cu－Cr／γ－Al2O3催化剂，并用X射线衍射、扫描电镜、透射电镜和X射线光电子能谱等技术对这些催化剂进行了表征．结果表明，不同方法制备的催化剂的金属粒度的顺序为溶剂化金属原子浸渍法＜共沉淀法＜普通浸渍法；金属还原程度的顺序为溶剂化金属原子浸渍法＞普通浸渍法≈共沉淀法．糠醛加氢反应实验结果表明，催化活性顺序为溶剂化金属原子浸渍法＞普通浸渍法＞共沉淀法；生成2－甲基呋喃选择性顺序为共沉淀法＞普通浸渍法＞溶剂化金属原子浸渍法．     

H_3PO→H_2POH异构化反应的LMO研究

1引言最近二、三十年来，定域化分子轨道（LM阿理论在化学的各领域内都得到了广泛的应用［‘－‘］．本文试图采用LMO方法的计算来研究化学反应．期望对反应过程中电子在各原子间的转移和重新排布，以及键的断裂和生成有一个具体的了解．对于HaPO、H。POH异构化反应（见图1）来说，可看成是H’原子绕P原子向0原子方向移动的结果，而角度zH‘PO的大小可看成是反应过程的一个标度或“反应坐标”．本文中氢原子的编号H‘护p‘仅是为计算和分析的方便而加以标识的．每给定一个ZH‘PO角度，我｛rl都采用GAUSSIAN80程序在3－21G基组…     

单元练习三参考答案及解题思路分析

单元练习三参考答案及解题思路分析一、二、三、选择进四、项空口２７．（）ＮａＭＭｇＭＡＩＭＬｉ＜Ｄｅ「：Ｆ：」－）,离子键、极性键、配位键’．（３）Ｋ＞Ｃａ＞Ｓ＞ＣＩ（４）Ｏ,Ｎａ,Ｓｔ（５）「：二：］ｉ３Ｍｇ‘”「：ｔｉＢ：：］－＠＠回＠２８．（）２...     

氧阴离子引发甲基丙烯酸-2-(N,N-二甲氨基)乙酯聚合制备Y型大分子单体

氧阴离子聚合(Oxyanion－initiated Polymerization)是一类新型的聚合方法[‘,’‘．利用个乙烯基苦醇钾作为功能性引发剂,引发甲基丙烯酸－2－(NJ－二乙氨基)乙酯聚合,形成末端带可聚合官能团的大分子单体‘”“．氧阴离子引发剂通常难以引发甲基丙烯酸烷基酯单体聚合,但却能引发甲基丙烯酸氨基酯类单体发生聚合．由于氨基乙酯基7位上氮原子的供电子性,它能与钾离子形成螫合物,使氧阴离子的亲核性增加,从而更具有活性,引发单体聚合．氧阴离子聚合具有速度快、活性高、反应温度接近室温和产物的单分散性好等特点．尽管目前还不清楚这种反…     

全氟聚醚润滑油添加剂抗氧抗腐蚀机理研究及分子设计──I.添加剂的作用机理和授受电子性质

采用量子化学方法，全优化计算了含Ｎ的全氟聚醚芳烃和Ｎ－取代全氟聚醚芳 酰胺抗氧抗腐添加剂与全氟聚醚氧自由基（ＲfＯ．）的结合能和与铁原子的吸附作用能． 探讨了这些化合物的结构特征、作用机理、授受电子的性质和取代基效应．计算发现这 些添加剂的ＨＯＭＯ均为带有杂原子孤对电子的π- 分子轨道；添加剂的ＨＯＭＯ可与金属 原子的ＬＵＭＯ发生相互作用，ＨＯＭＯ的电子转移到金属原子的ＬＵＭＯ上形成配位键和 稳定的吸附态．添加剂的ＬＵＭＯ又可与Ｒ-fＯ．的ＳＯＭＯ相互作用，ＬＵＭＯ接受Ｒ－fＯ．的 电子生成稳定的加成产物，添加剂具有授受电子的性质．研究还发现在全氟聚醚芳酰 胺Ｎ原子上引入供电子基团或苯基后，可增加添加剂与ＲｆＯ．的结合能或与铁原子的化 学吸附作用能，预示将增加抗氧抗腐性能．依据计算的结果推测前５个化合物的抗氧抗 腐蚀效果有如下之序：化合物Ⅲ＞Ⅱ＞Ⅰ＞Ⅳ＞Ⅴ．     

肉桂中醛、酸类化合物结构与抗菌活性的关系

本文对肉桂醛、酸及其衍生物的抑菌效果进行了测定，对其量子化学参数进行了计算，并对这类化合物抗菌活性和分子化学结构之间的关系进行了相关分析。结果表明，该类化合物抑菌率EFPO、ELUMO和EHOMO的相关系数分别为一0．7814（p＜0．05）、－0．7328（0．05＜ρ＜0．1）和0．6318（ρ＞0．1）。该类化合物的抗菌活性中心原子可能是羰基氧、α-碳、β-碳，由这些原子组成的不饱和羰基共轭体系可能是抗菌剂的活性功能域．     

1,3,5-三芳基-2-吡唑啉化合物光物理行为的研究

近年来，在分子内电荷转移化合物发光行为的研究中，对分子激发态非辐射衰变通道问题的研究有了较大的进展［‘－’］．在分子结构和所处环境两因素对激发分子非辐射衰变过程影响的研究中，在结构方面已经认识到如化合物分子内双键的特性、杂原子的存在以及分子的几何构象等都可能对化合物的发光行为带来很大影响［’－’1．特别是分子立体几何构象问题，自F6rster－Hoffmarm提出他们的模型以来同，最近迅速发展起来的所谓“扭曲的分子内电荷转移（TICT）”概念同，使分子构象问题在荧光、激光染料的光物理研究中占有十分重要的位置．按…     

Stimulated emission at the sum-frequency generation of a bichromatic field interacting with a three-level atom

The Maximum-Entropy formalism is used to obtain approximations to the spherically averaged charge and momentum densities. The only information required is the first few radial expectation values. Analytical and numerical approximations to the central values of the densities are calculated. Moreover, the unused or unknown radial expectation values are estimated by means of the moments of these Maximum-Entropy densities. As illustration, the accuracy of these approximations are numerically studied in a Hartree-Fock framework. This method is complementary to the one which makes use of the Stieltjes-Chebyshev inequalities and leads to the least biased approximate densities compatible with the information we use.     

Applications of some bounds to density functionals for atoms

In this article, some applications of lower bounds to density-dependent functionals in terms of radial expectation values are performed. These diverse applications include accurate upper bounds to the exact kinetic energy and to conjecture a wide set of relationships among radial and momentum expectation values. Some open questions for the improvement of these results are remarked upon. © 1995 John Wiley & Sons, Inc.     

New bounds for the atomic charge and momentum densities at the origin

The “Stieltjes moment problem” technique together with the positivity and monotonic decreasing properties of the electronic density of an atom is used to find new and more accurate lower bounds for the charge density at the nucleus and the momentum density at the origin, in terms of radial and momentum expectation values, respectively. Bounds depending on two and three expectation values are given explicitly and a Hartree-Fock study of their quality is carried out. Also, the behavior of the new bounds at largeZ's is discussed. The Stieltjes technique allows to find lower bounds of better accuracy by including expectation values of higher order.     

Revisiting the generalized pseudospectral method: Radial expectation values,fine structure,and hyperfine splitting of confined atom

This paper revisits the generalized pseudospectral (GPS) method on the calculation of various radial expectation values of atomic systems, especially on the spatially confined hydrogen atom and harmonic oscillator. As one of the collocation methods based on global functions, the powerfulness and robustness of the GPS method has been well established in solving the radial Schrödinger equation with high accuracy. However, in our recent work, it was found that the previous calculations based on the GPS method for the radial expectation values of confined systems show significant discrepancies with other theoretical methods. In this work we have tackled such a problem by tracing its source to the GPS method and found that the method itself may not be able to obtain the system wave function at the origin. Combined with an extrapolation method developed here, the GPS method can fully reproduce the radial quantities obtained by other theoretical methods, but with more flexibility, efficiency, and accuracy. We apply the GPS-extrapolation method to investigate the relatievistic fine structure and hyperfine splitting of confined hydrogen atom in s-wave states where the zero-point wave function dominates. Good agreement with previous predictions is obtained for confined hydrogen in low-lying states, and benchmark results are obtained for high-lying excited states. The perturbation treatment of the fine and hyperfine interactions is validated in the confining environment.     

Standard deviation in reduced errors (SDRE): A criterion to assess the relative overall quality of approximate wavefunctions

The standard deviation in reduced errors (SDRE) quantitatively measures the similarity between an approximate and exact wavefunction. It is the Euclidean distance between the vector of the one-electron property expectation values calculated using the approximate and exact expectation values.     

Discrete variable approaches to tetratomic molecules: part I: DVR(6) and DVR(3) + DGB methods

We present two discrete variable representation (DVR) based methods for the determination of the vibrational energy levels of tetratomic molecules. Both methods are designed for orthogonal internal coordinates in a body-fixed reference frame and make use of the DVR of three angular variables. The angular DVRs allow the construction of a fixed-angle three-mode Hamiltonian for the stretching vibrations. For each of the angular triples, the stretching eigenvalue problems are solved by employing 3D radial DVRs in the DVR(6) approach and real three-dimensional distributed Gaussian functions in the DVR(3) + DGB method. The angular degrees of freedom are taken sequentially into account in conjunction with a contraction scheme resulting from several diagonalization/truncation steps. Vibrationally averaged geometries, expectation values of rotational constants, and several adiabatic projection schemes developed in this work for tetratomic molecules are used to characterize the vibrational levels calculated by the DVR(6) and DVR(3) + DGB.     

非自由态Cu(Ⅱ)的径向波函数及其电子结构

本文利用非自由态离子的标度径向理论给出了非自由态Cu(Ⅱ)的3d径向波函数,讨论了Jahn-Teller效应对非自由度的影响。计算了一些Cu(Ⅱ)络合物的d-d电子光谱和g-因子,计算结果与实验值较为一致。     

Molecular properties from coupled-cluster Brueckner orbitals

We investigate to which extent a single determinant made up from orbitals obtained by a Brueckner coupled-cluster doubles calculation is able to reproduce correlated one-electron properties. It is shown that dipole and quadrupole moments and radial expectation values compare quite well with BCCD finite-field results for a test selection of nine molecules enclosing HF, H₂O, NH₃, CO, N₂, NO⁺, HCN, CuH and CH₃OH and three rare-gas atoms He, Ne and Ar. Furthermore, we find that even second-order properties such as dipole and quadrupole polarizabilities are reproduced fairly well when determined as first derivatives of the corresponding Brueckner orbital expectation values.     

Iterative hypervirial-scaling method for obtaining wave functions and eigenvalues

A procedure to improve trial wave functions is given in terms of the off-diagonal hypervirial theorem. This procedure is closely related to the optimum scaling method which is valid for the diagonal hypervirial theorem. The second excited state of the one-dimensional oscillator model is employed as an example, and improved wave functions and expectation values are calculated. The results are compared with previous values based on the diagonal hypervirial theorem.     

非自由态Mn(Ⅱ)的径向波函数及其电子结构

应用非自由态离子标度径向理论,以“非自由度”作为衡量非自由态的指标,从实验值求出过渡系数,得到了非自由Mn(Ⅱ)的径向波函数。利用该函数计算了一些Mn(Ⅱ)络合物的d-d电子光谱,计算结果与实验值较为一致。