电子动量谱仪的研制和He原子结构的研究

前文指出，电子动量语学是研究原子和分子结构的一种新方法，其价值在于：它既能直接得到电子能级，又能相当直接和精细地得到各个电子态的动圭分布（屯就是动会表象中的电子波函数模方）．这些信息对量子化学等学科是极为有用的．在发达国家，电子动量语学已受到广泛的重视，但在国内还几乎是空白．虽然少数单位正在或准备开展这一工作，然而至今还没有成功的实验报导，其原因是国内还没有电子动量谱仪（Elec－tronM。nt。Spectro。ter，缩写为EMS），它是开展电子动量谱学实验的关键设备，在现阶段的国内外市场上均无产品出售，需要使…     

He原子基态波函数的实验检验

以作者所在实验室最近完成的He原子基态的电子动全港学实验结果为基础，对三类He原子基态波函数进行了分析与检验．结果表明，电子动量话学是获取电子波西数信息的有用手段．且实验结果与理论计算的联系文＊已报导了本实验室最近完成的He原子基态的电子动量话学实验结果．此实验的条件满足准自由碰撞的要求问，平面波冲量近似是适用的，因而实验测定的（e，Ze）反应的符合计数N可表为问本文自始至终采用原子单位（an），除非另有说明．在（1）中，C是比例常数，只与实验条件有关；PO，PI和马分别是人射电子和两个出射电子的动量，Th是…     

Spectrochemical Properties of Noncubical Transition Metal Complexes in Solutions. XV. Solution Properties of bis(Salicylideneaniline)Copper(II)

The complex obtained by condensation of salicylideneaniline with copper(II) acetate was studied in a variety of solvents. This deep-brown crystalline compound is soluble in common solvents, such as, chloroform, toluene, dioxane, methanol, ethanol, dimethyl formamide, dimethyl sulfoxide, and acetonitrile—a necessary condition for observing solvatochromism. The complex has been characterized by elemental analysis, molar conductivity, EPR, and ultraviolet (UV) and visible (VIS) spectroscopy. The available X-ray data shows planar coordination geometry for the copper center. Combined multi-technique experiments have been applied to confirm the structure of the complex in solution. The molar conductivities indicate nonelectrolytic properties. EPR measurements preclude the possibility of solvent coordination at the axial positions of the complex. Spectroscopic measurements were used to study the coordination properties of donor atoms and their bonding ability, as well as trichromaticity coordinate calculations. The results obtained show that the interactions of metal with donors depend on donor strength and polarity of solvent.     

Study of molecular orbitals in momentum space

Molecular orbitals are presented in configuration and momentum representations. We propose to minimize large oscillations present in calculated momentum wavefunctions by cancelling position factor phases. We illustrate the distortion introduced by different electron translation factors and show continuum states and dynamical wavefunctions in momentum coordinates. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

Influence of electronic correlation in monoelectronic density in p-space

The radial molecular monoelectronic density and their orbital contributions have been calculated in the momentum space. For these purposes, densities for the ground state of several atoms and molecules, using a cc-pVTZ basis set at HF level, as well as some post-HF and DFT methods are computed. The difference between the radial monoelectronic density computed with each method and that using the HF wave function is used as a tool to study the influence of the electronic correlation in the momentum space. Densities obtained with post HF calculations show a similar behavior around p = 1.0 and 2.0, that are different from the DFT results. Radial momentum densities (p-densities) are more influenced by the electronic correlation than the exchange part of the DFT methods. CISD p-density is more affected than DFT p-density when the intermolecular distance increases. An analysis of the powers of moments calculated with different methods has been carried out. Contribution to the Serafin Fraga Memorial Issue.     

Measuring the electronic structure of disordered overlayers by electron momentum spectroscopy: the Cu/Si interface

The Cu? Si interface was studied by electron momentum spectroscopy. A thick disordered interface is formed if one material is deposited on the other. Electron momentum spectroscopy measures intensity as a function of binding energy and target electron momentum. Momentum resolution is demonstrated to be very helpful in interpreting the data, even for these disordered interfaces. The interface layer has a well‐defined electronic structure, different from either Si or Cu, and consistent with silicide formation. Information is obtained about the total bandwidth of the interface compound, effective Brillouin zone size and Fermi radius. No clear differences are observed in the electronic structure of the interface layer for Si deposited on Cu or Cu deposited on Si. Copyright © 2006 John Wiley & Sons, Ltd.     

Unified treatment of complete orthonormal sets of functions in coordinate,momentum and four-dimensional spaces and their expansion and one-range addition theorems

The simpler formulas are derived for the complete orthonormal sets of exponential- type orbitals, momentum space orbitals and hyperspherical harmonics and their expansion and one-range addition theorems. The continuum states are not properly included in these functions. The analytical formulas are also obtained for the overlap integrals over Ψ^α-ETOs, their extensions to momentum and four-dimensional spaces and STOs with the same screening constants using addition and expansion theorems derived in this paper. The complete orthonormal sets of functions and their expansion and one-range addition theorems obtained can be useful in the study of different quantum mechanical problems when the coordinate, momentum or four-dimensional spaces employed.     

A time-resolved quadrupole mass spectrometric study on 355 nm laser ablated species ejected from LiMn2O4

Mass, velocity and angle distributions of the ablated species generated from 355 nm pulsed laser ablation of a LiMn2O4 target were investigated with an angle- and time-resolved mass spectrometric technique. Both neutral and ionic species of Li, O, LiO, LiO2, Mn, Li2, Li4, Li6, LiMn, MnO and MnO2 were observed at the laser fluence of 0.8 J · cm-2. The yield and variety of the ablated species increase with increasing the laser fluence. The time-of-flight spectra of ablated species can be fitted by a Maxwell-Boltzmann distribution with a center-of-mass velocity. There exist laser fluence thresholds for the ablated LiMn, Li2O and LiO2 species, and the fluence threshold of ionic species is higher than that of neutral species. The angular distributions of the ionic and neutral ablated species can be simulated by a cosnθor a bicosine function αcosθ+(1- α)cos"θ. In addition, the ablation mechanism of LiMn2O4 by a 355 nm pulsed laser is discussed.     

Gauge invariance and renormalization schemes in quantum chromodynamics

A general analysis of the Slavnov-Taylor identity connecting the triple gluon and ghost-ghost-gluon vertices and its consequences for two momentum subtraction (symmetric and asymmetric) renormalization schemes are given. It is shown that in the asymmetric scheme proposed in this paper the relation follows directly from the identity for a simple and natural definition of the renormalization constants. Explicit one-loop expressions for the renormalization constants in an arbitrary covariant gauge, including quark masses are given in support of the general analysis.     

时变系统流场动量定理的积分形式及其在流体动力系数分析中的应用

为解决飞艇的非定常流体动力系数的计算问题,利用准平衡假设在涡量流体动力学理论的基础上构建了一种流体动力系数计算方法.首先提出了时变系统的概念及其与流场空间区域的对应关系,在此基础上建立了时变系统的输运方程和流场动量定理积分形式为后面的讨论做准备.其次,将动量定理应用于一个由无穷远固定边界和物面所包含的流体系统,将流体动力表征为流场扰动动量总和变化率的函数.进而提出准平衡假设的概念,将有粘流中流场扰动速度、第一涡量矩和扰动动量表示为运动体速度和角速度的函数.最后,采用CFD技术,数值确定了这种关系并代入流体动力表达式,得到有粘流中流体动力系数的计算方法.研究结果还表明,由于考虑了系统的时变性,在得到的流体动力表达式中将多出一个稳态流体动力项.这个稳态流体动力项,在无粘流的情况下刚好等于零,与d’Alembert(达朗伯)佯谬的结论一致,在有粘流的情况下不等于零,与实际情况一致.