A New Relation Connecting Vibrationai Constant and Electronegativity in the Case of Diatomic Molecules

The electronegativity was defined by Pauling¹ as a measure of the power of an atom in the molecule to attract electrons to itself. This concept of electronegativity has undergone radical changes. Recent calculations of electronegativity show^2,3 that it is a complex quantity including an important atomic term depending on the charge and hybridization of the atom, and a molecular term depending on the length and the nature of the bonds in the molecule. In a molecular group of the type A-B, B is a halogen atom, say chlorine and A stands for different atoms of a subgroup of the periodic table. Since the nature of the bonds in the molecule AB and the electronegativity of halogen atom, B, is constant for a molecular group, the electronegativity, X, of atom A may be related to the dissociation energy and bond length which in its turn is related to the vibrational constant,ω_e, and the reduced mass, μ, of the molecule AB.     

A New Type of High Frequency Vibrational Modes for Diatomic Chain with Quartic Substrate Nonlinearity

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Circularly Polarized Luminescence of Free Complex Molecules in a Constant Magnetic Field

It is shown that the magnetic fieldinduced optical activity in the luminescence of complex molecules in vapors in the presence of rotational anisotropy in the ensemble of luminescent molecules provides information also on the intramolecular orientation of the initiating dipole moments of transitions, including borrowed ones. The relationships between the rotational force of the optical activity and this orientation in the case of anisotropy induced by a linearly polarized exciting light are obtained.     

一种由酸效应系数计算pH值的简便方法

利用数学不等式关系推导出一种新的由酸效应系数计算pH时非线性部分的修正方法。本法无需进行指数和对数运算,方法简便,计算结果令人满意。     

A Vibrational Force Field For 1-Alkynes and Nitriles

Abstract

Normal coordinate calculations were made for 1-butyne, propionitrile, and the two conformers each of 1-pentyne and butyronitrile, using a thirty-one parameter modified valence force field. Only the triple bond stretching force constant was assumed to be different in the two families of compounds. Twenty force constants were refined to fit 117 frequencies of the six molecules, with the average error being 5.1 cm^?1, or 0.65%.     

Multiple-Photon Dynamics in Molecules: A New Approach to High Resolution Spectroscopy of Highly Excited Vibrational States

Multi-photon transitions with two simultaneously interacting IR laser fields lead to final excited states with frequenciesnν = n₁ν₁+ n₂ν₂, withnthe total number of photons absorbed and (n,n₁,n₂) = (2, 1, 1), (3, 2, 1), (4, 1, 3), etc. The nature of the actual transition is determined by shift measurements, where the lasers are frequency-tuned by δν_iin opposite directions keeping the sum frequency,nν, resonant with the molecular transition. This technique opens a new spectral range for multi-photon transitions and a unique identification of the observed features. Forn₁andn₂both positive the excitation will lead to a “normal” up–up multi-photon transition. Many three- and four-photon transitions in the ν₃vibrational ladder of SF₆could be resolved with a resolution of 1 MHz, as well as four new two-photon transitions. As long asn₁+ n₂≥ 0, one of the twon_imay be negative resulting in an, e.g., up–down excitation pathway with its particular selection rules. The up–down excitations are demonstrated both for one- and two-photon transitions using the frequency shift technique. The different possible excitation schemes which meet the resonance condition for these transitions lead to interference effects and local couplings to highly excited states. Changes in resonance frequency for a one-photon transition (n= 1), due to these effects, are demonstrated. Evidently, the radiative coupling of participating levels to high-lying or quasi-continuum states may drastically change for different δν_ileading both to ac Stark shift and transition probability variations.     

A General Variational Algorithm to Calculate Vibrational Energy Levels of Tetraatomic Molecules

A general variational method for calculating vibrational energy levels of tetraatomic molecules is presented. The quantum mechanical Hamiltonian of the system is expressed in a set of coordinates defined by three orthogonalized vectors in the body-fixed frame without any dynamical approximation. The eigenvalue problem is solved by a Lanczos iterative diagonalization algorithm, which requires the evaluation of the action of the Hamiltonian operator on a vector. The Lanczos recursion is carried out in a mixed grid/basis set, i.e., a direct product discrete variable representation (DVR) for the radial coordinates and a nondirect product finite basis representation (FBR) for the angular coordinates. The action of the potential energy operator on a vector is accomplished via a pseudo-spectral transform method. Six types of orthogonal coordinates are implemented in this algorithm, which is capable of describing most four-atom systems with small and/or large amplitude vibrational motions. Its application to the molecules H₂CO, NH₃, and HOOH and the van der Waals cluster He₂Cl₂ is discussed.     

A New Invariant For G-Invariant Star Products

The purpose of this Letter is to propose an invariant for a G-invariant star product on a G-transitive symplectic manifold which remains invariant under the G-equivalence maps. This invariant is defined by using a quantum moment map which is a quantum analogue of the moment map on a Hamiltonian G-space. On S ² regarded as an SO(3) coadjoint orbit in , we give an example of this invariant for the canonical G-invariant star product. In this example, there arises a nonclassical term which depends only on a class of G-invariant star products.     

A New Model For the Double Well Potential

A new model for the double well potential is presented. In the new potential, the exchanging rate could be easily calculated by the perturbation method in supersymmetric quantum mechanics. It gives good results whether the barrier is high or sallow. The new model has many merits and may be used in the double well problem.     

Cooper对质心定向运动速度的研究

研究了稳恒超导电流密度 j=ensνs中 ,νS在产生磁场方面的作用 ;指出超导抗磁性起源的物理本质是 ,νSC(T)很大 (约为 1 0 3 - 1 0 4 ms- 1) ,νSC(0 )的上限是 0 K时电子 Fermi速度 (数量级为1 0 5ms- 1) ;并说明了 London穿透深度的物理意义。指出 L ondon穿透深度是产生拆对磁场 Hc(T)所要求的 Jc(T)分布的最小线度。     

A New Proof of the Analyticity of the Electronic Density of Molecules

We give a new proof of the regularity away from the nuclei of the electronic density of a molecule obtained by Fournais et al. (Commun. Math. Phys. 228(3):401–415, 2002; Ark. Math. 42(1):87–106, 2004). The new argument is based on the regularity properties of the Coulomb interactions underlined by Hunziker (Ann. Inst. Henri Poincaré, section A, tome 45, no. 4, pp 339–358, 1986) and by Klein et al. (Commun. Math. Phys. 143(3):607–639, 1992). Well-known pseudodifferential techniques for elliptic operators are used and the method works in a larger framework.     

提高多孔硅传感特性的一种新方法(英文)

研究了多孔硅(PS)吸附有机溶剂分子后对多孔硅荧光谱的淬灭效应。结果表明:淬灭多孔硅发光的有机溶剂分子是极性分子,有机溶剂分子的极性不同对多孔硅发光的淬灭程度也不同,且有些有机溶剂分子吸附氧化多孔硅比吸附多孔硅引起的发光淬灭具有更好的可逆性和选择性;用含有胺基的正丁胺(CH3CH2CH2CH2-NH2)作碳源,用射频辉光放电等离子系统在多孔硅表面沉积c n膜对多孔硅进行钝化处理后发现:其电致发光强度明显增强,发光峰位兰移,且在大气中存放60天后,其电致发光谱强度基本不衰减,峰位不再移动。经钝化处理的器件较未经处理的器件具有小的串联电阻Rs和低的驱动电压。这为提高多孔硅的传感特性提供了一种新方法。     

一种新的反向投影条纹生成方法研究

反向条纹投影技术是一种应用于在线或批量检测的快速而稳定的光学三维面形检测技术.提出了一种新的产生反向条纹的算法,新的算法建立投影器坐标系与摄像机坐标系的正向映射变换关系,通过投影器坐标系上一个像素点的两套相位值,找到其在摄像机坐标系中对应的位置,即产生投影器坐标系像素点在摄像机坐标系中的注册.由于期望在摄像机中观察到的条纹图像只是简单的正弦条纹图像,直接读取注册点的期望条纹相位,很容易产生反向条纹.计箅机模拟和反向条纹投影实验中的相位标准差分别达到7.044×10-6 rad和3.34×10-2rad,比以前的方法在精度上有了较大的提高,并简要分析了精度提高的原因.计算机模拟和实物测试实验都验证了该方法的可行性.     

一种基于CCD的实时测量光栅常数的方法

光栅常数是检验光栅质量的重要参数之一.该文介绍了一种实时检测光栅参数的方法,即利用面阵CCD采集光栅衍射图像信息,通过计算衍射±1级光斑与主极大光斑的能量比得出光栅常数.这种方法具有检测速度快、系统简单、精度高等特点,可用于生产线上光栅的实时检测.     

Dynamic Polarizabilities of Diatomic Molecules: A Comparison of the ab initio and Density Functional Theory Methods with the Reduced-Added Green Function Method of the Quantum Defect Theory

Optics and Spectroscopy - The quantum defect theory is used to test the accuracy of the ab initio and density functional theory (DFT) methods in calculations of the dynamic polarizabilities of...     

A New Dielectric Grating Antenna with Large Leakage Constant for Millimeter-Wave Applications

The leakage properties of a new dielectric grating leaky wave antenna are carefully examined by an approach of combining the multimode network theory with the mode-matching method. A systematic comparison is given for the leaky characteristics of the n = −1 space harmonic of TM mode polarization between the present antenna and the traditional one. It has been found that the former is not only of lower conductor loss, but also of larger leakage constant than the latter. As a result, the dimension of the antenna could be largely reduced, which is of practical significance for some applications. Extensive numerical results of the radiation characteristics are given to establish useful guidelines for the design of the new grating antenna. Furthermore, special features such as cancellation or resonance effects are high-lighted and discussed. Physical insights for the mathematical findings are also presented.     

一种大口径大非球面度天文镜面磨制新技术

主动抛光盘技术是近年来因天文望远镜的口径越来越大,焦比越来越快而发展起来的一种能够根据需要将抛光盘面实时地主动变形成偏轴非球面来磨制大口径非球面度高精度天文镜面的磨制技术。非球面表面的曲率不仅各点不一致,而且同一点的径向与切向曲率也不相同,所以经典的大的抛光盘不可能使其表面形状始终与所接触的非球面表面形状相吻合;常用的小磨盘抛光的致命缺点是解决不了高频切带,抛光效率也低。而主动抛光盘技术正好解决这些难题。与传统方法相比,它具有较高的磨削速率和较大范围内的自然平滑(无切带)。这是一种用计算机控制的磨镜技术,通过它可以像加工球面一样来加工一个深度的非球面。介绍了我国成功研制的主动抛光盘以及它在直径910mm,焦比F／2抛物面镜加工中的成功应用和加工的结果,以及此项技术将在2m以上直径天文镜面,特别是30m巨型天文光学／红外望远镜的分块子镜磨制中的应用前景。