用代数方法研究H2O和NO2的振动能谱

文内提出一种研究Ｈ２Ｏ和ＮＯ２高激发伸缩振动的Ｕ（２）代数模型,在极限条件下,该模型退化为一种非谐和耦合的局域模模型,用该模型的六个可调参数拟合实验数据,算得的标准偏差比相应的非谐和耦合的局域模型算得的偏差要小。     

XY2型分子伸缩振动与弯曲振动耦合研究

本文研究一种推广的局域模模型，我们用局域坐标描述非线性ＸＹ２分子的伸缩振动，用简正坐标描述弯曲振动；对用曲线内坐标写出的势能函数和Ｇ矩阵元进行Ｔａｙｌｏｒ展开，保留了弯曲振动与伸缩振动耦合的交叉项，获得各阶哈密顿量，略去了五次以上的高阶项；用它对实验数据进行非线性最小二乘法的拟合，得出各个势能参数值，并用它们计算了Ｈ２Ｏ分子的振动光谱，计算结果与实验数据符合得较好。     

非局域非线性克尔介质中两极孤子的变分解

利用变分法对一种假设的两极孤子进行了研究,得到了该两极孤子的参数耦合方程,并对由参数耦合方程得到的结果进行了数值模拟.结果表明,在光束能量较高,趋近于强非局域的情况下,两极孤子横向强度呈一阶厄米-高斯型分布;光束能量较低的弱非局域情况下,两极孤子的两个强度峰之间有一个平台出现.此两极孤子模型还可退化为高斯光束,得到高斯孤子解.     

与纳米腔相耦合的一维波导中的单光子散射

我们研究了与包含三能级原子的纳米腔相耦合的一维耦合谐振器波导中的单光子散射,分别讨论了纳米腔与耦合谐振器波导局域和非局域的两种耦合方式.在局域耦合的情况下,不同偏振光子的透射及反射波谱关于共振点对称.而在非局域情况下,透射和反射系数中的对称性消失,峰和谷的位置向失谐较大处移动.耗散对单光子散射也会产生影响.     

非晶纳米发光材料(Y,Eu)_2O_3-SiO_2发射光谱的分析研究

ＥＸＡＦＳ测定表明ｓｏｌ－ｇｅｌ方法制备的纳米非晶（Ｙ，Ｅｕ）２Ｏ３－ＳｉＯ２发光材料中，发光中心Ｅｕ３＋的局域环境和晶态Ｘ２型Ｙ２ＳｉＯ５Ｅｕ中Ｅｕ３＋离子的局域环境相似．以此结构为依据，用Ｍ．Ｆ．Ｒｅｉｄ的方案计算了晶场迭加模型中的能级参数及光谱强度参数，并得到了与实验结果基本一致的理论光谱图     

光折变全息CO2激光局域热固定

提出用ＣＯ２激光对记录于ＬｉＮｂＯ３晶体中的全息进行实时实时地局域热固定，通过脉冲加热和加载吸热体，可以使得温度范围在１００～２００℃之间的区域接近于加热光的形状，分布于一局部范围，文中给出了加热模型及其数值解，通过得到了最优解参数进行了一系列实验，实验结果显示，用ＣＯ２激光可以成功地光折变全息进行实时地地局域热固定，并且加热时间短，固定转换效率较高。     

双Tavis-Cummings模型中三体纠缠转移及量子极限速度的研究

研究了耦合双Tavis-Cummings模型中三体纠缠态的演化和转移特性。结果表明,初始局域的三体W型纠缠态可以转移为另外局域的三体纠缠,在纠缠转移过程中,两光腔场的耦合参数起到了重要的作用。随着耦合参数的增加,三体纠缠的转移速度加快。并且初始三体纠缠在演化过程中不会完全被局域子体系间所俘获,还会转移到其他非局域子体系上。最后,我们还分析了腔场间耦合强度对初始三体量子态演化速度的影响。     

线性吸收介质非局域线性电光效应的耦合波理论

本文提出了线性吸收介质非局域线性电光效应的耦合波理论,建立了相应的耦合波方程组,并求解了该方程组.由此,可给出在任意方向外加电场的作用下,光在具有空间非局域响应的线性吸收介质中沿任意方向传播时出射光场的表达式.据此,研究了线性吸收是如何改变出射光场的两个偏振分量的振幅、相位和波形的.进一步讨论了线性吸收对电光强度调制的影响,以及如何测量一阶线性和二阶非线性极化率非局域响应的特征长度和介质的线性吸收系数.     

CO2激光局域热固定光折变全息的一种新方法

提出用ＣＯ２激光加热后记录固定的方案对ＬｉＮｂＯ３晶体中的全息进行实时实地局域热固定。通过加载绝热体,利用连续激光加热晶体全部范围至接近２００℃,停止加热开始记录,到该区域温度降屋１００℃时,将固定一个体全息。文中给出了热传导模型及其数值解。由得到的初步结果参数进行了一系列实验。实验结果显示,管种方案可成功地对光折变全息进行实时实时局域热固定,并且具有温度更均匀的特点,所固定的全息质量有较大改善。     

激光上转换玻璃陶瓷材料中稀土杂质Yb^3＋和Tm^3＋局域行为

对红光上转换玻璃陶资ＰｂＦ２＋ＷＯ３＋ＧｅＯ２以及ＰｂＦ２＋ＷＯ３＋ＧｅＦ３＋ＴｍＦ３材料中的微晶相进行了喇曼光谱研究,获得了光谱表明ＰｂＦ２＋ＷＯ３＋ＧｅＯ２＋ＹｂＦ３＋ＴｍＦ３中的微晶是由ＰｂＦ：Ｙｂ＾３＋、Ｔｍ＾３＋构成的,其中Ｙｂ＾３＋和Ｔｍ＾３＋替代部分Ｐｂ＾２＋的格位而形成了荷正电的局域杂质中心。这些局域杂质中心导致了ＰｂＦ２＋ＷＯ３＋ＧｅＯ２＋ＹｂＦ３＋ＴｍＦ３中局域电场的形成。除了     

Algebraic Description of Anharmonic Stretching Vibrations

A U(2) algebraic model is presented to describe stretching vibrations of XYn (n = 2, 3, and 4) systems, where anharmonic interactions between the bond modes are considered. This model in a limit corresponds to an anharmonically coupled local-mode model. As an example, the model for a molecule XY4 is applied to recently observed spectra of methane in both gas and liquid phases, and the results obtained are in good agreement with the experiments. Copyright 1999 Academic Press.     

Fermi Resonances and Vibrational Spectrum of a Polyatomic Molecule XY4: an Algebraic Approach

A U(2) algebraic model is introduced for the spectrum of a molecule XY₄, where the interactions between the stretch and bend modes are described by T_d symmetric Fermi resonance terms. The presented algebraic model in a limit corresponds to another model in recent literature. The vibrational spectrum of methane (CH₄) measured recently with modern spectroscopy techniques is employed to test those models. The obtained standard deviation between the observed and the calculated vibrational energy levels in the algebraic model is smaller than that in the corresponding model.     

Stretching excitations of tetrahedral molecules in an anharmonically coupled local mode model

Summary  An anharmonically coupled local mode model is used to study highly excited stretching vibrational spectra and intensities of infrared transition in a tetrahedral molecule. This model is successfully applied to silane and silicon tetrafluoride. The author is very grateful to Prof. Zhong-Qi Ma for his continuing interest, support and sound advice. This work was supported by the National Natural Science Foundation of China and Grant No. LWTZ-1298 of the Chinese Academy of Sciences.     

Coriolis interaction in the local mode (n100;F2) combination states of GeH4

Coriolis interactions in local mode (n100) combination states of GeH₄ are studied. Three widely used local mode models, the normal mode model with Darling–Dennison resonance included (NMDD) model and the anharmonically coupled anharmonic oscillator (ACAO) model with two different kinds of bond stretching variable, were used to calculate the values of the interaction parameters. As a test of these three models, the Coriolis interaction parameters of the local mode (3100) combination bands of the ⁷⁴GeH₄,⁷²GeH₄ and ⁷⁰GeH⁴ species, recorded at a resolution of 0.015cm^-1 on a Bruker IFS120HR Fourier transform spectrometer, are compared with the calculated results. There is good agreement.     

H2O分子OH键振动能谱的代数计算

用U(2)代数模型,对H2O分子OH键的高激发振动能谱进行了理论计算,并与其它模型的计算相比较,结果表明,代数模型能以较小的标准偏差描述这一分子OH键的振动能谱。     

U (2) algebraic model applied to vibrational spectra of Nickel Metalloporphyrins

In this paper the highly excited stretching and bending vibrational energy levels of some Nickel Metalloporphyrin molecules are studied by U (2) algebraic model. Its application to Nickel Octaethyl Porphyrin, Nickel Tetra Phenyl Porphyrin and Nickel Porphyrin are presented with fewer algebraic fitting parameters. The highly excited stretching and bending vibrational energy levels of these molecules are showing the energy clustering spectrum.     

Temperature dependence of the vibrational lineshape of CO chemisorbed on the Ni(111) surface

The lineshape of the carbon-oxygen stretching vibration for CO chemisorbed at the two-fold bridge sites and on top sites of Ni(111) has been measured over the temperature range 80 to 300 K with infrared reflection absorption spectroscopy. The bridge bonded CO undergoes pronounced broadening at higher temperatures while the terminally bonded CO is only slightly broadened. The results are interpreted according to a recent vibrational dephasing model developed for condensed phase molecules. In this model the dephasing is brought about by rapid energy exchange between low frequency modes of the substrate and low frequency modes of the molecule which are anharmonically coupled to the high frequency band being studied.     

Algebraic vortex liquid in spin-1/2 triangular antiferromagnets: scenario for Cs2CuCl4

Motivated by inelastic neutron scattering data on Cs2CuCl4, we explore spin-1/2 triangular lattice antiferromagnets with both spatial and easy-plane exchange anisotropies, the latter due to an observed Dzyaloshinskii-Moriya interaction. Exploiting a duality mapping followed by a fermionization of the dual vortex degrees of freedom, we find a novel critical spin-liquid phase described in terms of Dirac fermions with an emergent global SU(4) symmetry minimally coupled to a noncompact U(1) gauge field. This "algebraic vortex liquid" supports gapless spin excitations and universal power-law correlations in the dynamical spin structure factor which are consistent with those observed in Cs2CuCl4. We suggest future neutron scattering experiments that should help distinguish between the algebraic vortex liquid and other spin liquids and quantum critical points previously proposed in the context of Cs2CuCl4.     

Exact Solutions of Two Coupled Harmonic Oscillators Related to the Sp（4,R） Lie Algebra

Exact solutions of the eigenvalue problem of two coupled harmonic oscillators related to the Sp(4,R) Lie algebra are derived by using an algebraic method. It is found that the energy spectrum of the system is determined by one-boson excitation energies built on a vector coherent state of Sp(4,R)\supset U(2).     

Mode coupling and the pressure induced phase transition in thallium azide (TlN3)

A Raman scattering study of the pressure induced phase transition in thallium azide is discussed. The transition appears to be triggered by the softening of a mode at 33 cm^?1, which is shown by a Green's function calculation to be anharmonically coupled to another mode of the same symmetry at 48 cm^?1.