PuH2分子的分析势能函数研究

在相对论有效原子实势近似下,用B3LYP密度泛函方法计算优化出PuH2分子基态的结构参数,离解能和力常数。采用多体展式方法,导出PuH2分子基态(X7A1)的分析势能函数,获得的势能面正确地复现出PuH2分子的平衡结构特征。     

PuH和PuH2的分子结构与分子光谱

采用密度泛函B3LYP方法计算给出了H系元素Pu的氢化物PuH(X8Σ-)基态分子结构与光谱数据, 以及Murrell-sorbie势能函数. 对于PuH2分子的计算表明, 其基态为C2v结构, 电子状态为X7B1, 计算同时也给出了平衡结构和光谱数据, 并拟合得到其全空间多体展式解析势能函数.     

PuH分子的X~8Σ~+ 态的势能函数及热力学函数的从头计算

在考虑相对论有效原子实势(RECP)近似下,用QCISD方法计算了PuH分子基态X8Σ+的MurrellSorbie解析势能函数和热力学函数。Re,De,Be,αe,ωe,ωeχe的理论计算值,分别为2.28,1.2227eV,3.2334,0.07742,1146.2632,24.7514(cm-1)。还给出了PuH(g)在298.15-911K之间的生成热力学函数ΔH0,ΔS0,ΔG0和Cp的计算值     

PuH分子的X~8Σ~ 态的势能函数及热力学函数的从头计算

在考虑相对论有效原子实势(RECP)近似下,用QCISD方法计算了PuH分子基态X8Σ 的MurrellSorbie解析势能函数和热力学函数。Re,De,Be,αe,ωe,ωeχe的理论计算值,分别为2.28,1.2227eV,3.2334,0.07742,1146.2632,24.7514(cm-1)。还给出了PuH(g)在298.15-911K之间的生成热力学函数ΔH0,ΔS0,ΔG0和Cp的计算值     

AlB2和Al2B的结构与解析势能函数

运用单双取代耦合簇(CCSD)方法,选择基组6-311+g(2df)对基态B2、Al2分子和基组6-311g(3df)对基态AlB分子的微观结构进行优化计算,采用最小二乘法拟合得到B2、Al2和AlB分子的势能函数,并得到了与实验值符合很好的光谱常数.采用同种方法,选择6-31g基组,对基态AlB2和Al2B分子的结构进行优化计算.运用原子分子反应静力学原理得到离解极限.在此基础上,采用多体项展式法,得到AlB2和Al2B分子基态解析势能函数,该势能函数准确再现了AlB2和Al2B分子基态平衡结构特征.     

PuHn+(n=1,2,3)分子离子的势能函数与稳定性

用密度泛函B3LYP方法对PuHn (n =1,2 ,3)分子离子进行了理论研究 .结果表明 ,PuH ,PuH2 分子离子能稳定存在 ,基态电子状态是X7Σ-(PuH )和X8Σ-(PuH2 ) ,并导出了相应的几何性质、力学性质和光谱数据 .PuH3 ( 7Σ-)分子离子不能稳定存在 .     

基态Li_n(n=2,3)结构与完全解析势能函数

使用Gaussian03程序包,采用全电子单双取代耦合簇(CCSD(full))方法,选择基组6-311+g(2df),对Li2分子的基态进行优化计算,采用十一参量Murrell-Sorbie函数,运用最小二乘法拟合得到Li2分子基态解析势能函数,给出与实验值符合很好的光谱常数;使用同样的方法和基组,对Li3分子的基态结构进行优化计算,得到Li3分子基态平衡结构.采用多体项展式法,利用Li3分子平衡结构C2v的几何参数、力常数和离解能,以及七个线性系数Ci(i=1,2,3,4,5,6,7)与两个非线性系数的函数关系,进行非线性优化拟合得到两个非线性系数,进而得到七个线性系数,得到Li3分子基态完全解析势能函数.势能面静态特征表明,该势能函数再现了Li3分子基态全部平衡结构特征.     

基态Bn(n=2,3)结构与完全解析势能函数简

使用Gaussian03程序包,采用全电子单双取代耦合簇(CCSD(full))方法,选择基组6-311+g(2df),对B2分子的基态进行优化计算,采用十一参量Murrell-Sorbie函数,运用最小二乘法拟合得到B2分子基态解析势能函数,给出与实验值符合很好的光谱常数;使用同样的方法和基组,对B3分子的基态结构进行优化计算,得到B3分子基态平衡结构.采用多体项展式法,利用B3分子平衡结构C2v的几何参数、力常数和离解能,以及七个线性系数Ci(i=1,2,3,4,5,6,7)与两个非线性系数的函数关系,进行非线性优化拟合得到两个非线性系数,进而得到七个线性系数,得到B3分子基态完全解析势能函数.势能面静态特征表明,该势能函数准确再现了B3分子基态全部平衡结构特征.     

用ab initio方法计算NaLi分子基态(X1∑+)的势能函数及光谱常数

运用原子分子群表示方法,首先确定NaLi分子的电子基态(X1∑ ).然后选用6-311 G(3df,2pd)基组优化计算得到NaLi分子基态(X1∑ )的平衡结构和离解能,采用电子相关QCISD(T)方法结合6-311 G(3df,2pd)基组对NaLi分子基态进行单点能扫描计算.最后用单点扫描计算值结合优化计算所得参数去拟合Murrell-Sorbie函数,得到了NaLi分子基态的势能函数.用该势能函数计算的光谱常数与实验结果符合得很好,表明拟合确定的势能函数能精确地描述基态NaLi分子的结构和性质.     

LiB2和Li2B分子的结构与势能函数

运用单双取代耦合簇(CCSD)方法,选择基组6-311+g(2df)对基态B2、Li2和LiB分子的微观结构进行优化计算,采用最小二乘法拟合得到B2、Li2和LiB分子的势能函数,并得到了与实验值符合很好的光谱常数.采用同种方法,选择6-311g基组对LiB2、6-31g基组对Li2B分子的基态结构进行优化计算.运用原子分子反应静力学原理得到离解极限.在此基础上,采用多体项展式法,得到LiB2和Li2B分子基态解析势能函数,该势能函数准确再现了LiB2和Li2B分子基态平衡结构特征.     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.     

Single-beam self-referenced phase-sensitive surface plasmon resonance sensor with high detection resolution

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance(SPR)sensing system with ultra-high resolution performance is presented.The system exhibits a root-mean-square phase fluctuation of ±0.0028.over a period of 45 min.i.e.a resolution of±5.2×10-9 refractive index units.The enhanced performance has been achieved through the incorporation of three design elements:a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected,a differential measurement scheme to eliminate spurious signals not related to the sensor response,and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulato .Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.     

Influences of SiO2 protective layers and annealing on the laser-induced damage threshold of Ta2O5 films

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition.The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated.The results show that SiO2 protective layers exert little influence on the electric field intensity(EFI)distribution,microstructure and microdefect density but increase the absorption slightly.Annealing iS effective on decreasing the microdefect density and the absorption of the films.Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT.Moreover,the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.     

A stereo matching algorithm using multi-peak candidate matches and geometric constraints

Gray cross correlation matching technique is adopted to extract candidate matches with gray cross correla- tion coefficients less than some certain range of maximal correlation coefficient called multi-peak candidate matches. Multi-peak candidates are extracted corresponding to three closest feature points at first. The corresponding multi-peak candidate matches are used to construct the model polygon. Correspondence is determined based on the local geometric relations between the three feature points and the multi-peak candidates. The disparity test and the global consistency checkout are applied to eliminate the remaining ambiguous matches that are not removed by the local geometric relational test. Experimental results show that the proposed algorithm is feasible and accurate.