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2002年  第19卷  第2期

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论文
Xe I原子6s[3/2]2亚稳态寿命的理论研究
董晨钟, 颉录有, Stephan Fritzsche
2002, 19(2): 81-84. doi: 10.11804/NuclPhysRev.19.02.081
摘要:
利用多组态Dirac Fock(MCDF)理论方法 ,系统地研究了延迟和相关效应对中性XeI原子5p56s[3/ 2 ]2—5p61S0 (M2 )辐射跃迁的影响 ,给出了亚稳态 6s[3/ 2]2的辐射寿命.与最新的磁光阱实验观测结果比较,目前的计算不仅大大提高了理论计算的精度 ,而且解释了实验和以往理论偏差非常大的原因. The recent high precision measurement on the lifetime of metastable 6s state of atomic xenon shows a difference with previous prediction by a factor of 2-3. In the present work, a new theoretical method which can systematically treat relaxation and correlation effects on the basis of the MCDF method is used to study the M2 transitions between the 5p 56s and 5p 6 configurations. By including the correlation contributions of the single and double excitations from the 5l subshells...
Mo XIV离子精细结构能级和辐射寿命
王晓东, 姜仁滨, 裴东, 王宛珏
2002, 19(2): 85-90. doi: 10.11804/NuclPhysRev.19.02.085
摘要:
用全相对论多组态自洽场方法 ,计算了类铜离子MoXIV的 1s ,2s ,2p- ,2p ,3s,3p- ,3p ,3d- ,3d ,4s,4p- ,4p ,4d- ,4d ,4f- ,4f,5s,5p- ,5p ,5d- ,5d ,5f- ,5f ,5g- ,5g ,6s,6p- ,6p ,6d- ,6d ,6f- ,6f,6g- ,6g ,6h- ,6h ,7s,7p- ,7p ,7d- ,7d ,7f- ,7f,7g- 和 7g轨道的 15 0 8个精细结构能级和辐射寿命以及其它各种跃迁参数 ,能级的计算值和实验值符合得很好 .另外还发现了一些寿命较长的能级. Energy levels, radiative lifetime and various transition parameters for allowed transitions among the 1 508 fine-structure levels belong to the (1s 22s 22p 63s 23p 6) 3d 104l, 3d 94l 2, 3d 105l, 3d 94l4m, 3d 106l, 3d 107l and so on configurations of the Cu-like ions Mo XIV have been calculated by using the expanded fully relativistic GRASP code. The results are compared with those available in the literature, and the accuracy of the present data is assessed. En...
双原子分子体系的振动结构研究
孙卫国, 侯世林, 冯灏, 任维义
2002, 19(2): 91-94. doi: 10.11804/NuclPhysRev.19.02.091
摘要:
最近通过微扰理论得到了双原子分子体系的能量表达式、振动光谱常数和转动光谱常数 ,并建议用代数方法和势能变分法由有限的振动能级求得收敛的振动能级的完全谱和高阶的振动力常数 .用该方法对一些双原子分子电子态的计算结果表明 :(1)代数方法得到的最高振动能收敛于正确的分子离解能 ;(2 )代数方法产生的振动能级不但能重复已知的精确能级 ,而且还能得到实验上和其他理论方法难以得到的高振动激发态的能级 ;(3)可用获得的各阶振动力常数fn比较同一分子的不同电子态的化学键的相对强度. Alternative expressions for vibrational and rotational spectrum constants and energies of diatomic molecular electronic states are suggested based on the perturbation theory. An algebraic method (AM) is proposed to generate converged full vibrational spectrum from limited energy data, and a potential variational method (PVM) is suggested to produce the vibrational force constants f n s and rotational spectrum constants using the perturbation formulae and the AM vibrational constants. Applying this method...
铍原子的能级和超精细结构的研究
王菲, 苟秉聪, 俞开智
2002, 19(2): 95-97. doi: 10.11804/NuclPhysRev.19.02.095
摘要:
采用多组态相互作用方法及Rayleigh Ritz变分法 ,并考虑相对论修正、质量极化效应等 ,获得了铍原子低激发态 1s2 2s2p3 Po和 1s2 2p2 3 P高精度的相对论能量 .同时还计算了铍原子超精细结构常数 ,与其他理论和实验结果符合得很好. The Rayleigh-Ritz variational method is used with a multiconfiguration-interaction function and restricted variation method to obtain the relativistic energies of 1s 22s2p 3P o and 1s 22p 2 3Pin beryllium, including the mass polarization and relativistic corrections. Hyperfine structure is also studied to compared with theoretical and experiment data in the literature.
由基样条构造有限基集计算的超精细结构常数(英文)
吴礼金, 李勇, 高克林
2002, 19(2): 98-102. doi: 10.11804/NuclPhysRev.19.02.098
摘要:
多体微扰论有效算符方法应用于超精细结构的计算 .由HF波函数计算零阶超精细常数 .使用基样条构造了薛定谔方程的有限基集 .使用这些有限基集计算了原子实极化和关联 ,以及 7Li,2 3 Na ,3 9K和4 3 Ca离子的s1/ 2 ,p1/ 2 和p3 / 2 态的超精细结构常数和4 3 Ca离子的d3 / 2和d5/ 2 态的超精细常数 . The effective-operator form of many-body theory is applied to the calculation of hyperfine structure. The zeroth order hyperfine constants are evaluated with Hartree-Fock wavefunction. Τhe finite basis sets of Schrdinger s equation are constructed by using B-splines. With the finite basis sets, we have calculated the core polarization, and the correlation diagrams. The hyperfine constants of the s 1/2, p 1/2and p 3/2 states of 7Li, 23Na, 39K, 43Ca + as well as the d 3/2...
非线型三原子分子势能面的Lie代数方法
丁世良, 冯东太, 郑雨军
2002, 19(2): 103-106. doi: 10.11804/NuclPhysRev.19.02.103
摘要:
利用Lie代数方法得到三原子分子的代数Hamiltonian ,通过对光谱数据的拟合确定其展开系数 ,再用相干态得到代数Hamiltonian的经典极限 ,从而得到三原子分子的势能面 .以H2 O分子为例进行了计算 ,其理论值与实验结果一致. The algebraic Hamiltonian for a triatomic molecule can be obtained by using dynamical Lie algebra method (the expansion coefficients are obtained by fitting spectroscopic data). Triatomic molecular potential energy surface (PES) is obtained by using coherent state to take the classical limits of algebraic Hamiltonian. This PES is applied to H 2O molecule, and the deduced force constant is in good agreement with the experimental data.
N II离子禁戒跃迁几率的理论计算
袁萍, 颉录有, 刘欣生, 张树东, 董晨钟
2002, 19(2): 107-109. doi: 10.11804/NuclPhysRev.19.02.107
摘要:
用多组态Dirac Fock方法 ,系统考虑了相对论效应、电子关联、延迟效应等重要贡献 ,计算了NII离子 2p3d— 2p2 以及 2p3d— 2p3p (ΔL =± 2 ,ΔS =± 1)禁戒跃迁的几率 .与已有的理论相比 ,目前计算的精度有了明显提高. The forbidden transition probabilities have been calculated for the 2p3d -2p 2 and 2p3d-2p3p(ΔL=±2, ΔS=±1) spectra of N II by using a large-scale multiconfiguration Dirac-Fock (MCDF) method. The most important effects of relativity, correlation, and relaxation are considered in the calculation Comparing with other calculations, a remarkable improvement is achieved.
环戊烷分子的1e1轨道电子密度
李桂琴, 邓景康, 王芳, 张弢, 宁传刚, 王岩, 郑延友
2002, 19(2): 110-112. doi: 10.11804/NuclPhysRev.19.02.110
摘要(1313)
摘要:
从实验和理论上研究了环戊烷分子的 1e″1轨道电子动量谱分布 .理论计算采用Hartree Fock方法和密度泛函理论 ,给出了该轨道的位置空间的密度分布图 .对环戊烷分子的电子动量谱研究在国内首次将分子样品的研究由气态扩展到了液态. The spherically averaged momentum distributions for cyclopetane have been investigated by experimental measurements and theoretical calculations. Theimpact energy is 1 200 eV plus binding energy and a symmetric non-coplanar kinematics is employed. The theoretical calculations are obtained by using Hartree-Fock method and Density Function Theory. The position density for 1e ″ 1 orbital is reported.
LaF分子结构与基态X1Σ+势能曲线研究
陈林红, 尚仁成
2002, 19(2): 113-116. doi: 10.11804/NuclPhysRev.19.02.113
摘要:
用能量一致相对论有效核芯势和含极化函数 4f2g和弥散函数 1s1p1d的价基组 ,在各种计算水平上计算了LaF分子结构、振动频率和离解能 .根据原子分子反应静力学原理导出LaF分子基态可能的电子状态和离解极限 ,用密度泛函理论中的B3LYP方法计算了基态X1Σ+ 势能曲线 ,拟合得到了Murrell Sorbie解析势能函数及其在平衡位置附近的Dunham展开式 ,由此计算的振转常数和实验光谱数据完全吻合 .得到的解析势能函数可用于计算振转光谱精细跃迁结构和原子分子碰撞反应动力学过程 ,具有重要的实用意义 . The equilibrium geometry, harmonic frequency and dissociation energy of the molecule LaF have been calculated on several kinds of computation levels with energy-consistent relativistic effective core potentials and valence basis sets including polarization functions 4f2g and diffuse functions 1s1p1d. The possible electronic state and its reasonable dissociation limit for the ground state of LaF are determined based on Atomic and Molecular Reaction Statics(AMRS). The potential energy curve scan for...
溴的类镁离子跃迁谱线和能级扩展分析
杜树斌, 江历阳, 李景文, 陈华中, 曾宪堂, 刘惠萍, 马新文, 王友德
2002, 19(2): 117-121. doi: 10.11804/NuclPhysRev.19.02.117
摘要:
用中国原子能科学研究院HI 13串列加速器提供的 90和 130MeV的Br离子和束箔技术 ,研究了波长在 13— 2 9nm范围内Br的类Mg离子的光谱 .识别出 2 4条属于BrXXIV的“3,3”跃迁 ,即 3s2 ,3s3p ,3p2 ,3s3d和 3p3d组态之间的跃迁谱线 ,其中 19条以前未见报道 .基于实验跃迁谱线 ,19个观测能级得以确立 ,其中有 14个能级此前未见报道 .相对论Hartree Fock(HFR)方法的计算结果对所观测的能级进行了解释.The spectrum of Mg-like Br, Br XXIV is investigated by means of beam-foil technique. Bromine ions of 90 and 130 MeV energy from the HI-13 tandem accelerator are used, and the wavelength region 13-29 nm is investigated. In the spectra, 24 Br XXIV transitions within the n=3 complex, i.e. between the 3s 2, 3s3p, 3p 2, 3s3d and 3p3d configurations are identifies, among them 19 have not been reported before. Based on these transition lines 19 energy levels have been determined and 14 energy level...
类铍硫n=2的某些能级寿命的实验研究
杨治虎, 马新文, 刘惠萍, 王友德, 苏弘, 肖国青
2002, 19(2): 122-124. doi: 10.11804/NuclPhysRev.19.02.122
摘要:
主要报导用束箔技术对天体等离子体中重要元素硫的高电离态原子n =2的某些能级寿命的实验测量.实验数据用CANDY程序分析 ,并与理论计算结果和其它的实验结果作了比较. Lifetime measurement has been carried out for some low lying n=2 levels in the four electron ions S ⅩIII by using the beam-foil technique at National Laboratory of Heavy Ion Accelerator, Lanzhoiu, China. Spectra of highly ionized sulfur obtained at an energy of 2.5 MeV/nucleon have been studied in the 190-530  wavelength range. Experimental decay curves are analysized by the CANDY program, and compared with theoretical calculations and experimental measureaments.
C2H4价壳层电离连续区光解离研究
钟志萍, 韩小英, 李家明
2002, 19(2): 125-127. doi: 10.11804/NuclPhysRev.19.02.125
摘要:
在量子数亏损框架下,利用多重散射自洽方法计算了C2 H4 价壳层电离连续区光吸收谱.通过对势形共振的峰位分析,探讨了势形共振对光解离动力学的影响. The photoabsorption spectra in the valence-shell continuum region of C 2H 4 are calculated by the multi-scattering self-consistent-field method in the framework of the quantum defect theory. The energy positions of potential shape resonance are determined. The influence of the potential shape resonance on photodissociation dynamics is discussed.
能量ε<0时Li原子在平行电磁场中的光吸收谱研究
宋晓红, 林圣路
2002, 19(2): 128-130. doi: 10.11804/NuclPhysRev.19.02.128
摘要:
利用包括实散射的闭合轨道理论和分区自洽的迭代算法,计算了标度能量为ε =- 0 .0 3,标度电场F =0 .0 1时的平行电磁场中n≈ 4 0 ,m =0的Li原子闭合轨道以及光吸收谱.介绍了谱的标度特性 ,它对理解量子与经典之间的对应关系具有非常重要的意义.并与同样情况下的氢原子谱作了比较 .验证了离子实对光吸收过程的重要作用. By employing the semiclassical closed-orbit theory including core-scattering and region-splitting consistent iterative method, we calculate the closed-orbits and the recurrence spectra of n≈40, m=0 Li Rydbergatom in parallel electric and magnetic fields at scaled energy ε=-0.03. The constant scaled electric field is =0.01 . The novel spectral structures are compared with those of hydrogen obtaines by standard closed orbit theory. The effect of the core-scattering has been discussed.
类氢铀离子的辐射电子俘获角分布研究
马新文, T.Sthlker, H.F.Beyer, F.Bosch, O.Brinzanescu, C.Kozhuharov, P.H.Mokler, T.Ludziejewski, Z.Stachura, A.Warczak
2002, 19(2): 131-135. doi: 10.11804/NuclPhysRev.19.02.131
摘要:
分析了在重离子冷却储存环上测量的辐射电子俘获产生的X射线能谱,得出了K REC光子的相对微分角分布,通过与非相对论理论和全相对论理论的计算结果进行比较,从实验上证明了相对论重离子 原子碰撞中自旋翻转跃迁的存在,实验结果与全相对论理论计算结果一致.同时还证实,重离子体系本身的相对论性质对碰撞过程有重要影响. Radiative electron capture process occurring in high-Z ion-atom collisions studied on the heavy ion storage ring (ERS) is reviewed. The REC differential angular distributions are deduced from the X-ray spectra recorded at various observation angles for 310 and 88 MeV/u U 92+on N 2collisions, respectively. The experimental results are compared with non-relativistic and complete relativistic calculations. Deviations from sin 2θ lab are found in both cases. The contributions to near 0°observation...
离子和冷却电子重组的高分辨谱研究(英文)
R. Schuch, N. Eklw, M. Fogle, E.Lindroth, S. Madzunkov, T. Mohamed, D. Nikolic, P.Glans, H. Danared, A. Kllberg, A. Paal
2002, 19(2): 136-139. doi: 10.11804/NuclPhysRev.19.02.136
摘要:
给出了在CRYRING重离子储存环上测量到的在很低能量下电子与离子重组的最新实验结果和有关速率系数增强的新的数据 .主要讨论类锂、类钠和类铜离子的共振双电子重组的新近测量结果 ,以及从这些共振谱中所导出的非常精确的离子能级劈裂值 ,从而将严格检验相对论效应、电子关联效应和量子电动力学效应 .其中 ,对类锂Kr3 3 + 离子 2s1/2 能级Lamb移位的确定精度达到了0 .1%. We present our latest results on recombination of electrons with ions at very low energies obtained at the CRYRING heavy-ion storage ring. New data on the enhanced rate coefficient are shown. Then we concentrate on recent measurements of dielectronic recombination resonances with Li-like, Na-like, and Cu-like ions, where from the spectra of resonances very accurate values for energy splittings are derived for crucial tests of relativistic, correlation, and QED effects.
低能电荷转移截面和高能转移电离研究(英文)
C.D.Lin, Teck Lee, T.Y.Shi
2002, 19(2): 140-143. doi: 10.11804/NuclPhysRev.19.02.140
摘要:
介绍了对于Na+ 离子和Rb(5s ,5p)原子碰撞中态选择单电子俘获微分截面的理论计算,并与实验数据进行比较,实验结果是离子与在磁光学阱中用激光冷却的碱金属靶原子碰撞而测量到的;还对高能量质子引起的He原子的转移电离进行了理论研究,在Shakeoff模型的基础上 ,分析解释了转移电离截面与单电子俘获截面的比值 ,并与最新实验结果作了比较. We report a theoretical study of state-selective differential single-electron capture cross sections between Na + and Rb(5s, 5p) atoms. The experimental data have been obtained with laser cooled target in a magnetic optical trap. We also report a theoretical study of transfer ionization of He by protons at high collision energies and analyze the transfer ionization cross section with respect to single electron capture cross section in terms of a shakeoff model.
电子与多电荷离子的碰撞电离(英文)
K.Aichele, W.Arnold, D.Hathiramani, F.Scheuermann, E.Salzborn
2002, 19(2): 144-146. doi: 10.11804/NuclPhysRev.19.02.144
摘要:
主要揭示了不同电离机制对高电荷态离子单电离和多重电离的贡献 ,包括直接电离 (一步过程 )、激发 自电离 (两步过程 )以及内壳Auger过程 ,研究了高电荷态镨离子的电子碰撞电离. Electron-impact ionization of ions is one of the most fundamental processes in every kind of plasma. Especially in high-temperature plasmas-whether in laboratory (nuclear fusion) or in astrophysics (atmosphere of stars)-atoms become ionized into multiply-charged ions by electron impact. The main purpose of our investigations is to unravel the contributions from different ionization mechanisms-like direct ionization (one-step process), excitation-autoionization (two-step process) and...
Ar (e ,3e)实验中TS2机制的明显证据(英文)
贾昌春, A.Lahmam-Bennani, A.Duguet, L.Avaldi, M.Lecas, C.Dal Cappello
2002, 19(2): 147-149. doi: 10.11804/NuclPhysRev.19.02.147
摘要:
通过比较Ar在低碰撞能量下的 (e ,3e)双电离实验结果和基于包含一次作用机制SO和TS1的一阶波恩近似的理论计算结果 ,表明在动量转移方向上对称性的破坏显示非一次效应 (例如二型两步作用机制 )起非常重要的作用. Through comparing the Ar (e,3e) double ionization experimental results at low collision energy with the theoretical calculation based on the first Born approximation which include the first order mechanisms SO and TS1, the symmetry breaking about the direction of the momentum transfer shows that the non-first order effects (such as two-step 2 mechanism) play an important role.
微分散射截面测量中气压效应的修正
朱林繁, 刘小井, 李文斌, 苑震生, 成华东, 钟志萍, 徐克尊
2002, 19(2): 150-152. doi: 10.11804/NuclPhysRev.19.02.150
摘要:
介绍了微分散射截面测量过程中的气压效应 ,通过深入分析得出了二次散射系数E(θ)与零度角的强度A0 成正比 ,随散射角θ的增加而增加以及它的值可正可负 .通过与实验的对比 ,证实了前两条结论 ,并指出可把该结论用于指导实验. The pressure effect for the measurement of differential cross section is introduced and analysed in detail. Three conclusions are obtained: the double scattered coefficient E(θ) is proportional to the strength A 0 of the excitations measured at 0°; E(θ) increases with the increasing of scattered angle; the values of E(θ) can be positive or negative. The front two conclusions are tested by experiment, and it is pointed that they are helpful to the measurement of differential cross section.
电子碰撞电离截面的全相对论扭曲波计算
陈重阳, 赵永, 齐静波, 王炎森
2002, 19(2): 153-156. doi: 10.11804/NuclPhysRev.19.02.153
摘要:
在相对论框架下 ,给出了电子与高电荷态离子碰撞直接电离截面的扭曲波玻恩交换近似计算方法 .作为示例 ,计算了几个离子 (类氢、类锂和类氖离子 )的电离截面 ,计算结果与实验值和其它理论计算值有比较好的符合. A fully relativistic distorted-wave exchange approximation method is presented. It can be used to obtain electron impact ionization cross section of highly charged ions. The ionization cross sections of several H-, Li, and Ne-like ions have been calculated. Good agreement is obtained while the calculated values are compared with the experiments or other relativistic calculations.
碱金属团簇Na2在重离子作用下的离化
魏宝仁, 张丰收, 马新文, 王锋
2002, 19(2): 157-160. doi: 10.11804/NuclPhysRev.19.02.157
摘要:
在时间相关的局域密度近似理论框架下研究了重离子Ar8+ 和碱金属团簇Na2 随时间演化的相互作用 .给出了电子系统的总能量 ,产生Na2 的各种电荷态的几率和Na2 价电子的平均逃逸数等物理量随时间的演化 ,进而得到了Na2 的离化几率 .在快重离子与团簇作用中 ,可以得到低激发态的团簇离子. Based on the Time Dependent Local Density Approximation(TDLDA), the processes of excitation of sodium clusters by highly charged Ar 8+ions are simulated. The time-dependent probabilities of escaped electrons are obtained, furthermore, the ionization probabilities of the Na 2clusters are deduced.In fast ion-cluster collisions, Na 2cluster ions can be produced with minimum or even no excitation of the cluster itself
非平衡等离子体中原子过程的计算
吴泽清
2002, 19(2): 161-164. doi: 10.11804/NuclPhysRev.19.02.161
摘要:
为得到由中、高Z元素形成的非局域热动平衡等离子体中的离子丰度分布的可靠信息 ,对建立速率方程所需的各种离子的各个原子过程采用了基于一级微扰论的计算 ,提高了原子参数的精度 ;为了进一步节省计算时间 ,在保证精度的前提下 ,针对不同的过程做了不同的近似处理 ;对各个原子过程的计算结果进行多方比较,表明精度可靠.
Sr+HF体系的动力学研究
刘玉芳, 孟慧艳, 王永, 朱遵略, 孙金锋
2002, 19(2): 165-168. doi: 10.11804/NuclPhysRev.19.02.165
摘要:
应用扩展的LEPS势能面 ,对处于高碰撞能零振动激发 (Ecol=5 4 .18kJ/mol ,ν =0 ,j=0 )和低碰撞能低振动激发 (Ecol=7.5 6kJ/mol ,ν =1,j=0 )两种初始条件下的Sr+HF体系的竞争反应模式、定态分布函数Pν(b)以及反应碰撞能对产物SrF转动取向的影响进行了准经典轨线计算 ,计算结果与实验结果及相关理论符合得很好 ,且能给予实验以合理的动力学解释 . The quasiclassical trajectory method based on the extended LEPS potential energy surface has been employed here to investigate the reaction mechanism and features in the reaction Sr+HF→SrF+H at two reactional conditions (collision energy E c o l=54.18 kJ/mol, ν=0, j=0 and E c o l=7.56 kJ/mol, ν=1, j=0). The dynamical features in the competitive reaction modes are discussed and the stationary distribution function P ν(b) of the product SrF has already been deduced...
Li-和Na-单电子解离过程的研究
陈熙萌, 吴翠娥, 刘兆远, 于得洋, 祁中, 王强, 杨治虎, 刘惠萍
2002, 19(2): 169-171. doi: 10.11804/NuclPhysRev.19.02.169
摘要:
采用交叉束方法 ,利用负离子源产生的 3— 19keV的Li- 和Na- 轰击惰性气体靶He ,Ne和Ar ,通过静电偏转和位置灵敏探测器区分碰撞后中性粒子束和负离子束 ,测量了不同碰撞系统的中性粒子计数与相应入射负离子计数的比值R(E) ,并得到R(E)与入射负离子能量、负离子种类和靶原子种类的关系. The count ratios R of the neutralized atoms of final state to projectiles Li -and Na -in collision with He, Ne and Ar are measured in the energy range of 3-19 keV. It is found that the count ratios R increase slowly with the collision energy in whole experimental energy range for He, Ne and Ar. For Li -→He, Ne, Ar Collisions, R(He)≈R(Ar)>R(Ne), and for Na -→He, Ne, Ar Collisions, R(He)>R(Ar)> R(Ne).
非全裸氟离子与氖原子碰撞中的转移电离研究
于得洋, 陈熙萌, 杨治虎, 王强, 卢荣春, 刘惠萍, 祁中, 吴翠娥, 蔡晓红, 马新文, 刘兆远
2002, 19(2): 172-175. doi: 10.11804/NuclPhysRev.19.02.172
摘要:
采用位置灵敏探测和散射离子 反冲离子飞行时间技术测量了强相互作用区F2 + 和F3 + 离子与Ne原子碰撞中的转移电离截面与单电子俘获截面之比 .与Fq+ He实验结果进行了比较 ,并进行了定性讨论. The ratios of the cross-section of the transfer ionization to the single electron capture of Neon induced by F 2+ and F 3+ ions are measured by means of the time-of-flight technologie. In the present energy range, the transfer ionization C1I1 of neon can be considered as a two-step process, in which one electron is captured by projectile and another one is directly ionized, and the transfer ionization C1I2 process should be considered as a subsequent rearrangement of neon following...
在ELISA储存环上研究成色基团的光吸收(英文)
L.H.Andersen, A.Lapierre, I.B.Nielsen, S.B.Nielsen, U.V.Pedersen, S.U.Pedersen, S.Tomita
2002, 19(2): 176-179. doi: 10.11804/NuclPhysRev.19.02.176
摘要:
在电子储存环ELISA上研究了气相生物分子的光吸收 .通过研究发现 ,储存时间长并具有合适的粒子探测系统的储存环是进行成色基团光物理研究的理想工具 .讨论了绿色荧光蛋白质(GFP)的光吸收特性 ,并将气相光吸收测量谱与液体中蛋白质和成色基团的吸收形貌进行了比较 ,认为GFP的吸收特性可以归因于成色基团的固有化学性质. Absorption of gas-phase biomolecules has been studied at the electrostatic ion storage ring ELISA. It is demonstrated that the storage ring technique with long storage times and suitable particle detection is ideal for studies of the photo-physics of chromophores. Here we discuss the absorption characteristics of the chromophores of the Green Fluorescent Protein (GFP) and compare our gas-phase absorption measurements with absorption profiles of the protein and chromophores in liquids ...
耦合双原子与非线性相干态相互作用模型的腔场谱
高云峰, 冯健, 史舒人
2002, 19(2): 180-183. doi: 10.11804/NuclPhysRev.19.02.180
摘要:
研究了两个偶极 偶极相互作用的全同二能级原子与高Q腔内非线性相干态光场相互作用过程的腔场谱 .讨论了原子间耦合强度、初始场光子数分布和初始场强度的改变对光谱结构的影响.
稠密、冷铝等离子体的辐射不透明度研究
曾交龙, 靳奉涛, 袁建民
2002, 19(2): 184-187. doi: 10.11804/NuclPhysRev.19.02.184
摘要:
使用细致谱项模型、联合组态相互作用方法和R 矩阵方法计算了处于局域热动平衡条件下的稠密、冷铝等离子体的辐射不透明度 .组态相互作用方法用于获得束缚 束缚吸收截面所需要的偶极跃迁振子强度 ,R矩阵方法用于获得光电离截面 .对于温度在 6— 12eV、密度为 0 .36mg/cm3 的铝等离子体 ,计算得到的吸收系数在波长为 0 .35 1,0 .5 2 7和 1.0 5 4 μm处与实验结果符合较好 ,而温度在 3— 6eV时 ,理论计算比实验结果大. The radiative opacity has been investigated by using detailed term accounting approximation for dense, cold aluminum plasmas under local thermodynamic equilibrium. The configuration interaction scheme has been used to obtain the relevant atomic parameters for bound-bound absorption, such as excitation energies and oscillator strengths. R-matrix method has been used to obtain the photoionization cross sections. For aluminum plasmas of density 0.36 mg/cm 3, temperature of 6-12 eV, the...
丙酮分子在355nm激光作用下的异构化过程
胡湛, 金明星, 刘航, 丁大军
2002, 19(2): 188-191. doi: 10.11804/NuclPhysRev.19.02.188
摘要:
阐述了在 35 5nm激光作用下超声分子束中丙酮分子的两种异构化过程 ,其中一种为此实验条件下首次观测到的丙酮到丙烯醇的异构 .对两种异构化反应分别给出了过程描述.使用氘代丙酮对异构产物的可能性进行了验证 .并通过中间产物的实验结果进一步说明异构过程. Two isomerization processes of acetone molecule in supersonic beams induced by 355 nm laser are discussed. It is the first time to observe the isomerization from acetone to ally alcohol in this experimental condition. The isomerization process is suggested and verified by time of flight mass spectrum experiments of deuterated acetone and a transient product.
Sc原子高激发态理论研究
张新峰, 夏丹, 钟志萍, 彭永伦, 许祥源, 李家明
2002, 19(2): 192-194. doi: 10.11804/NuclPhysRev.19.02.192
摘要:
利用相对论性多通道量子亏损理论计算了Sc的原子里德堡态能级 .计算结果显示 ,由于通道间的相互作用 ,使得光谱非常复杂 ,这与实验测量结果是一致的. The energy levels of Rydberg series of Sc atom have been calculated by Relativistic Multichannel Theory (RMCT). The calculations reveal that the Rydberg spectra are complex due to the channel interactions, which is consistent with the experimental spectra.
激光诱导等离子体中铜原子和铜离子的时空行为
凌浩, 吴嘉达, 应质峰, 孙剑, 许宁, 李富铭
2002, 19(2): 195-198. doi: 10.11804/NuclPhysRev.19.02.195
摘要:
通过光谱观察 ,考察了激光诱导铜等离子体的动力学过程和等离子体成分的时空行为 .不同能量的等离子体粒子 ,产生的机制不同 ,在时空演变过程中显示的行为不同 ,它们受背景气氛的影响也不同.By observing the optical emissions from copper plasma induced by laser ablationof a copper target, the dynamics of the plasma and the temporal and spatial behaviors of the plasma species are examined. The plasma is ignited from target ablation, evolves from the breakdown of the copper vapor to collisions between copper particles and energetic electrons. At the initial stage, the plasma contains large amount of copper ions and high-excited copper atoms, and then evolves to have low-energy copper...
厚透镜近似下激光驻波场中原子动力学研究
何明, 王谨, 詹明生
2002, 19(2): 199-201. doi: 10.11804/NuclPhysRev.19.02.199
摘要:
研究了在厚透镜近似下 ,原子在激光驻波场中的动力学行为 .通过直接演化一维薛定谔方程 ,发现当激光的强度较大时 ,原子束将会聚焦形成几个焦点 .如果激光的强度更大 ,驻波场中的原子将会出现一种“隧道”现象 ,此时 ,原子受一些实验参数 (如焦平面位置、激光强度等 )的影响程度将大大降低 .这种现象有利于提高原子在驻波场中聚焦沉积的效果 . The dynamics of atoms in laser standing wave (SW) in the regime of over-focused immersion-lens is studied. Through directly evolving a one-dimensional Schrdinger equation, we find that multiple focusing appears when laser intensity is larger than that required for simple focusing. If laser intensity is much higher than that for the single focusing, a "channeling" phenomenon appears, which is insensitive to the variation of some parameters, such as focal plane position and laser intensity...
量子干涉效应对原子共振荧光非经典特性的影响
高韶燕, 李福利
2002, 19(2): 202-205. doi: 10.11804/NuclPhysRev.19.02.202
摘要:
研究了两个自发辐射路径之间的量子干涉效应对V型三能级原子压缩谱和光子反聚束效应的影响 .结果表明 ,量子干涉可以加强压缩效应和展宽出现压缩的相位角分量的范围 ,但却会减弱反聚束效应.Phase-dependent squeezing spectrum and photon antibunching of resonance fluorescence from a three-level V-type atom driven by a coherent field are investigated. We show that for weak excitation intensities quantum interference can greatly enhance squeezing and change the phase quadrature at which the maximum squeezing occurs. We also notice that the maximum squeezing can appear not only in either the in-phase or the out-of-phase quadrature but also in any phase quadrature, and at which phase quadrature...
气压对激光烧蚀Al等离子体中粒子速度的影响
张树东, 陈冠英, 刘亚楠, 董晨钟
2002, 19(2): 206-208. doi: 10.11804/NuclPhysRev.19.02.206
摘要:
在背景气压为8× 10-3— 100Pa范围内 ,通过测量脉冲激光烧蚀平面Al靶产生的等离子体辐射谱的时间分辨特征 ,比较空间不同点辐射的飞行时间轮廓的相对延迟 ,从而得到辐射粒子速度及其空间分布 .利用绝热膨胀的理论和激波模型分别对背景气压小于 0 .6Pa的结果和 5Pa时的结果作了分析 ,并得出激波的波面基本上为柱对称. With the ambient gas pressure in the range from 8×10 -3 to 10 2 Pa, Q-switched YAG laser ablates plane aluminum target and plasma are produced. Optical emission spectroscopy is used to carry out time-resolved analysis of atomic particles. Using the resonance transition of Al I 396.1 nm (3p 2P-4s 2S), the spatiol velocity distribution of Al I has been obtained under the laser energies of 160 mJ/pulse when the ablating size is about 200 μm. The velocity is at the order of 10 6 cm/s...
甲烷在[WO4]中心活化的分子轨道研究
陈宏善, 李树本, 牛建中
2002, 19(2): 209-212. doi: 10.11804/NuclPhysRev.19.02.209
摘要:
利用密度泛函方法研究了Mn -Na2 WO4 /SiO2 催化剂表面的活性中心结构 .对不同活性中心电子结构的分析表明 ,以单个桥氧担载的四面体 [WO4 ]是最可能的甲烷活化中心 ;计算所得活化能为 6 7kJ/mol. By using ab initio DFT method, the metal species formed over the silica surface on Na-W-Mn/SiO 2are optimized, the electronic structure of the catalyst and the activation process of methane is studied. The silica support in the catalyst exists as α-cristobalite and its (111) face exposes preferentially to the surface. Over the surface of α-cristobalite, tungsten existed as monografted tetrahedral \ at the optimal loading amount, and manganese exists in monografted sites or oxide clusters...
共振相干激发的最新实验研究(英文)
Toshiyuki Azuma, T.Ito, Y.Takabayashi, C.Kondo, K.Komaki, Y.Yamazaki, E.Takada, T.Murakami
2002, 19(2): 213-217. doi: 10.11804/NuclPhysRev.19.02.213
摘要:
在满足沟道效应条件下 ,高能离子在穿过晶体时 ,离子穿过的是周期性的原子序列或者有序平面阵列 .在入射离子的坐标系中 ,离子感受到一种振动场的作用 .如果与此振动频率相关的能量与离子的电子态跃迁能量相匹配 ,则离子有可能被激发 ,这种现象就称为共振相干激发 (RCE) .1998年 ,成功地观测到了类氢Ar17+ 离子以相对论速度穿过Si晶体时 ,其 1s电子到n =2态的共振激发 .此后 ,有关出射离子电荷态分布以及退激X射线谱的实验研究取得了很大进展 ,近期的实验研究还观测到了类氢离子的 1s电子到更高电子态 (n =3,4 ,5 )的RCE和更重离子的RCE ,以及类氦离子的RCE .这些实验结果有助于详细研究这种共振现象 .实验结果表明 ,RCE也能够作为研究高精度原子谱学的一种潜在的工具 . When energetic ions penetrate into a crystal in a channeling condition, they travel across a periodic array of the atomic strings or ordered planes. These ions feel an oscillating field in the projectile frame. If the energy corresponding to this frequency matches with the transition energy of the electronic states of the ions, the ions have a chance to be excited. It is called Resonant Coherent Excitation (RCE). We have succeeded in observing resonant excitation of 1s electron to the n=2 states in H-like...
分子和金表面相互作用的第一性原理研究
李红海, 李英德, 王彦华, 王传奎
2002, 19(2): 218-220. doi: 10.11804/NuclPhysRev.19.02.218
摘要:
从第一性原理出发利用密度泛函理论研究了 4 ,4′ 二巯基联苯分子和金表面的相互作用 ,并利用了前线轨道理论和微扰理论定量地确定了该相互作用能常数. By using density functional theory, we have investigated the interaction between a thiol-phenyl molecule (4-4′-dimercaptodibenzene) and a gold surface. The frontier orbit theory and the perturbation theory are also employed to determine quantitatively the constant of interaction energy. The results show that the bonding between the sulfur atom and the gold atoms corresponds mainly to the covalent bond and some molecular orbits are extended over the molecule and gold cluster which certainly give channels...
H9团簇的电子结构与能量计算
孙悦, 清泉, 杨向东
2002, 19(2): 221-223. doi: 10.11804/NuclPhysRev.19.02.221
摘要:
对氢原子团簇H9的电子结构提出了一个物理模型 .认为其电子结构类似于氟原子的电子结构 ,具有 2个 1s电子 ,2个 2s电子和 5个 2p电子 .其基态可写为H9(1s2 2s2 2p5) 2 P .用电子波函数计算出该团簇的总能量为E =- 4 .99(Har.atomicunit) ,键长为R =1.5 9a0 ,与过去用改进的量子力学排列通道法计算的结果非常吻合 .这表明所提出的物理模型是合理的 ,而且所提出的电子波函数对研究H9团簇的物理性质很有用. The electronic structure of H 9 cluster is proposed. The total energy of this cluster is calculated by using its electron wave functions. The results are in good agreement with the value calculated by using of the modified arrangement channel quantum mechanics method in a previous paper. The results also indicate that the electronic structure of H 9 cluster is similar to that of fluorine atom.
铋纳米管电子性质的第一原理研究
苏长荣, 李家明
2002, 19(2): 224-226. doi: 10.11804/NuclPhysRev.19.02.224
摘要:
运用第一原理分子动力学方法系统研究了铋纳米管的稳定性和电子性质 .发现铋纳米管的应变能 (StrainEnergy)符合经典的 1/R2 规律 .铋纳米管的能隙在 0 .7— 0 .8eV左右 ,具有半导体的特性. A first principle molecular dynamics with density functional theory and ultra-soft pseudopotential has been performed on the bismuth nanotubes. The strain energies are found to follow the classical 1/R 2 strain law. The bismuth nanotubes are expected as semi-conductor with the band gaps around 0.7 - 0.8 eV.
丙酮分子团簇结构的量子化学从头计算研究
许雪松, 胡湛, 金明星, 刘航, 丁大军
2002, 19(2): 227-230. doi: 10.11804/NuclPhysRev.19.02.227
摘要:
采用HF/ 3 2 1G 方法对丙酮分子团簇体系 (CH3 COCH3 ) n(n =2— 5 )进行了全优化 .用密度泛函B3LYP/ 6 31+G 方法计算了各个体系的总能量 .通过计算不同体系的振动频率 ,确定得到的结构是否对应于体系的稳定构型 .对计算结果进行了分析和讨论 ,结果表明 ,环形结构较线形结构更为稳定 . The acetone clusters are studied by ab initio calculations. HF/3-21G * method is used to optimize the configurations for all kinds of systems. B3LYP/6-31+G ** method is adopted to calculate the total energy of the systems. We also calculate the vibration frequencies in order to investigate whether the system correspondes to stable geometries. All results show that ring structure is more stable than linear structure for the acetone clusters of (CH 3COCH 3) n(n=2, 3, 4, 5).
团簇离子在固体中能损的非线性效应
杨朝文, 缪竞威, 杨百方, 师勉恭, 刘晓东
2002, 19(2): 231-233. doi: 10.11804/NuclPhysRev.19.02.231
摘要:
研究了每核子能量为 2 6 0— 4 5 0keV的H+2,H+3,H+4 H+5和H+7团簇离子在金膜中的能损 .发现团簇离子中平均每个质子的能损大于相同速度的单质子能损 ,即能损比大于 1,且随团簇离子的大小和速度的增加而增加. The energy losses of cluster ions H+2,H+3,H+4 H+5 and H+7with energy of 260-450 keV/p in solid films have been measured. It has been found that the energy loss per proton in clusters is larger than that of single proton with the same velocity as clusters, that is, the energy ratio is larger than 1. Energy ratio increases with increasing the cluster size and velocity.
H3+团簇离子的实验研究
杨百方, 缪竞威, 杨朝文, 师勉恭, 刘晓东
2002, 19(2): 234-237. doi: 10.11804/NuclPhysRev.19.02.234
摘要:
报道了H+ 3 离子通过碳膜后 ,在其中产生的各种微量产物的测量结果 ,讨论了离子与碳膜作用中的电荷交换过程 ,分析了这些微量产物的形成机理 ,证明在产物的形成中电荷交换过程起关键作用 ,研究了离子与碳膜作用中的团簇效应和尾流效应. The yields of H -, H, H 2, H + 2 and H + 3 for H + 3 ions passing through carbon foils have been measured respectively.The results show that the charge exchange process in the interaction of Hydrogen ions with carbon foils plays a key role in the formation of these products. The cluster effects and wake effect of H + 2 and H + 3 ions in carbon foils are also discussed.
自由钨团簇与氮分子反应性的尺寸相关性
金明星, 丁大军, Mats Andersson, ArneRosén
2002, 19(2): 238-241. doi: 10.11804/NuclPhysRev.19.02.238
摘要:
用激光蒸发团簇源产生Wn团簇束 ,团簇通过一个充有N2 气体分子的低压反应池 ,利用飞行时间质谱探测反应产物 ,在单次碰撞条件下研究了W+ 10 —W+ 50 和N2 分子的反应性 ,在室温条件下测量了N2 分子与W+ n 团簇反应的反应几率 .n =10— 2 6的团簇与N2 分子的反应几率与团簇尺寸有很强的相关性 ,n =16 ,2 2 ,2 3的团簇有较高的反应性 .W+ n 与N2 分子的反应性与Wn与N2 分子的反应性显示出相似的规律性. A beam of tungsten clusters, seeded in He gas, is produced in a pulsed laser vaporization source. We have studied the size-dependent reactivity of positive tungsten cluster ions with N 2 under single-collision conditions by using laser-vaporization source, low-pressure reaction cell and time-of-flight mass spectrometer. The reaction probability with N 2 molecule was measured as a function of cluster size, W + 10-W + 50, for clusters produced at room temperature...
激光辅助的电子对氢原子的自由-自由跃迁
李书民, 陈激, 周子舫, 张声涛
2002, 19(2): 242-244. doi: 10.11804/NuclPhysRev.19.02.242
摘要:
在一级玻恩近似和软光子近似下 ,研究了激光场中电子对氢原子基态的自由 自由跃迁,并考虑入射电子对束缚电子的交换效应 .发现Kroll Watson截面求和规则在大角度遭到明显破坏. In the first Born approximation and the soft-photon approximation, the laser-assisted electron-atomic-hydrogen free-free transition is investigated with taking the exchange effect into acount. We find that the Kroll-Watson sum rule is significantly violated in the backward direction.
高强度磁场中氢原子性态的研究
胡先权, 胡文江, 林传
2002, 19(2): 245-249. doi: 10.11804/NuclPhysRev.19.02.245
摘要:
采用变分法和微扰法相结合的方法 ,把高强度磁场中氢原子的哈密顿H分为三部分 :球对称哈密顿 ;z分量角动量算符相应部分和非球对称势微扰 ,并用一种特别规定的分解法将哈密顿H中含磁场平方项的势能分解为球对称与非球对称两部分 ,且使非球对称部分引起的一级修正能量值为零 ,并采用一种简便的变分法直接求出B2 对能级的二级修正值 .这一方法不仅计算简单 ,而且提高了计算结果的精度 .计算了在均匀高强度静磁场下氢原子的 11个低能态能级和平均半径 ,讨论了高强度磁场对能级和半径的影响. In this paper we separate the Hamiltonian into three parts: a spherical symmetry Hamiltonian; a z-component of the angular momentum operator, and a non-spherical symmetric potential as the perturbation operator, and provide a propose method by separating the potential containing squared magnetic field B 2 into two parts: spherical symmetric and non-spherical symmetric ones so that the first-order energy correction due to the non-spherical symmetric potential is zero...
阶梯型三能级原子-腔耦合系统中Fock态的产生
龚尚庆, 冯勋立, 徐至展
2002, 19(2): 250-252. doi: 10.11804/NuclPhysRev.19.02.250
摘要:
探讨了阶梯形三能级原子 腔耦合系统中由绝热跟随技术引起的光子Fock态的产生 .结果发现 :对于单模腔QED系统 ,通过受激拉曼绝热跟随技术 ,在微波区域内可实现单光子Fock态的制备 ;对于双模腔QED系统 ,通过斯塔克移动的快绝热跟随技术可实现双光子对Fock态的产生.The behavior of an atom-cavity system using a three-level ladder atom was investigated. It is found that, for one-mode cavity QED, a single photon can be generated via the technique of stimulated Raman adiabatic passage; for two-mode cavity QED, a two-photon pair can be generated via Stark-shift rapid adiabatic passage.
囚禁于巴基球内的原子的里德堡特性
张现周, 焦照勇, 饶建国
2002, 19(2): 253-256. doi: 10.11804/NuclPhysRev.19.02.253
摘要:
通过非线性变换和特殊设计结点的B样条函数研究计算了囚禁于巴基球内的氢原子里德堡能级结构和振子强度 .结果表明 ,巴基球等效势阱深度可以有选择的影响和改变里德堡原子的特性 ;囚禁原子拥有很多自由原子所没有的奇特性质. Rydberg energy levels and oscillator strength of endohedrally confined H atom have been calculated by using a nonlinear algebraic mapping technique and B-spline method.The boundary conditions are conveniently satisfied with a specially designing knot sequence.Our results show that endohedral can selectively alter the properties and energy levels of Rydberg atoms, and such atoms possess some properties and behaviours which are not previously met or studied in free systems.
用谱拟合法计算强激光场中氢原子的高次谐波谱
乔豪学, 李白文
2002, 19(2): 257-260. doi: 10.11804/NuclPhysRev.19.02.257
摘要:
介绍了一种新的求解含时薛定谔方程的谱拟合法 .该方法把含时波函数在少量且分布稀疏的网格点上拟合 ,结合泰勒级数展开 ,用相对简单的计算得到包括Δt高次项贡献的含时波函数 .并将这一方法用于强激光场中氢原子高次谐波谱的计算 ,得到了与其它方法一致的结果. A new spectral fitting method for solving the time-dependent Schrdinger equation has been developed and applied to the atom in intense laser fields. By using this method, the time-dependent wave functions are determined with few and far between discrete mesh points. And the high accuracy wave functions with contribution of high-order-term of Δt are obtained by using Taylor series expand method. Our method is proved by computing high order harmonic generation spectra of hydrogen in laser fields...
DTA模型计算高温Mg等离子体的辐射不透明度
靳奉涛, 曾交龙, 袁建民
2002, 19(2): 261-264. doi: 10.11804/NuclPhysRev.19.02.261
摘要:
使用DTA(detailedtermaccounting)模型计算了温度为 5 6eV、密度为 0 .0 1g/cm3 的Mg等离子体的辐射不透明度以及Rosseland和Planck平均不透明度 .对于处于局域热动平衡 (LTE)下的Mg等离子体 ,利用Saha方程计算出各价离子的丰度 .MCHF方法得到Mg各价离子的能级以及束缚 束缚跃迁的振子强度 ,考虑了Doppler展宽和碰撞展宽 ,谱线线型采用Voigt线型 .束缚 自由以及自由 自由吸收截面使用AA模型得到. The spectral resolved opacity of high temperature Mg plasma at a temperature of 56 eV and a density of 0.01 g/cm 3 is calculated by the detailed term accounting (DTA) model. Saha equation is applied to obtain the population distribution of the plasma in local thermodynamic equilibrium. Atom levels and bound-bound absorption oscillator strengths are obtained from a multi-configuration Hartree-Fock (MCHF) calculation that includes Breit-Pauli relativistic correction. After ...
稠密氘和氢氘混合等离子体辐射不透明度的研究
陈其峰, 蔡灵仓
2002, 19(2): 265-268. doi: 10.11804/NuclPhysRev.19.02.265
摘要:
用强平面激波对氘和氢氘等摩尔混合气体进行冲击压缩 ,产生密度约为 3.7× 10 - 3 — 7.0×10 - 3 g/cm3 等离子体.由记录的等离子体发光过程的上升前沿 ,确定了氘和氢氘等离子体光谱吸收系数随光学波长变化. Plasma is generated by passage of strong planar shock wave through gas. Initial experiments in deuterium and equal mol mixture of hydrogen and deuterium have been performed to produce plasma with 3.7×10 -3-7.0×10 -3 g/cm 3density. The variation of the opacity of the plasma with wavelength is measured by recording the risetime of the emitted light.
关于分子磁性理论的研究
邝小渝, 周康巍, 清泉
2002, 19(2): 269-274. doi: 10.11804/NuclPhysRev.19.02.269
摘要:
已建立的一种研究过渡族元素化合物分子磁性的DSF理论方法 ,在一定范围内解决了分子磁性理论研究中如何将物理模型付诸理论计算的问题 ,由此研究了一些弱共价的同核分子体系 ,首次揭示了这些分子的铁磁性是起源于分子内相邻过渡金属离子轨道间的交叉相互作用 ,反铁磁性则源于平行相互作用 .通过发展GJK模型 ,又建立了能描述异核分子和共价分子的磁性理论 ,并由此分析和解释了多种无机、有机化合物和生物蛋白分子中的磁性起源 ;特别是对核糖核酸还原酶中的强共价体系的强反铁磁现象给出了合理的理论解释. Recently, we have established a DSF theoretical method suitable for researching molecular magnetism of the compounds consisting of transition group elements. By this method, we have revealed that the ferromagnetism of molecules is due to the cross-interaction between d orbitals of adjacent transition-metal ions, and that the antiferromagnetism is due to the parallel interactions. Further more, we have also established a magnetism theory for heterodinuclear...
Brǖschweiler量子搜索算法的改进及其实验实现
杨晓冬, 魏达秀, 罗军, 缪希茄
2002, 19(2): 275-277. doi: 10.11804/NuclPhysRev.19.02.275
摘要:
量子计算与经典计算相比 ,能够极大地提高运算速度 ,解决一些经典计算不能解决或很难解决的问题 .对于在无序数据库中进行搜索这类问题 ,可以用量子算法 ,如Br櫣schweiler量子搜索算法来解决 .与经典算法相比 ,Br櫣schweiler量子算法能够指数次地提高搜索速度 .在Br櫣schweiler提出的算法中 ,数据量子位和观测量子位 (辅助量子位 )是分开的 ,属于不同的量子位 .通过研究 ,对Br櫣schweiler算法作了改进 ,使之不需要用辅助量子位 ,就可以达到指数次提高搜索速度的目的 .改进后的Br櫣schweiler量子算法有利于简化实验的设计和实现过程 .同时还利用核磁共振实验 ,演示了改进后的Br櫣schweiler量子算法的实现. In recent years, quantum computing research has made big progress, which exploit quantum mechanical laws, such as interference, superposition and parallelism, to perform computing tasks. The most inducing thing is that the quantum computing can provide large rise to the speedup in quantum algorithm. Quantum computing can solve some problems, which are impossible or difficult for the classical computing. The problem of searching for a specific item in an unsorted database can be...
七量子位Deutsch-Josza量子算法的核磁共振实验实现
魏达秀, 杨晓冬, 罗军, 孙献平, 曾锡之, 刘买利, 丁尚武
2002, 19(2): 278-280. doi: 10.11804/NuclPhysRev.19.02.278
摘要:
近年来 ,量子计算机的研究有了很大的发展 ,在目前提出的各种量子计算的方案中 ,核磁共振技术对模拟和演示量子算法以及验证量子计算机的优越性做出了巨大的贡献 .Deutsch Jozsa算法是一种研究较为广泛的量子算法 ,它可以用核磁共振实验予以验证 ,并可根据Cirac等人提出的方案予以简化 .报道了在核磁共振量子计算机上实验实现七位Deutsch Jozsa算法的过程和结果. Recent years, remarkable progresses in experimental realization of quantum information have been made, especially based on nuclear magnetic resonance (NMR) theory. In all quantum algorithms, Deutsch-Jozsa algorithm has been widely studied. It can be realized on NMR quantum computer and also can be simplified by using the Cirac s scheme. In this paper, at first the principle of Deutsch-Jozsa quantum algorithm is analyzed, then we implement the seven-qubit Deutsch-Jozsa algorithm...
HIRFL-CSR实验环内靶系统
蔡晓红, 卢荣春, 曹柱荣, 杨威, 马新文, 詹文龙, D.K.Torpokov, D.Nikolenko
2002, 19(2): 281-284. doi: 10.11804/NuclPhysRev.19.02.281
摘要:
兰州重离子加速器冷却储存环 (HIRFL CSR)的内靶系统 ,是用于为实验环内的物理实验提供厚度为 10 11— 10 13 atoms/cm2 的团簇靶和极化靶 .采用超声喷气技术获得团簇粒子束 ,采用Stern Gerlach方法获得极化氢束和极化氘束. The structure and the design of the HIRFL-CSR internal target system is reported. The HIRFL-CSR internal target can operate in two modes: cluster target mode and polarized target mode. The cluster target may provide the gas target of H 2, N 2, noble gases and small molecular gases with a density of ≥10 13 atoms/cm 2, and the polarized target may provide polarized H and D beams with a density of about 2×10 11 atoms/cm 2. The target polarization is expected to be...
不稳定锂同位素移位的高精度测量实验方案(英文)
王海鸣, A.Dax, G.Ewald, I.Katayama, R.Kirchner, W.Nrtersh user, H.-J.Kluge, T.Kǖhl, R.Sanchez, I.Tanihata, M.Tomaselli, C.Zimmermann
2002, 19(2): 285-289. doi: 10.11804/NuclPhysRev.19.02.285
摘要:
对丰中子晕核11Li的核电荷均方根半径的实验确定 ,特别是其与9Li的半径的差值 ,将对各种核模型进行灵敏的检验 .选择锂的合适跃迁 ,利用激光光谱技术高精度测量该跃迁的同位素移位 ,并扣除精确理论计算的质量移位贡献值 ,可以用来确定有关同位素的核电荷均方根半径 .就目前能够提供的实验设备和手段 ,对于不稳定锂的同位素8,9Li和短寿命丰中子晕核11Li而言 ,这是能够得到与核模型相独立的电荷半径值的唯一可行的方法 .这类实验正在德国重离子研究中心 (GSI)和欧洲核子中心的ISOLDE/CERN上计划实施 .描述了锂原子的激光激发共振电离途径和进行锂的同位素移位测量的实验装置,并讨论了采用这种方法测量到的6,7Li的初步结果及其精度 ,以及使用该方法研究不稳定核的灵敏性. A high-resolution isotope shift measurement of lithium isotopes in a suitable transition, combined with an accurate theoretical evaluation of the mass-shift contribution in the corresponding transition, can be used to determine the root-mean-square nuclear charge radii of these isotopes. For the unstable 8,9Li and the short-lived halo nucleus 11Li, this is the only approach available for obtaining nuclear-model-independent values of the charge radii within the reach of present-day facilities...
ZnS∶Mn2+与ZnS∶Fe3+体系的基态零场分裂理论研究
迭东, 邝小渝, 鲁伟
2002, 19(2): 290-294. doi: 10.11804/NuclPhysRev.19.02.290
摘要:
在ZnS晶体中掺入Mn2 + 或Fe3 + 离子的EPR谱已得到了广泛的研究 .然而 ,理论结果显示其EPR零场分裂的计算值远小于实验观察值 ,这一理论与实验的矛盾至今仍未得到满意的解决 .假定在四面体ZnS中 ,S原子在成键时采取了sp3 杂化轨道的形式 ,从而使S离子显示出正的有效电荷 .从这一观点出发 ,通过对角化三角场中的微扰能量矩阵 ,使得ZnS∶Mn2 + 和ZnS∶Fe3 + 体系的EPR零场分裂参量α ,D和 (a -F)的实验值都能得到满意的解释. The EPR spectra of Mn 2+ and Fe 3+ ions in ZnS∶Mn 2+ and ZnS∶Fe 3+ systems have been extensively studied. However, the theoretical results show that the calculation values of the zero-field splitting are always much less than those of the experimental findings. Up to now, this difficulty has not yet been satisfactorily removed. In present paper, we assume that the sulfur ion has a sp 3 hybrid configuration in tetrahedral ZnS, so that the sulfur ion displays a positive...
强场方程解的边界完备性与高次谐波平台
杨玉军, 朱颀人
2002, 19(2): 295-297. doi: 10.11804/NuclPhysRev.19.02.295
摘要:
使用二阶对称分拆光谱方法和一维短程势原子模型对强光辐照下原子的高次谐波谱进行了重新计算 ,第一次实现了强场方程解的边界完备性 ,从而获得了更为清晰的谐波谱和展宽的谐波平台.An exact solution of the intense-field Schr dinger equation is obtained by using the 1D short-range potential model and symmetrically splitting time-evolution operator spectral method. This solution is the first one defined in the full space without any pre-assumed boundary condition. A novel high-order harmonic spectrum is computed based on our wavefunctions. It is found that this spectrum displays clearer harmonic peaks and a wider plateau than that predicted by I p+3.2U p.
He原子价壳层跃迁的电子碰撞研究
刘小井, 朱林繁, 苑震生, 李文斌, 成华东, 徐克尊
2002, 19(2): 298-300. doi: 10.11804/NuclPhysRev.19.02.298
摘要:
在入射电子能量 2 5 0 0eV下测量了He的 11S→ 2 1S ,2 1P ,31S和 31P的微分散射截面和广义振子强度 ,并与前人的实验和理论结果进行了比较 ,认为在此入射电子能量下一阶Born近似对此 4个跃迁成立. With electron impact energy of 2 500 eV and energy resolution of 85 meV, the differential cross sections and the generalized oscillator strengths of the excitations of 1 1S→2 1S, 2 1P, 3 1S and 3 1P of helium has been measured by electron energy loss spectroscopy . Comparing with previous experimental and theoretical results, it seems that the first Born approximation is valid for these excitations under such an electron impact energy.