Radiative lifetimes of Zr III excited levels

We report on radiative lifetimes of 4d5p excited states of Zr III produced in a laser produced plasma. The ions were populated either in the ground state or in metastable states, and the number of ions is strongly dependent on the application of an external magnetic field, which is shown to be very important when using the time-resolved laser-induced fluorescence technique for lifetime measurements in highly charged ions. The experimental lifetime results fall in the region 1–2 ns with statistical uncertainties less than 7%. The experimental values were compared with multi-configuration Hartree-Fock calculations showing an agreement within 12–20%. The experimental values are systematically higher than the theoretical ones.     

若干Nd^3^＋和Er^3^＋配合物超灵敏跃迁光谱的研究

研究了Ｎｄ~（３＋）和Ｅｒ~（３＋）分别与邻菲罗啉、二苯甲酰甲烷、水杨酸钠组成的配合物在乙醇（或二甲基甲酰胺）－水溶液中的ｆ－ｆ超灵敏跃迁吸收光谱，用微机计算了这些跃迁的振子强度和配合物中每个配体分子引起的振子强度增大值，探讨了振子强度的变化与配位作用的关系，并根据光谱数据计算了电子云重排效应系数β、共价参数δ和键参数ｂ~（１，２），讨论了Ｌｎ－Ｌ键的性质，合成了相应的固态Ｎｄ~（３＋）配合物并测定了其吸收光谱．     

FeXIX2p~4—2p3d跃迁的进一步研究

通过对由文献[4]推出的实验能级的最小二乘拟合,得到了各优化Slater参数和弱组态相互作用参数a。用这些参数计算了各能级的理论值以及相应谱线的波长和相对强度,改正了原来归类中的个别差错。     

Relationship Between the J(Sn–C–H) of the Dimethyltin Dichloride Adducts of some Pyridines and Anilines,and the Donor Strength of the Lewis Bases

A study by titrimetric methods of the donor strength of pyridine and aniline and some of their para -substituted derivatives, and the J (¹¹⁹Sn–C–H) of their adducts with dimethyltin dichloride in nitrobenzene, has shown that the p K _b of a Lewis base and its para -substituted derivatives varies linearly with the J (¹¹⁹Sn–C–H) of the adducts of dimethyltin dichloride (Me₂SnCl₂), with the Lewis base dissolved in an inert solvent. A graphical plot of the p K _b of a given series of Lewis bases versus the J (Sn–C–H) of their complexes with Me₂SnCl₂ in nitrobenzene (at the same temperature, and same complex concentration) gives a straight line with a negative gradient, making possible the deduction of the other parameter (e.g. p K _b) for a Lewis base in the series, where the one parameter (e.g. J (Sn–C–H) is known. The graph for each series of Lewis base has its own characteristic gradient, and the gradients appear proportional in magnitude to the donor strengths of each class of the bases, making it possible to deduce from such graphs which series of Lewis bases are the stronger donors.     

Roe linearization for the Euler equations augmented by the convective terms from the k–ω turbulence model

This paper describes the method of calculation of the eigenvalues, eigenvectors of the Jacobian matrix of the Euler equations augmented by the convective part of k–ω turbulence model. The equations are 3D and values are expressed in terms of cell normals of a finite volume. The expressions for wave strengths are also found, which are also necessary to calculate the inter‐cell fluxes for Roe's scheme. Copyright © 2007 John Wiley & Sons, Ltd.     

The excitation energies,ionization potentials and oscillator strengths of neutral and ionized species of Uub (Z = 112) and the homologue elements Zn,Cd and Hg

Multi-configuration Dirac-Fock method (MCDF) is employed to calculate excitation energies, ionization potentials and oscillator strengths for all neutral and up to 5 times ionized species of element Uub, as well as the homologue elements Zn, Cd and Hg. On the basis of not too extended MCDF calculations, we studied some peculiar properties of element Uub resulting from its stronger relativistic and electron correlation effects. Using an extrapolative scheme, improved ionization potentials of Uub were obtained with an uncertainty of less than 0.5 eV. Furthermore, we calculated the low-lying resonance excitation energies, absorption oscillator strengths and the first ionization potential for Hg and Uub using large scale MCDF calculations, which improved the uncertainty of the excitation energies to less than 0.25 eV for element Hg. We hope that such calculations yield good results for element Uub.     

Two-color pump-probe experiments in helium using high-order harmonics

A pump-probe technique has been applied for measuring the lifetimes and absolute photoionization cross-sections of excited He states. The 1s2p ¹P and 1s3p ¹P states of He are excited by using the 13th and the 14th harmonic, respectively, of a tunable 70 ps dye laser generated in a Kr gas jet. The states are ionized after a varying time delay, by absorption of probe photons with energies between 1.6 and 4.5 eV. Lifetimes of τ(1s2p) = 0.57 ns and τ(1s3p) = 1.76 ns are determined with a precision of about 15%. A significant enhancement of the number of ions present in the lifetime curves at zero time delay for pressures above 6×10^-5 mbar is attributed to direct two-photon ionization of He in combination with AC Stark broadening of the excited state and absorption of the XUV light in the medium. Absolute photoionization cross-sections from the He 1s2p ¹P and He 1s3p ¹P states in the threshold region are determined by measuring the saturation of the ionization process with a precision of ∼ 25%. In addition, the variation of the relative orientation between the polarization vectors of the pump and probe beams enables the determination of partial photoionization cross-sections. Received 3 June 2002 / Received in final form 14 August 2002 Published online 22 October 2002 RID="a" ID="a"Present address: Department of Biophysics, Leiden University, 2333 CA Leiden, The Netherlands. RID="b" ID="b"Present address: Continuum Electro-Optics Inc., 3150 Central Expressway, Santa Clara, CA 95051, USA. RID="c" ID="c"Present address: CEA/DRECAM/SPAM, CEN Saclay, 91105 Gif-sur-Yvette, France. RID="d" ID="d"Present address: Department of Physics, National University of Rwanda, Butare, Rwanda. RID="e" ID="e"Present address: CELIA, Université Bordeaux 1, 33405 Talence, France. RID="f" ID="f"Present address: MAX-Lab, Lund University, Box 118, 221 00 Lund, Sweden. RID="g" ID="g"e-mail: anne.lhuillier@fysik.lth.se     

Lifetime measurements in Gd II and Gd III using time-resolved laser spectroscopy

Natural radiative lifetimes of 20 levels (energy range between 29 000-35 000 cm^-1) in Gd II and 5 levels (energy range between 43 000-49 000 cm^-1) in Gd III have been measured using time-resolved laser-induced fluorescence in a laser-produced plasma. Received 17 July 2000 and Received in final form 13 October 2000     

原子电四极矩E2光谱跃迁几率的算符形式和多电子效应研究

利用多组态Dinac-Fock广义扩展平均能级（MCDF－EAL）方法系统地计算了铍LiI3d→2s,3p→2p,碳CIII2s3d1D2→2s21so,2p21S0,钙C I功43枯1D2→4s21So,钛TiIII3d23p→323F,3d4s3D→3d23F,铜CuII 3d94s1D2→3d10 1S0,锌ZnI 4s4d1D2→4s2 1s0和铯CsI 5d→6s等电四极矩E2光谱跃迁的能级间隔,跃迁几率和振子强度,计算中考虑了重要的核的有限体积效应,Breit修正和QED修正,所得结果和最近的实验数据及其它理论计算进行了比较。     

类硼等电子序列磁偶极M1 1s22s22p2P3/2—2P1/2能级间隔和光谱跃迁

采用相对论量子力学GRASP2程序,扩展平均能级EAL模型,有限核模型,考虑Breit和QED的高阶微扰修正,系统地研究了类硼等电子序列磁偶极M1 1s22s22p2P3/2—2P1/2(Z=10～100)光谱跃迁的精细能级结构间隔,跃迁概率和振子强度,所得结果和最近的实验数据及理论计算值进行了比较。计算结果表明：在ICF高温高密度激光等离子体中磁偶极矩M1跃迁几率过程不容被忽视。