Radiative lifetimes of excited W II levels

Radiative lifetimes of 19 selected W II levels with energies between 36 000 cm^-1 and 55 000 cm^-1 have been measured with the time-resolved laser-induced fluorescence technique. The ions are generated in a hollow cathode discharge and stored in a linear Paul trap. Selected states are populated with tunable dye laser pulses and the subsequent fluorescence is measured by means of a 5 Gigasample transient digitizer and a fast photodetector with a risetime of 700 ps. By taking into account both the temporal profile of the laser pulses and the separately measured response function of the system, the lifetime can be determined from the full decay curve. A refined evaluation procedure, taking into account saturation effects in the signals, reduces the uncertainty in our data to around 1%. Received: 30 July 1998 / Revised: 18 August 1998     

类镍铱离子光谱跃迁研究

重元素高电离的离子特性对研究激光核聚变和Ｘ射线激光等都很重要，本文用３ｄ＾９４ｓ，３ｄ＾９４ｄ，３ｄ＾９４ｐ，３ｄ＾９４ｆ组态相互作用研究了类镍铱离子光谱跃迁。     

Scaled DFT Force Constants and Vibrational Spectrum of Cyclopropylamine

Abstract

The molecular structure and harmonic vibrational frequencies of cyclopropylamine have been calculated using the B3LYP density functional method with the 6‐31G(2d,2p) basis set. The scaled DFT force field gives very good reproduction of the experimental vibrational frequencies. Several of the vibrational fundamental modes assigned previously are reassigned on the basis of the B3LYP/6‐31G(2d,2p) method and the scaled force field calculations. The optimized scaling factors were used to scale the B3LYP/6‐31G(2d,2p) force field of cyclopropane and cyclopropylamine (–ND₂) molecules.     

高压下铜的声子谱和弹性系数

 以Foiles、Baskes和Daw提出的嵌入原子势（EAM）为基础,并结合Vinet-Rose形式的普适物态方程,建立了金属铜原子间的EAM势。在此基础上,用EAM势和第一原理微扰理论方法计算了高压下铜的声子谱和弹性系数。通过适当地调整嵌入原子势参数,这两种方法几乎能够给出完全一致的结果。而且,晶格振动声子谱和比热的理论值与实验值符合得也非常好。     

离子交换纤维的红外光谱研究

合成了离子交换纤维交研究了它们的红外光谱，得到了一些有价值的结果。     

非对称离子门控制方法和对离子迁移谱分辨率的改善

为了改进离子门的驱动方式,简化离子门驱动电源设计和提高离子迁移谱分辨率,通过增加一组电阻实现离子门两端的不对称供电,再对低电压端的电压进行控制实现离子门功能。分析了该方式下的两种情况对迁移管内的电场、离子迁移谱的分辨率和信噪比的影响。借助SIMION7.0对离子门两边的电场分布进行了模拟和比较,并应用数值化拉普拉斯方程的方法计算了迁移管轴线的电场数据。实验证明：相比常规迁移谱的离子门浮地驱动电源,这种驱动方法成本低,离子门电源的设计简单,能够明显提高离子迁移谱的分辨率。该方法能够应用于离子迁移谱的测量仪器或实验设备。     

The Fundamental Infrared Spectrum of the Ammonium Ion in Aqueous Solutions

The infrared absorptions of NH₄ ⁺ of aqueous solutions of NH₄ ⁺ salt solutions were recently considered in some detail and, based on changes in the contour of the water band, the effect of anions of the water absorption were discussed.¹ We find, however, that differences of the contours of absorptions of pure water and of aqueous solutions can easily produce an artifact.     

Quadrupole Transitions in the Bound Rotational-Vibrational Spectrum of the Hydrogen Molecular Ion

The three-body Schrödinger equation of the ${{\rm H}_{2}^{+}}$ hydrogen molecular ion is solved in perimetric coordinates using the Lagrange-mesh method. Energies and wave functions of the four lowest vibrational bound or quasibound states for total orbital momenta from 0 to 40 are calculated with high accuracy. A simple calculation using the associated Gauss quadrature provides accurate quadrupole transition probabilities per time unit between those states over the whole rotational bands.     

Microwave Spectrum,Nuclear Quadrupole Coupling Constants,and Structure of Bromodifluoromethane

The microwave spectrum of bromodifluoromethane, CHBrF₂(Halon 1201) has been studied for the first time from 7 to 40 GHz. A least-squares analysis of the observedc-type transition frequencies gave rotational and centrifugal distortion constants and components of the bromine nuclear quadrupole coupling constant tensor in the principal axes system as follows:A= 10199.7186(62) MHz,B= 2903.4150(26) MHz,C= 2360.1521(23) MHz, Δ_J= 0.660(14) kHz, Δ_JK= 2.87(11) kHz, Δ_K= 8.95 kHz, δ_J= 0.1344(24) kHz, δ_K= 3.22(15) kHz, χ_aa= 521.281(92) MHz, χ_bb− χ_cc= −38.32(9) MHz, and |χ_ac| = 187.1(26) MHz for the⁷⁹Br species;A= 10199.5567(54) MHz,B= 2876.5588(20) MHz,C= 2342.3796(18) MHz, Δ_J= 0.652(12) kHz, Δ_JK= 2.77(9) kHz, Δ_K= 8.21(61) kHz, δ_J= 0.1300(19) kHz, δ_K= 2.97(13) kHz, χ_aa= 435.61(10) MHz, χ_bb− χ_cc= −32.08(8) MHz, and |χ_ac| = 148.5(29) MHz for the⁸¹Br species. The structural parameters are calculated from all these rotational constants and the electronic properties of the carbon–bromine bond in bromodifluoromethane are evaluated from the observed nuclear quadrupole coupling constants. These molecular properties are compared with those of other related molecules.     

用电离光谱技术测量钾分子激发态的振动常数

用染料激光激发钾蒸气，观察到了与钾分子电子态5^3Hu振动能级相关的电离谱，根据电离谱峰对应的激光波长值计算出了钾分子5^3Hu态的振动结构常数，在实验误差范围内与Magnier和Millie的理论计算结果一致。     

离子束溅射沉积不同厚度铜膜的光学常数研究

利用Lambda-900分光光度计对离子束溅射沉积不同厚度Cu膜测定的反射率和透射率,运用哈德雷方程,并考虑基片后表面的影响,对离子束溅射沉积的Cu膜光学常数进行了计算。结果表明,在同一波长情况下,膜厚小于100 nm的纳米Cu膜光学常数随膜厚变化明显;膜厚大于100 nm后,Cu膜的光学常数趋于一定值。Cu膜不连续时的光学常数与连续膜时的光学常数随波长变化规律不同;不同厚度的连续膜的光学常数随波长变化规律相同,但大小随膜厚变化而变化。     

用光学透射谱分析薄膜光学参量的一种简易方法

基于经典的色散理论建立的单振子光谱分析模型,通过理论推导,借助计算机辅助处理,提出了一种比较简捷直观的只利用垂直透射光谱对薄膜光谱进行分析的方法.利用这种方法分析了直流溅射制备的ZnO薄膜的透射光谱,计算出了薄膜在透明振荡区的折射率色散关系以及厚度等参量,并对分析方法给出了验证.     

The Microwave Spectrum and Quadrupole Coupling Constants of cis-2-Chlorophenol

The rotational spectrum of cis-2-chlorophenol was observed from 5 to 12 GHz by molecular beam Fourier transform microwave spectrometer (MB-FTMW). The rotational and quadrupole coupling constants for the ³⁵Cl of the molecule were determined: A=2985.4479(22) MHz, B=1549.8591(3) MHz, C=1020.1915(1) MHz, χ_aa=−68.2429(83) MHz, χ₋=−0.922(20) MHz, χ_ab=−11.4(19) MHz. The quadrupole coupling constants of the chlorine nuclei of cis-2-chlorophenol were nearly equal to that of the chlorobenzenes. We concluded that the electric field gradient of the chlorine atom in cis-2-chlorophenol is similar to that of other chlorobenzenes, although the suggestion of intramolecular hydrogen bonding.     

低能氮离子注入固态羧酸钠的光谱分析

对２５ｋｅＶ Ｎ＾＋离子束辐照羧酸钠引起其分子结构的变化进行了研究,通过紫外光谱的分析,得到了离子注入后苯甲酸钠的残存剂量效应曲线,辐照后乙酸钠样品产生了新的具有紫外吸收的物质。傅里叶红外光谱分析证明,两种羧酸钠样品辐照后的产物中含有新的化学基团氰基。     

透明光学树脂中Eu3+辐射参数的理论和实验研究

报道了一种新合成的含三元稀土配合物的透明光学树脂材料的辐射特性的研究。基于J-O参数理论,利用含稀土配合物Eu(TTA)3phen-0.31wt%的光学树脂的发射荧光光谱,计算了Eu3 在光学树脂基质中的J-O参数Ω2=10.139 4×10-20cm2,Ω4=3.810 9×10-20cm2,Ω6=9.050 7×10-20cm2。利用得到的J-O参数可以计算光学树脂中Eu3 的跃迁振子强度fcal,5D0激发态的辐射跃迁概率A(456.6 s-1)、辐射寿命τ(2 190.1μs),还计算了光学树脂中Eu3 的跃迁5D0→7FJ′(其中J′=1,2,4,6)的发射截面σ、荧光分支比β。通过分析计算得到的J-O参数可知,光学树脂中Eu3 的5D0亚稳态的寿命较长,跃迁5D0→7F2的发射截面最大,说明含稀土配合物的光学树脂具有作光放大或激光材料的潜在性。     

Calculation of the Interelectronic-Interaction Correction to Radiative Recombination of an Electron with a Heavy He-Like Ion

We present a calculation of the interelectronic-interaction correction of first order in 1/Z for radiative recombination of an electron with a heavy He-like ion in the ground state. A rigorous relativistic treatment is demonstrated which includes the Coulomb, Breit and retarded parts of the interelectronic interaction. A complete relativistic evaluation is compared with two frequently used approximations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Study of Radiative Deexcitation Processes in the Muonic Helium(4) Ion at 14 and 40 Atmospheres

To search for a long living 2S_1/2 state in the muonic helium ion at helium gas pressures of 14 and 40 atmospheres, radiative muon transitions were registered in a time resolved mode using sodium iodide crystals. Special care was taken to avoid gas impurities which are known to reduce the 2s lifetime significantly. In addition to the prompt photons of the K-series, a delayed component was detected. The lifetime and yield of this component agree with theoretical values for ions not perturbed by the surrounding medium. However, test measurements carried out with other target gases clearly demonstrate that practically all of the delayed events observed in pure helium are not caused by the radiative decay of a longliving 2s state.     

Radiative corrections to sin2 θ W exp in theS U(5) model

Zeitschrift für Physik C Particles and Fields - We compute perturbatively in theSU(5) grand unification theory the radiative corrections to sin2 θ W O through a phenomenological weak...