Measurement of the nuclear magnetic dipole moments of 177Hf and 179Hf with the atomic beam magnetic resonance method

The nuclear ground-state magnetic dipole moments of ¹⁷⁷Hf and ¹⁷⁹Hf have been determined with the atomic beam magnetic resonance method. The results are: $\text{μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{177}\text{Hf}\text{= 0.7836(6)μ}{}_{\mathrm{<mtext>N</mtext>}}\text{, μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{179}\text{Hf) = ?0.6329(13) μ}{}_{\mathrm{<mtext>N</mtext>}}$ (uncorrected for diamagnetic shielding).     

Hg~+离子5d~(10)6s ~2S_(1/2)→5d~96s~2 ~2D_(5/2)钟跃迁同位素位移和超精细结构的理论研究

本文首先在Dirac-Hartree-Fock近似下理论评估了Hg~+离子5d~(10)6s ~2S_(1/2)→5d~96s~2 ~2D_(5/2)钟跃迁的质量位移(mass shift, MS)和场位移(field shift, FS)在其同位素位移(isotope shift, IS)中的相对贡献,发现MS远小于FS而可以被忽略.在此基础上,通过系统地考虑该原子体系中主要的电子关联效应,计算了这条钟跃迁FS的精确值以及涉及到的上下两个能级的超精细结构常数,并得到了几种稳定汞同位素离子该跃迁的IS和超精细结构分裂.其中,计算的~(199)Hg~+和~(198)Hg~+离子之间的钟跃迁频率偏移与已有实验测量值相比误差为2%左右.最终,本文给出了汞离子7种常见同位素该谱线的绝对频率值,为实验上的谱线测量提供了有效的理论依据.     

Magneto-optical study of the 5ƒ2 → 5ƒ16d1 transition in UO2

High field Faraday rotation and magnetic circular dichroism measurements in the energy range between 1.4 and 5.4eV are reported for UO₂. The measurements are compared with two modified atomic models for the 5?² → 5?¹6d¹ transition using LS- and jj-coupling, respectively. Excellent agreement between theory and experiment is found only for a jj-coupling treatment of the final state.The Faraday rotation for magnetic saturation is estimated to be 3 × 10⁶ deg cm^?1 at 4.5 eV.     

Hyperfine structure measurements in metastable atomic states — nuclear spins of 201Pb and 203Pb

A new atomic-beam source has been used to populate metasbable states within the atomic ground-state configuration for lead. With this source and the atomic-beam magnetic resonance method, hyperfine structure measurements have been performed in metastable states to determine the nuclear ground-state spins of two lead isotopes as ${}^{203}\text{Pb}\text{(I =}\text{5}\text{2}\text{)}$, ${}^{201}\text{Pb}\text{(I =}\text{5}\text{2}\text{)}$.     

The establishment of the 5d23F and 1S levels in Ba I

The metastable 5d²³F levels in Ba I have been established by observations in the extra-photographic infrared. The 5d²¹S level has been established in connection with identifications of laser lines observed by Cahuzac and lines observed by selective excitation.     

Observation of the radiative 2s02p6−2s12p5 transition in NeIII

Ion impact excited spectra of Ne contain a line at 52.82 nm which has been identified as resulting from the decay of double 2s vacancies in NeIII via the transition 2s⁰2p⁶(¹S₀)?2s¹2p⁵(¹P₁).     

Nb XIII离子3d94s2, 3d94s4p, 3d94p2 组态能级结构与跃迁的理论研究

用准相对论Hartree-Fock方法对Nb XIII离子二电子激发组态3d⁹4s², 3d⁹4s4p, 3d⁹4p² 的能级结构做了全面系统的理论计算研究.在对已有研究结果分析的基础上, 运用最小二乘方法对径向积分参数进行了优化计算, 得到了与这些组态有关的电偶极允许跃迁的谱线波长和跃迁概率.计算结果与最新的实验值做了对比分析, 表明本文计算结果是准确的. 研究发现, 波长40.92 nm的谱线, 属于3d⁹4s(¹D)4p²F_7/2–3d⁹ (²D)4s^{2 2}D_5/2 的跃迁谱线, 而不属于3d⁹4s (¹D)4p⁴D_7/2–3d⁹(²D)4s^{2 2}D_5/2 的跃迁谱线, 即上谱项能级为²F_7/2, 而不是⁴D_7/2. 关键词： Nb XIII离子 二电子激发组态 谱线波长 跃迁概率     

Influence of relaxation effects on probabilities of the 2s2p35S2－2s22p2 3P1，2 intercombination transitions in NII

Transition probabilities of the 2s2p^3 {}^5S_2－2s^22p^2 {}^3P_{1,2} intercombination transitions in NII have been calculated by using a large-scale multiconfiguration Dirac－Fock method. In the calculation the most important effects of relativity, correlation, and relaxation are considered. From the calculated transition probabilities, the lifetime of the 2s2p^3 {}^5S_2 metastable state is derived. The result is in excellent agreement with the latest experimental result. In the meantime the influence of anomalously strong relaxation effects on probabilities of the 2s2p^3 {}^5S_2－2s^22p^2 {}^3P_{1,2} lines in NII have been found.     

The quadrupole moments of the 5− states in 116Sn, 118Sn and 120Sn

The quadrupole interaction frequencies $\text{ω}{}_0\text{=}\text{3eQ}{}_1\text{V}{}_{\mathrm{zz}}\text{41(21-1)}\text{h}\text{?}$ in the 5^? state of ¹¹⁸Sn have been measured by time differential perturbed angular correlation technique in Sn, Sb and (95% Sn+5% Sb) environments. The ω₀ for ¹¹⁶Sn was determined in Sn environment only. With the help of the known electric field gradient ¹) of Sn in a Sn lattice the quadrupole moments have been deduced as $\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{118}\text{Sn}\text{) = ±0.10(4) b}\text{and}\text{Q(5}{}^{\mathrm{?}}\text{,}{}^{116}\text{Sn}\text{) = ±0.165(60)}\text{b}$. These values together with the known²) quadrupole moment of the analogous 5^? state in ¹²⁰Sn are interpreted in terms of the pure single-particle model. The data exhibit the expected strong systematic variation of Q_I with the number of particles in the h_{$\text{11}\text{2}$}. subshell which is being filled with 1, 3 and 5 neutrons in ¹¹⁶Sn, ¹¹⁸Sn, and ¹²⁰Sn, respectively.     

Spectra and oscillator strengths of 3p63d9--3p53d10 and 3p63d9--3p63d84p transitions for cobalt-like Sn23+ ion

This paper calculates the spectra and oscillator strengths for highly ionized cobalt-like Sn23+ ions 3p63d9 3p53d10,3p63d9 3p63d84p transitions by using a multi-configuration self-consistent field method program together with the proposed fitting formula.The calculations have a good agreement with observations.     

Measurement of the quadrupole moments of the first 2+ states of 130Ba and 134Ba

The quadrupole moments of the first 2⁺ states of ^130,134Ba were measured using the reorientation precession technique. Prolate deformations were determined for both nuclei. The quadrupole moments found were Q = ?0.33 ± 0.24 b and ?0.31 ± 0.24 b for ¹³⁰Ba and ¹³⁴Ba, respectively.     

Sub-kilohertz optical linewidths of the 7F0 ↔ 5D0 transition in Y2O3:Eu3+

Homogeneous optical linewidths as small as 760 Hz (fwhm) have been observed in Y₂O₃:Eu³⁺ using delayed heterodyne photon echoes. Hyperfine and lifetime contributions to dephasing are estimated to contribute ? 300 Hz to this width, and the remainder is attributed to quasi-resonant energy transfer.     

Isospin and F-spin symmetry structure in low-lying levels of 48，50Cr isotopes

The low-energy level structure and electromagnetic transitions of ^48.50Cr nuclei have been studied using the interacting boson model with isospin (IBM-3). A sequence of isospin excitation bands with isospin T = Tz, Tz 1and Tz 2 has been assigned, and compared with available data. According to this study, the 2^3 and 2^2 states are the lowest mixed symmetry states in ^48Cr and ^50Cr, respectively. In particular, the present calculations suggest that a combination of isospin and F-spin excitation can explain the structure in these nuclei. The transition probabilities between the levels are analysed in terms of isoscalar and isovector decompositions which reveal the detailed nature of the energy levels. The results obtained are in good agreement with recent experimental data.     

Magnetic and quadrupole moments of the Zc(4020)+,Zc(4050)+,and Zc(4600)+ states in the diquark-antidiquark picture

The magnetic and quadrupole moments of the Z_c(4020)⁺,Z_c(4050)⁺,and Z_c(4600)⁺ states are calculated within the QCD light-cone sum rules.The compact diquark-antidiquark interpolating currents and the distribution amplitudes of the on-shell photon are used to extract the magnetic and quadrupole moments of these states.The magnetic moments are acquired as μ_Zc=0.50_-0.22^+0.22μ_N,μ     

11B nuclear quadrupole interaction in metal hexaborides (MB6)

The magnitude of the electric field gradient at the boron nucleus, ¦eq¦, in divalent- and trivalent-metal hexaborides (MB₆) as well as in mixed-valent SmB₆ has been measured by the nuclear magnetic resonance method. In each group of divalent- and trivalent-metal hexaborides, ¦eq¦ decreases remarkably with increasing lattice parameter. At a given lattice parameter, ¦eq¦ for the trivalent-metal hexaborides is smaller than that for the divalent-metal hexaborides. The value of ¦eq¦ for SmB₆ is situated between those for the divalent- and trivalentmetal hexaborides. On the basis of these results, the electronic structure of the hexaborides is discussed.     

Vibrational study of layered ZnPS3 compounds intercalated with [Co(η5 -C5H5)2+] and [Cr(η6 -C6H6)2+] CATIONS

Infrared and Raman spectra (10–3100 cm^?1) of the layered ZnPSs compound and of intercalates with [Co(η⁵ ? C₅H₅)₂⁺] and [Cr(η⁶ ? C₆H₆)₂⁺] cations in the polycrystalline state have been recorded 300–10 K temperature range. A complete assignment of the spectra is proposed in terms of PSs group motions, Zn²⁺ ion translations and [Co(η⁵ ? C₅H₅)₂⁺] or [Cr(η⁶ ? C₆H₆)₂⁺] internal vibrations. New low frequency for the [Co(η⁵-C₅H₅)₂⁺] intercalate at low temperature are assigned to librational and torsional modes of C₅H₅ rings. Moreover, the preresonance Raman spectra of this intercalate show a selective enhancement for the metal-ligand vibrations when the charge transfer band of the cobalticenium is approached. One concludes that guest molecules are intercalated under their cationic form, are weakly interacting with the host lattice and seem to be dynamically disordered at room temperature.     

The electric quadrupole moment of the 6+ state of 112Sn

The spectroscopic quadrupole moment of the isomeric 6⁺' (2552 keV) state of ¹¹⁷Sn has been derived from TDPAD measurements in a Cd metal host target at 500 K as $\text{Q}{}_{\mathrm{<mtext>I</mtext>}}\text{(6}{}^{\mathrm{+}}\text{,}{}^{112}\text{Sn}\text{) = ± 0.29(6)}\text{b}$. The calibration of the effective field gradient for Sn in Cd at 500 K, given by Herrlander et al. has been used. A comparison of the results with shell model estimates makes a mixed configuration of $\text{|(}\text{g}\text{7}\text{2}\text{)}{}^{\mathrm{?2}}\text{6}{}^{\mathrm{+}}\text{〉)}\text{and}\text{(}\text{g}\text{7}\text{2}{}^{\mathrm{?1}}\text{d}\text{5}\text{2}{}^{\mathrm{?1}}\text{)6}{}^{\mathrm{+}}\text{〉)}$ for the 6⁺ state most likely.     

Lifetimes of (2p53s1,3P) levels of Na II

Lifetimes of the resonance levels (2p⁵3s^1,3P) of Na II have been measured by the beam-foil method. The experimental accuracy is better than that of available theoretical predictions.     

Screening constant by unit nuclear charge calculations for (n s2)1Se, (np2)1De and (N s n p)1P○ excited states of He-like systems

Screening Constant by Unit Nuclear Charge (SCUNC) is a new analytical method suitable for the treatment of the properties of He-like systems. In this paper, the possibilities of the method are demonstrated for calculating in the framework of semi-empirical procedure, total energies, total electron-electron interaction energies and excitation energies for (ns²)¹S^e, (np²)¹D^e and (Nsnp)¹P° doubly excited states of He-like ions. The proposed semi-empirical scheme, leads to accurate results in good agreement as well as with available other theoretical results than experimental data.     

Fast beam excitation of the 1s22s2p3d2D0-term in neutral boron

After the interaction of a fast B⁺-beam with a solid surface, a carbon foil, or a gas target, a pronounced emission of light at 582.03 ± 0.02 nm is observed. We attribute this line to the $\text{2}\text{s}\text{2}\text{p}{}^2{}^2\text{P}\text{?2}\text{s}\text{2}\text{p}\text{3}\text{d}\text{'}{}^2\text{D}{}^0$ transition in doubly excited neutral boron. From our data we derive for 2s2p3d'²D term energies of $\text{E(J=}\text{3}\text{2}\text{)=89705.0 ± 0.6}\text{cm}{}^{-1}$, $\text{E(J=}\text{5}\text{2}\text{) = 89708.7 ± 0.6}\text{cm}{}^{-1}$ and a fine-structure splitting of 3.3 ± 0.2 cm^-1.