Recent hyperfine structure investigations in the configurations 4f 136s 2, 4f 136s6p,and 4f 125d6s 2 of Tm I

By use of optical hyperfine structure investigations in the Tm I spectrum theA- values of 20 levels of the configurations 4f ¹³ 6s 6p and 4f ¹² 5d 6s ² and theA-value of 4f ¹³ 6s ^{2 2} F _5/2 were determined very accurately. These data and tenA-factors from former experiments are used for theoretical calculations. 30A-factors have been interpolated from intermediate coupling wave functions using 9 effective mono-electronic parameters. The r.m.s. deviation between experimental and theoreticalA- values amounts to 0.5 10^?3 cm^?1 and represents 3/100 of the average value of the measuredA-factors.     

Laser-rf double-resonance hyperfine structure measurements of the metastable 3d 4s 1 D 2 state of43Ca

The hyperfine structure of the (3(d 4s)¹ D ₂metastable state of⁴³Ca has been measured using theABMR-LIRF method (atomic beam magnetic resonance, detected by laser induced resonance fluorescence). The measurements yielded for the magnetic dipole and electric quadrupole constantsA=?17.650(2) MHz andB=?4.642(12) MHz, respectively. From the measuredB factor the spectroscopic electric quadrupole moment (uncorrected for shielding effects) has been calculated to beQ(⁴³Ca)=?0.062(12) barn. In addition, isotope shifts in the lines (3d 4s)¹ D ₂(3d 4p)¹ F ₃ ⁰ and (3d 4s)¹ D ₂(4s 5p)¹ p ₁ ⁰ for the stable calcium isotopes have been obtained by high resolution laser spectroscopy.     

Fine structure and isotope shift of the 3s4d 3 D-3s3p 3 P, 3s5d 3 D-3s3p 3 P and 3p 2 3 P-3s3p 3 P Transitions of MgI

Summary We report the measurements of the³ D(3s4d)-³ P(3s3p)³ D(3s5d)-³ P(3s3p), and³ P(3p ²)-³ P(3s3p) transition frequency of MgI, the fine-structure separation and isotope shift between²⁴Mg and²⁶Mg. The measurements have been performed in a metastable atomic beam; a good agreement is found for data already existing in the literature. The accuracy of the measurements reported in this paper is mainly limited by the Doppler broadening of theI ₂ transitions used as a reference and by the precision in the knowledge of the related wavelengths.     

Isotope shift and hyperfine structure of the transition5d6s 2 2 D 3/2-5d6s6p 4 F 3/2 of Lu175 and Lu176

Using a tunable single mode dye laser the isotope shift of the 573.7 nm-line between the isotopes Lu¹⁷⁵ and Lu¹⁷⁶ has been determined to be IS(176?175, 573.7 nm)=?394(5) MHz yielding a change of mean square nuclear radii ofδ〈r ²〉=0.022(5) fm². In addition from our measurements the following values of the hyperfine splitting constantsA andB could be deduced Lu¹⁷⁶ 5d6s6p ⁴ F _3/2:A=?651.4(0.3) MHz,B=2,494(4) MHz 5d6s ^{2 2} D _3/2:A=138.0(0.3) MHz,B=2,131(3) MHz Lu¹⁷⁵ 5d6s6p ⁴ F _3/2:A=?924.7(0.5) MHz,B=1,767(4) MHz.     

Hyperfine structure in the 6p5d configuration and isotope shifts in transitions between the 6s5d and the 6p5d configurations in Ba I

High-resolution laser fluorescence spectroscopy, using a single-mode dye laser acting on a collimated atomic beam, has been performed to determine the hyperfine-structure (hfs) constants in six states of the 6p 5d configuration of¹³⁵Ba and¹³⁷Ba. Isotope shifts (IS) for eleven transitions between the 6s 5d and the 6p 5d configurations have also been measured. From an analysis of the energy levels, intermediate angular wavefunctions have been deduced. The wavefunctions are used to evaluate experimental hyperfine parameters from the experimental hfs constants. The parameters are, for the magnetic-dipole interaction compared with theoretical values, and for the electricquadrupole interaction used to estimate the nuclear quadrupole moments for the odd isotopes. The IS in the measured transitions are analysed using a King-plot, with the first resonance line in Ba II as the reference. Specific mass and field shifts are evaluated for the measured transitions. The field shifts have been used to determine the change in mean-square radius between the natural abundant Ba-isotopes.     

Level lifetimes in 3p and 3d configurations of Fe XII

Transitions between the five fine-structure levels in the 3s ²3p ³ ground configuration of Fe XII (P-like) are of interest in astrophysics and terrestrial plasma diagnostics. The decay rates give rise to level lifetimes in the millisecond range, which have been measured recently at a heavy-ion storage ring. While most of the 3s ²3p ²3d levels are short-lived, two of these levels have no E1 decay channels and may also have millisecond lifetimes. We present HFR and MCDF calculations of the E1, M1, E2 and M2 transition rates between the 3s ²3p ³, 3s3p⁴ and 3s ²3p ²3d levels and compare the lifetime results to most recent experimental data as well as to other predictions. Received 2 October 2001 / Received in final form 22 January 2002 Published online 28 June 2002     

Experimental transition probabilities for lines arising from the 4d5p and 4d5d configurations of ZrIII

Relative transition probabilities for 120 lines arising from the 4d5p and 4d5d configurations of ZrIII were determined from measurements of emission-line intensities in a laser-produced plasma. The experiment was carried out with Cu-Zr alloy with a Zr content lower than 13% in order to have an optically thin plasma. Transition probabilities were placed on an absolute scale by using theoretical lifetimes, line-strength sum rules and Boltzmann plot. Comparison of the present experimental results with the available theoretical data is made.     

Tensor polarizabilities and lifetimes of levels of the configurations 4f 66s6p and 4f 55d6s2 in samarium I

Stark splittings of 7 levels of the configurations 4f ⁶6s6p and 4f ⁵5d6s² in Sm I were measured by quantum beat spectroscopy in pure electric fields, allowing the determination of tensor polarizabilities. Additionally, the lifetimes of 11 levels of these configurations were determined from time-resolved registration of the exponential decay. From these values the radial integrals I(6p,6s), I(6p,5d), and I(5d,4f) were derived by a parametric analysis. Theoretical values of tensor polarizabilities and lifetimes which were calculated using these radial integrals show good agreement with experimental data of various authors.     

Tensor polarizabilities of levels of the configurations 4f 13 6s6p and 4f 12 5d6s 2 in thulium I

The level-crossing technique with parallel electric and magnetic fields was used to measure the tensor polarizabilities of six levels of the configuration 4f ¹³ 6s6p + 4f ¹² 5d6s ² in the Tm I-spectrum. Using intermediate coupling wave functions given by Camus and the experimental values of the tensor polarizabilities, the radial integrals for electric dipole transitions from levels of the configuration 4f ¹³6s6p + 4f ¹²5d6s ² to levels of the configuration 4f ¹³ 5d6s + 4f ¹² 6s ²6p have been determined. The results areI(4f ¹³6s6p,4f ¹³5d6s)=1.98(45)ea ₀ andI(4f ¹²5d6s ²,4f ¹²6s ²6p) = 0.88(25)ea ₀. A comparison between the experimental and the calculated values of the tensor polarizabilities shows an excellent agreement, provided that these radial integrals and the radial integrals for the electric dipole transitions to the ground state configuration 4f ¹³6s ² as determined by Wallenstein from lifetime measurements are used in the calculation, instead of radial integrals computed by Camus with Hartree-Fock wave functions.     

Ba原子6s5d~3 D与6p5d~3 F态的超精细结构及态间跃迁的同位素移动的直接确定

提出并演示了一种光泵预选态的原子光谱测量方法,并对Ba原子的6s5d3 D态与6p5d3 F态的超精细结构及该跃迁的同位素移动进行了直接测量。首先利用791nm的激光激发Ba原子特定同位素及特定超精细结构的6s6s 1 S0→6s6p3 P1跃迁,并利用6s6p3 P1→6s5d3 D2的自发辐射有选择地分别将这些同位素制备到6s5d3 D2态不同的超精细能级上,再用778nm的激光扫出对应的6s5d3 D2→6p5d3 F2跃迁的荧光光谱,通过这几组光谱之间的对比直接实现了对22条超精细谱线的认定和归属,从而得到了135 Ba和137 Ba的6s5d3 D2能级与6p5d3 F2能级的超精细结构常数及该跃迁的同位素移动。     

Fine- and hyperfine structure analysis of the odd configurations in the lead atom

The fine- and hyperfine structure (hfs) analysis, on the basis of available experimental data for the configuration 6s ²6p6d+6s ²6p7s+6s ²6p8s in PbI has been performed. The Slater integrals, spin-orbit parameters and the effective hfs one-electron parameters have been determined. We find an off-diagonal core-polarization effect in the 6p6d+6p7s-space. Using the calculated radial parameters, the values of the quadrupole moment for stable and radioactive Pb-nuclei have been determined from measuredB-factors of the 6p7s ³P₁ state. In addition, a repulsion effect on the hfs sublevels with the same quantum numberF has been investigated.     

Spectroscopy of the hyperfine structure of antiprotonic 4He and 3He

The spin magnetic moment $\mu^{\overline{p}}_{s}$ of the antiproton can be determined by comparing the measured transition frequencies in $\overline{p}^4$ He^?+? with three-body QED calculations. A comparison between the proton and antiproton can then be used as a test of CPT invariance. The highest measurement precision of the difference between the proton and the antiproton spin magnetic moments to date is 0.3%. A new experimental value of the spin magnetic moment of the antiproton was obtained as $\mu^{\overline{p}}_{s} = -2.7862(83)\mu_{N}$ , slightly better than the previously best measurement. This agrees with $\mu^{p}_{s}$ within 0.24%. In 2009, a new measurement with antiprotonic ³He has been started. A comparison between the theoretical calculations and experimental results would lead to a stronger test of the theory and address systematic errors therein. A measurement of this state will be the first HF measurement on $\overline{p}^3$ He^?+?. We report here on the new experimental setup and the first tests.     

Ab-initio calculations of the electronic structure of impurities and alloys of ferromagnetic transition metals

We review recent theoretical work on the electronic structure and the magnetic properties of ferromagnetic transition-metal alloys. All calculations are based on density-functional theory in the local-spin-density approximation. We report about calculations for dilute alloys using the KKR-Green's function method and for concentrated disordered alloys using the charge-self-consistent KKR-CPA method.     

Doppelresonanzuntersuchungen zum Stark-Effekt des 4s 4p 3 P 1-Terms im Ca I-Spektrum

The influence of an electric field on the Zeeman-splitting of the 4s 4p ³P₁-level was investigated using the double resonance method. From the r.f.-resonance signals the tensor polarizability of the 4s 4p ³ P ₁-level was deduced to be α_ten(³ P ₁)=3.2(8) kHz/(kV/cm)². This value is used for an estimate of the oscillator strength of the infrared transition between the multiplets 4s 4p ³ P and 4s3d ³ D. Taking into account measured oscillator strengths of electric dipole transitions from the³ P ₁-level to other low lying levels one obtainsf(4s 4p ³ P→4s 3d ³ D)=0.09.     

Dissociative multiple photoionization of Br2, IBr,and I2 in the VUV and X-ray regions: a comparative study of the inner-shell processes involving Br(3d,3p,3s) and I(4d,4p,4s,3d,3p)

Dissociative multiple photoionization of the bromine, the iodine monobromide, and the iodine molecules in the Br(3d,3p,3s) and I(4d,4p,4s,3d,3p) inner-shell regions has been studied by using time-of-flight (TOF) mass spectrometry coupled to synchrotron radiation in the ranges of 90∼978 eV for Br₂, 60∼133 eV for IBr, and 86∼998 eV for I₂. Total photoion and photoion–photoion coincidence (PIPICO) yields have been recorded as functions of the photon energy. Here, giant shape resonances have been observed beyond the thresholds of the inner-shells owing to the Br(3d¹⁰)→Br(3d⁹ϵf), I(4d¹⁰)→I(4d⁹ϵf), and I(3d¹⁰)→I(3d⁹ϵf) transitions. The dissociation processes of the multiply charged parent ions have also been evaluated from variations of photoelectron–photoion coincidence (PEPICO) and PIPICO spectra with the photon energy. From each Br(3p_3/2) (189.9 eV) and I(4p_3/2) threshold (129.9 eV), quintuple ionization of the molecules begins to play important roles in the photoionization, subsequently yielding ion pairs of X³⁺–X²⁺ (X=Br, I). From the I(3d_5/2) threshold (627.3 eV), loss of six electrons from iodine molecule additionally begins to play a minor role in the multiple photoionization, giving rise to the formation of ion pairs of either I³⁺–I³⁺ or I⁴⁺–I²⁺. A direct comparison of the strengths and the ranges of the I(4d) and Br(3d) giant resonances was successfully made from dissociative photoionization of IBr. Over the entire energy range examined, 60<E<133 eV, biased charge spread relevant to the specific core-hole states of IBr is observed, presumably reflecting the fact that charge localizes mostly in the excited atoms, which can be accounted for mainly by a two step decay via a fast dissociation followed by autoionization upon the VUV absorption.     

Supertransferred hyperfine structure in EPR of V4+ ion in Ca3In2Ge3O12 garnet

Interaction of an unpaired electron of the tetrahedral V⁴⁺ ion in Ca₃In₂Ge₃O₁₂ garnet with the four nearest In nuclei gives rise to clearly resolved structure of EPR spectra. We report the observation and analysis of these spectra at three frequencies and at temperature 77 K. The temperature dependence between liquid helium and the room temperatures was also studied. Parameters of the spin Hamiltonian are g_∥=1·8735; g_⊥=1·9825; ∣ ¦A∥|=150·4×10^?4cm^?1; ¦ A_⊥¦ = 36·7 × 10^?4 cm^?1. The supertransferred hyperfine interaction was found to be isotropic, absolute value of the corresponding parameter a is 22·1 × 10^?4 cm^?1.     

Ga原子4s~24p及4s~25s态的超精细结构常数

基于相对论多组态Dirac-Fock（MCDF）方法的GRASP2K程序,通过系统的考虑电子关联效应和相对论效应,详细计算了⁷¹Ga原子的基态4s²4p²P_1/2、亚稳态4s²4p²P_3/2及激发态4s⁵s²S_1/2的超精细结构常数.结果表明原子实的极化效应对超精细结构常数起到了重要作用.     

Experimental evidence for far configuration mixing effects on off-diagonal hfs interaction between the (3d+4s) N+2 configurations of free atoms

In our systematic investigations on the hyperfine structure (hfs) of high lying metastable states in 3d-shell atoms we have found evidence for an extraordinary strong far configuration mixing effect on off-diagonal matrix elements between configurations. Using theABMR-LIRF method the hfs of (3d ² 4s ²)³ P ⁴⁷Ti, (3d ³ 4s ²)⁴ P ⁵¹V (3d ⁵ 4s ²)⁴ G ⁵⁵Mn and (3d ⁶ 4s ²)³ H ⁵⁷Fe has been measured. Values found for the effective radial parameters \(a^{k_s k_l } \) of the magnetic dipole interaction disagreed up to 300% with those known from hfs measurements of lower lying multiplets of the same configuration, even when intermediate coupling and electrostatically correlated second order hfs effects within each of the configurations are taken into account. We suggest that the main part of these discrepancies can be explained, if two-body core polarization is considered, which screens the ordinary one-body core polarization parametera _3d ¹⁰ . Preliminary values for the corresponding parameters are given.