Hyperfine structure in the atomic spectrum of niobium

We report on hyperfine structure measurements in 21 lines of atomic niobium in the spectral region from 640 nm to 870 nm by means of optogalvanic laser spectroscopy and laser induced fluorescence spectroscopy using a hollow cathode discharge and a tunable single-mode cw ring laser. Hyperfine structure constants A and B of altogether 29 excited energy levels were determined, 18 of them for the first time. Received 18 July 2002 / Received in final form 8 November 2002 Published online 4 February 2003 RID="a" ID="a"e-mail: sk@kalium.physik.tu-berlin.de     

Fine and hyperfine structure in the atomic spectrum of niobium

A parametric analysis of the fine and the magnetic dipole hyperfine structure for the three configurations of odd parity 4d³5s5p, 4d⁴5p and 4d²5s²5p was performed. Effective one-electron parameters were determined and theoretical predictions are given for the magnetic dipole hyperfine structure constants A for the levels of these three configurations. Additionally, 12 new energy levels could be found, four of odd and eight of even parity, by re-analysing data for experimental wavelengths of Nb.     

Further experimental investigation of the hyperfine structure in the spectrum of atomic niobium

Laser spectroscopy with either optogalvanic or laser induced fluorescence detection have been employed to measure the hyperfine structure of 25 transitions of atomic niobium in the visible and near infrared spectral range. The magnetic dipole hyperfine interaction constants A of 43 energy levels (22 of even and 21 of odd parity) were determined, 30 of which have been investigated for the first time. The values obtained for the even parity levels are compared with the results of a parametric analysis.     

Hyperfine structure of the atomic osmium spectrum: Superposition of configurations and the effect of nucleus volume

The contributions of the superposition of configurations ns ²5d ⁷6s+ns5d ⁷6sn′s+ns5d ⁷6s ² (n=1–5, n′=7–10) to the parameters of the hyperfine structure a _5d ⁰¹ , a _5d ¹² , a _5d ¹⁰ , a _6s ¹⁰ in the spectrum of the osmium atom Os I are calculated. Nonzero contributions are shown to be made only to the parameters a _5d ¹⁰ and a _6s ¹⁰ . This fact justifies the inclusion of the parameter a _5d ¹⁰ in the semiempirical analysis of experimental values of magnetic dipole constants of the hyperfine structure of the 5d ⁷ s configuration in the spectrum of the osmium atom. The effect of nucleus volume on the parameters of the hyperfine structure in the spectra of osmium isotopes ¹⁸⁷Os and ¹⁸⁹Os is estimated.     

159TbII超精细结构光谱测量

利用具有光谱高分辨和选择性激发等特点的共线快离子束激光光谱学方法研究了^159TbⅡ亚稳态4f^95d^7H8^0和激发态4f^96p3/2(15/2,3/2)的超精细结构光谱，所有光谱线可以很好地分辨；并由实验测量得到的高分辨超精细结构光谱，给出了相应能级的超精细结构常数。     

159159TbII超精细结构光谱测量

利用具有光谱高分辨和选择性激发等特点的共线快离子束激光光谱学方法研究了159TbII亚稳态4f95d7H08和激发态4f96p3/2(15/2, 3/2)的超精细结构光谱,所有光谱线可以很好地分辨;并由实验测量到的高分辨超精细结构光谱,给出了相应能级的超精细结构常数。     

Hyperfine structure and isotope shifts in near-infrared transitions of atomic nitrogen

We have obtained Doppler-free spectra of transitions in the → 2p²(³P) and → multiplets of atomic nitrogen using saturated absorption spectroscopy. These multiplets consist of respectively of seven and eight transitions, and have center of gravity wavelengths of 821 nm and 869 nm. Values for the hyperfine structure coupling constants of all the upper and lower states for these multiplets were obtained for both ¹⁴N and ¹⁵N. Isotope shifts of three transitions in each multiplet were also measured, and a significant J-dependence to the shifts was observed.     

~(159)TbII超精细结构光谱测量

利用具有光谱高分辨和选择性激发等特点的共线快离子束激光光谱学方法研究了159Tb II亚稳态 4 f95 d7H08和激发态 4 f96 p3 / 2 ( 1 5 /2 ,3/2 )的超精细结构光谱 ,所有光谱线可以很好地分辨 ;并由实验测量到的高分辨超精细结构光谱 ,给出了相应能级的超精细结构常数     

Hyperfine spectrum of NaF

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectrum of ²³Na¹⁹F. Coupling constants for the nuclear electric quadrupole interactions, the spin-rotation interactions, the tensor and scalar spin-spin interactions, and their dependence on vibrational and rotational state have been determined.     

Hyperfine spectrum of RbI

The molecular beam electric resonance technique has been used to conduct a high precision examination of the hyperfine spectrum of RbI. Coupling constants for the nuclear electric quadrupole interactions, the spin-rotation interactions, the tensor and scalar spin-spin interactions, and their dependence on vibrational and rotational state have been determined.     

Hyperfine structure in the Gd II spectrum and the nuclear electric quadrupole moment of157Gd

The hyperfine structure of¹⁵⁷Gd was investigated in 20 Gd II lines by means of a photoelectric recording Fabry-Perot interferometer with digital data processing. The hyperfine splitting factors,A andB, were obtained by computer fits to the observed line structures. Using a multiconfigurational set of wave functions in intermediate coupling derived by Wyart, mono-electronic hyperfine parameters were deduced by a parametric treatment. The nuclear electric quadrupole moment of¹⁵⁷Gd was evaluated from the quadrupole interaction of the 5d electron in 4f ⁷ 5d6s, the 5d electron in 4f ⁷ 5d6p, and the 6p electron in 4f ⁷ 5d6p. The three values obtained for the quadrupole moment agree very well. The final result, corrected for Sternheimer shielding, isQ(¹⁵⁷Gd) =1.34(7)·10^?24 cm².     

Hyperfine magnetic anomaly in the atomic spectra of rare-earth elements

Hyperfine-splitting constants in the optical spectra of rare-earth elements, Nd, Eu, Gd, and Lu, were measured using the laser-induced resonance fluorescence in a low-divergence atomic beam. Values of the hyperfine magnetic anomaly for different atomic levels were determined by comparing the ratios of the magnetic dipole constants of neighboring isotopes with odd numbers of protons or neutrons. The relation of these values to the special features of the atomic and nuclear structure of the investigated elements is discussed.     

The oxidation of niobium and the structure of niobium oxides

Results are given for the oxidation kinetics of niobium in air at 500–1000 °C, together with x-ray data on the oxides; -Nb₂O₅ (orthorhombic) is formed up to 850 °C, and above this -Nb₂O₅, also orthorhombic but with lattice constants nearly twice as large. The physics of the oxidation is discussed.     

Hyperfine structure investigations in the4F9/2 atomic ground state of191Ir and193Ir

The5d ⁷6s^{2 4}F_9/2 atomic ground state of¹⁹¹Ir and¹⁹³Ir has been studied using the atomic-beam magnetic-resonance method. The results are:¹⁹³Ir:g _J(⁴F_9/2)=1.29694 (3)¹⁹¹Ir:Δv(⁴F_9/2; F=6?F=5)=659.26496 (12) MHzΔv( ⁴F_9/2; F=5?F=4)=189.44002 (09) MHzΔv( ⁴F_9/2; F=3?F=4)=84.05040 (80) MHzA=57.52148 (04) MHzB=471.20425 (57) MHzC=?0.020 (30) kHz¹⁹³Ir:Δv( ⁴F_9/2; F=6?F=5)=660.09043 (12) MHzΔv( ⁴F_9/2; F=5?F=4)=224.47848 (13) MHzΔv( ⁴F_9/2; F=?F=4)=33.53453 (89) MHzA=62.65556 (05) MHzB=426.23546 (64) MHzC=0.020 (30) kHz Using the magnetic dipole moments known by NMR-technique [1] we obtained for the electric quadrupole moments as calculated from the hyperfine interaction constantsA andB:Q(¹⁹¹Ir)=0.78 (20) barns,Q(¹⁹³Ir)=0.70 (18) barns (uncorrected for core polarization effects). A calculation of the hyperfine anomaly yields:₁₉₁ Δ ₁₉₃=?0.00023 (10). The ratio of theB factors which should be the same as for the quadrupole moments turned out to be:B(¹⁹¹Ir)/B(¹⁹³Ir)=Q(¹⁹¹Ir)/Q(¹⁹³Ir)=1.105502(3).     

Hyperfine structure of lithium-like scandium

The hyperfine structure of the ground state of the lithium-like scandium ion (Z = 21) is considered. The effects of electron-electron interaction are taken into account in the first order in 1/Z using the quantum electrodynamic perturbation theory and in higher orders using the method of configuration interaction in the Dirac-Fock-Sturm basis. One-loop radiative corrections are calculated in all orders in αZ with an effective local screening potential. The corrections for the finite nuclear size and the distribution of the magnetic moment over the nucleus have been refined.     

Hyperfine structure in internal rotor molecules

The theory of magnetic hyperfine interactions in internal rotor molecules with one internal degree of freedom has been developed as basis for the interpretation of hyperfine structure in the microwave spectra of these molecules. It has been shown that the internal rotation modifies the familiar nuclear spin-spin and spin-rotation interactions. Explicit expressions for the hyperfine energy matrix elements and coupling constants are derived for the methanol molecule.     

Hyperfine and isotopically invariant parameters of the GeS microwave spectrum

The complete set of microwave data for the nine isotopic species of the GeS molecule, available in literature, is reduced to molecular parameters by a nonlinear least-squares fit. All the hfs lines due to ⁷³Ge ($\text{I =}\text{9}\text{2}$) and ³³S ($\text{I =}\text{3}\text{2}$) are included in this fit. Watson's expressions of Dunham coefficients, including corrections to the Born-Oppenheimer approximation, are used. Contributions from off-diagonal terms are taken into account in the hfs Hamiltonian which is numerically diagonalized. A set of 12 hyperfine and isotopically invariant parameters is obtained and compared with previous determinations. It is shown that the accuracy of the hfs parameters is improved by one order of magnitude by the global treatment of all the data.