Die Hyperfeinstruktur des 6s 6p 3 P 1-Zustandes von171Yb und173Yb

The hyperfine structure of the 6s 6p ³ P ₁ state of¹⁷¹Yb and¹⁷³Yb has been investigated by the level crossing technique and by optical double resonance. The following results for the magnetic hfs splitting constantA and for the electric quadrupole interaction constantB have been obtained:A(¹⁷¹Yb)=3959.1(14)Mc/sec;A(¹⁷³Yb)=?1094.7(6) Mc/sec;B(¹⁷³Yb)=?826.9(9) Mc/sec. The hyperfine structure anomaly of the isotopes¹⁷¹Yb and¹⁷³Yb was determined to beΔ=?0.36(3)%.     

Doppelresonanzexperimente zur Untersuchung der Hyperfeinstruktur des 6s6p 3 P 1-Zustandes von171Yb und173Yb

For the odd Yb isotopes¹⁷¹Yb and¹⁷³Yb the hyperfine splitting of the 6s6p ³ P ₁ state has been measured by optical double resonance in zero magnetic field. Taking into account second order corrections due to the influence of the 6¹ P ₁ and 6³ P _0,2 states, the following results for the magnetic splitting constantA and the electric quadrupole interaction constantB have been derived: A(¹⁷¹Yb)=3958.228 (60) Mc/s, A(¹⁷³Yb)=?1094.318 (35) Mc/s, S(¹⁷³Yb)=?825.904 (85) Mc/s. The hyperfine structure anomaly of the isotopes¹⁷¹Yb and^{171 173}Yb was determined to be Δ=?0.352 (10)%.     

Analysis of the isotope shifts and hyperfine structure in the 3 988 Å (6s6p 1 P 1↔6s 2 1 S 0) YbI line

High-resolution laser spectroscopy using a pulsed dye-laser acting on a collimated atomic beam has been used to determine the isotope shifts in the 3 988 Å YbI line. The following results have been obtained:Δσ(176, 174)=?509(4)MHz,Δσ (174, 173)=?291(10) MHz,Δσ(174, 172)=?530(4) MHz,Δσ(172, 171)=?414(5) MHz andΔσ(172, 170)= ?665(10) MHz. The sign of the magnetic dipole interaction constant in the¹ P ₁ state for¹⁷¹Yb is found to be negative,a(¹ P ₁, 171)=?213.4(3.0) MHz. The electric quadrupole interaction constant for¹⁷³Yb in the¹ P ₁ state is found to beb(¹ P ₁, 173)=605(20) MHz.     

Präzisionsmessung der Kerndipolmomente von Ba135 und Ba137 mit optischem Pumpen

The nuclear Zeeman levels of the ground state of Barium (6s^{2 1}S₀, F=I=3/2) were polarized by means of optical pumping with the resonance line (6s^{2 1}S₀?6s 6p¹P₁, λ=5535 Å). The magnetic field was calibrated by means of optical pumping of sodium. The magnetic moments, calculated from the nuclear Hf-Zeeman-transitions at 228 Gauss are μ₁₃₅=0,83651 (6) μ_N μ₁₃₇=0,93573 (6) μ_N (with diamagnetic correction). With the results of nuclear induction in BaCl₂ we calculate the chemical shift to be (8.6±1.0)·10^?4. The ratio of the nuclear moments is μ₁₃₇/μ₁₃₅=1.11862 (3) in agreement with the measurements in BaCl₂.     

Hyperfine structure investigations in Sm II by collinear laser spectroscopy and nuclear moments of151Sm

We have measured the hfs of the Sm II linesλλ=656.9 nm and 657.1 nm by collinear laser spectroscopy. From the a-and b-values the ratios of nuclear magnetic dipole and electric quadrupole moments are derived. For¹⁵¹Sm we obtain μ(151)=?0.3622(5) μ_n and Q(151)=0.52 (5) b.     

Atomic beam magnetic resonance investigations in the3 F 2 Ground State of177Hf,179Hf and180Hf

The 5d ²6s ^{2 3} F ₂ ground state of¹⁷⁷Hf,¹⁷⁹Hf and¹⁸⁰Hf has been studied using the atomic beam magnetic resonance method. The atomic beam was produced by an universal evaporation technique described in a previous paper. The results are¹⁸⁰Hfg _j (³ F ₂)=0.695812 (10)¹⁷⁷Hf Δv(³ F ₂;F=11/2?F=9/2)=991.7917 (10) MHz Δv(³ F ₂;F=9/2?F=7/2)=477.0081 (10) MHz Δv(³ F ₂;F=7/2?F=5/2)=162.8890 (10) MHz¹⁷⁹HfΔv(³ F ₂;F=13/2?F=11/2)=82.1320 (10) MHz Δv(³ F ₂;F=11/2?F=9/2)=392.8498 (10) MHz. The magnetic dipole and electric quadrupole moments of the¹⁷⁷Hf and¹⁷⁹Hf nuclear ground states as calculated from these hyperfine structure measurements are the following: μ(177)=0.75(8)μ _k , Q(177)=4.34 (65) barns μ(179)=?0.61 (6)μ _k , Q(179)=4.90 (75) barns.     

Nuclear magnetic resonance on oriented189,191 Pt in iron

Nuclear magnetic resonance measurements have been performed for¹⁸⁹Pt and¹⁹¹Pt oriented at 7 and 15 mk in iron host. The magnetic hyperfine splitting frequencies, ν=¦μB_HF/Ih¦, of the¹⁸⁹Pt and¹⁹¹Pt ground states were determined to be 277.61(5) and 319.88(3) MHz. With the hyperfine field of B_HF=-1280(26) kG the nuclear magnetic moments were deduced to be: ¦μ(¹⁸⁹Pt;3/2^?)¦=0.427(9) μ^N; ¦μ(¹⁹¹Pt,3/2^?) ¦=0.492(10) μ_N. The effective spinlattice relaxation time for¹⁹¹PtFe at 7 mK in a polarizing magnetic field of 2 kG has been found to be 30(2) s using a single-exponential fit.     

Bestimmung der Kerndipolmomente von171Yb und173Yb durch optisches Pumpen

The nuclear Zeeman levels of the odd isotopes of Ytterbium (¹⁷¹Yb,¹⁷¹ I=1/2;¹⁷³Yb,¹⁷³ I=5/2) were polarized in the atomic ground state (6s ^{2 1} S ₀) by means of optical pumping with the resonance line (6s ^{2 1} S ₀ ? 6s6p ¹ P ₁,λ=3988 å). The magnetic moments, calculated from the nuclear Hf-Zeeman transitions in a magnetic field of 228 Gauss are¹⁷¹ Μ _I=0.49188 (2)Μ _K ¹⁷³ Μ _I=0,67755 (3)Μ _K (with diamagnetic correction applied).     

Winkelkorrelationsmessungen an88Sr

The γγ ande _? ^KL γ directional correlations have been measured for the (898–1836) keV cascade in⁸⁸Sr following the decay of⁸⁸Y. The observed correlation coefficients areA ₂₂(γγ)=?0.0784±0.0042 andA ₂₂(e _? ^KL γ)=0.0102±0.0046. The γγ experiment is consistent with a mixing ratio δ(γ)=0.009±0.005 for the 898 keV transition. Using the result of thee _? ^KL γ experiment the most probable value of the ratio of the penetration matrix element to the normal γ-ray matrix element was determined to be η=0.03±0.30 showing a normal conversion process. This penetration parameter agrees with a hindrance factorH _W(E1)=2.1 · 10^?3 for theE1 transition.     

Nature of the pygmy resonance in continuous <Emphasis Type="Italic">γ</Emphasis> spectra

Two-step-cascade spectra of the ¹⁷¹Yb(n, γγ)¹⁷²Yb reaction have been measured using thermal neutrons. They are compared to calculations based on experimental values of the level density and radiative strength function obtained from the ¹⁷³Yb(³He, aγ)¹⁷²Yb reaction. The multipolarity of a 6.5(15) μ _N ² resonance at 3.3(1) MeV in the strength function is determined to be M1 by this comparison.     

An investigation of theL 2-L 3 Coster-Kronig transition probability for 63≦Z≦96

Nuclear spin polarization in the 4f ¹⁴6s ^{2 1} S ₀ ground state of¹⁷⁵Lu⁺(I=7/2) ions is achieved by optical pumping with the resonance line (¹ S ₀-¹ P ₁,λ=261.5 nm). Nuclear magnetic resonance of the free ions in He buffer gas yields for the magnetic dipole momentμ(¹⁷⁵Lu)=2.2240(11)μ _n (with diamagnetic correction). This value can be used for a more accurate determination of the magnetic dipole moments of other Lu isotopes from knownA factor ratios. A comparison with nuclear induction measurements in solids results in the chemical shiftsδ(LuB₁₂)=?23(5)·10^?4 andδ(LuSb)= ?31(5)·10^?4.     

Electric quadrupole and magnetic dipole moments of the first excited 2+ states of186Os and188Os

The spectroscopic quadrupole moments and the magnetic dipole moments of the lowest 2⁺ states in¹⁸⁶Os (137 keV) and¹⁸⁸Os (155 keV) have been determined by Mößbauer transmission experiments. The electric quadrupole momentsQ ₂₊(Os 186)=? (1.80±0.22) b andQ ₂₊(Os 188)=?(1.81±0.24) b as well as their ratioQ ₂₊(Os 188)/Q ₂₊(Os 186)=1.00±0.07 within the limits of error agree withB(E2) data, if a comparison on the basis of the rotational model is made. For the g-factors and their ratio g₂₊(Os 186)=0.281±0.008, g₂₊(Os 188)=0.305±0.015 andg ₂₊(Os 188)/g ₂₊(Os 186)=1.08±0.05 was obtained. All results are compared with recent model calculations.     

Nuclear orientation measurements of the magnetic dipole moments of the 11/2− Isomeric states in129Xe,131Xe and133Xe

The low-temperature nuclear orientation technique was used to measure the magnetic moments of¹²⁹ mXe,¹³¹ mXe and¹³³ mXe implanted in iron by isotope separator. The magnitudes of the magnetic dipole moments, extracted from the gamma-ray anisotropy measurements areμ=?0.80(10)μ _N for^129m Xe,μ=?0.80(10)μ _N for¹³¹Xe andμ=?0.87(12)% for¹³³Xe. The results for these 11/2^? isomers agree with theoretical calculations by the spin polarization procedure using wave functions from the pairing-plus-quadrupole model.     

Raman spectroscopy of BaTiO3/(Ba,Sr)TiO3 superlattices

A series of BaTiO₃/Ba_{1 ? x} Sr _x TiO₃ (BT/BST) superlattices were prepared by pulsed laser deposition on MgO substrates with a constant period of 80 Å (40 Å BT and 40 Å BST) and varying compositions of the BST layer so that the Ba/Sr concentration ratios were 0/100, 30/70, 40/60, 50/50, 60/40, 70/30, 100/0. The soft mode E(1TO) of the polarized Raman spectra transformed depending on the Ba/Sr ratio in the BST layer. As the Sr concentration in the BST layers increased from 0 to 100%, the E(1TO) soft mode half-width varied from 171 to 103 cm^?1 and its frequency increased from 31 to 109 cm^?1 due to the interaction between the epitaxial layers forming the superlattices.     

Magnetic dipole moments of excited states of105Pd and other spectroscopic investigations in the decay of105g Ag

The IPAC-method has been used with the external magnetic field of 9.0 T of a split coil superconducting magnet and with the internal field of PdFe for a measurement of magnetic moments of¹⁰⁵Pd states populated in the decay of 41.29d¹⁰⁵Ag. The results are:μ _7/2 (645 keV)=?1.49(9) nmμ _5/2 (319 keV)=+0.95(20) nmμ _3/2 (280keV)=?0.074(13) nm. The half-life of the 645 keV state has been redetermined by use of cooled thallium free Nal detectors asT _1/2 (645 keV)=126(2) ps. γ-γ directional correlations were measured with a system of three large Ge planar diodes for the cascades 443–645 keV, 332–319 keV, 393–280 keV, and 64–280 keV and analyzed in terms of dipole quadrupole mixing ratios of theγ-lines involved. The spin of the 673 keV state was derived as l/2⁺.     

Nuclear orientation of171Lu and173Lu

The decays of¹⁷¹Lu and¹⁷³Lu have been studied by means of nuclear orientation. External perturbations of two¹⁷¹Yb levels have been observed. Unambiguous spin assignments have been made for several levels in¹⁷¹Yb and mixing ratios of the transitions in¹⁷¹Yb and¹⁷³Yb have been deduced. The properties of the¹⁷¹Yb and¹⁷³Yb rotational bands have been studied using the quasiparticle-phonon model including a Coriolis interaction.     

Mössbauer study of the electromagnetic properties of the 69.6-keV level in Os 189

The 69.6-keV level with spin 5/2^? in¹⁸⁹Os was investigated by the recoilless resonance absorption technique. Its magnetic moment was found to beμ (5/2)=(0.977±0.014)μ _N. From the measured ratio of the excited and ground-state electric quadrupole moments,Q(5/2)/Q(3/2)=?0.79±0.09, the excited-state quadrupole momentQ(5/2)=?(0.72±0.11)b could be derived. TheE2/M1 mixing parameter of the 69.6-keV ground-state transition was found to beδ=+0.69±0.10. The results are interpreted in terms of two low-energy rotational bands with strong Coriolis mixing.     

Mössbauer effect study of hyperfine interactions in145Nd

The magnetic hyperfine splitting of the 72.5 keV γ rays of¹⁴⁵Nd was investigated in intermetallic compounds of Nd and in the paramagnetic salts Nd _x Y _1-x Cl₃·6H₂O (withx=0.02 andx=0.05) at 4.2 K. With the magnetic hyperfine tensorA of Nd_0.01Y_0.99Cl₃·6H₂O known from EPR spectroscopy, the analysis of the unresolved magnetic hyperfine spectra yieldsI _e =5/2 for the spin of the 72.5 keV state, in contradiction to a previous result. The multipolarity of the 72.5 keV γ transition was found to be essentiallyM1 with δ²=0.010±0.014, and the magnetic moment of the 72.5 keV state was determined as μ(5/2)=?0.319±0.004 nm. For various divalent and trivalent Nd compounds as well as for metallic Nd the isomer shift IS of the 72.5 keV γ line was measured. A value for the change of the mean square nuclear charge radius during the 72.5 keV γ transition of Δ〈r ²〉=+(1.9±0.9)·10^?3fm² was deduced using electron density differences from free-ion Hartree-Fock calculations.     

Mössbauer studies and nuclear quadrupole moments of186, 188, 189, 190 Os

Mössbauer transmission experiments with the 137, 155, 69 and 187 keV gamma rays of^{186, 188, 189, 190}Os, respectively, yielded the electric quadrupole splitting of these gamma resonance lines in OsO₂ and OsP₂. From the results the following ratios of quadrupole moments were derived:Q ₂ ⁺(¹⁸⁶Os, 137 keV):Q ₂ ⁺(¹⁸⁸Os, 155keV):Q ₂ ⁺(¹⁹⁰Os, 187 keV):Q _3/2 ^?(¹⁸⁹Os, g.s.)=(+1.100±0.020): 1.0:(+0.863±0.051): (?0.586±0.011) andQ _5/2 ^?(¹⁸⁹Os, 69 keV)/Q _3/2 ^?(¹⁸⁹Os, g.s.)=?0.735 ±0.012. The ratios for^{180, 188, 190}Os are, within their limits of error, in agreement with the expectation of the rotational model, indicating that the pairing-plusquadrupole model calculations of Kumar and Baranger predict too rapid a transition form rotational to vibrational nuclei. Applying this argument to¹⁸⁶Os in particular and using the measured ratios, one obtains a set of values for the quadrupole moments themselves, namelyQ ₂ ⁺ (¹⁸⁶Os)=?(1.50 ± 0.10)b,Q ₂ ⁺(¹⁸⁸Os)=?(1.36± 0.09) b,Q ₂ ⁺ (¹⁹⁰Os)=?(1.18 ± 0.08) b,Q _3/2 ^?(¹⁸⁹Os)=+ (0.80 ± 0.06) b, andQ _5/2 ^? (¹⁸⁹Os)=? (0.59 ± 0.05) b. For the electric field gradient at Os nuclei in Re metal a value ofV _zz=?(3.3 ± 0.6) · 10¹⁷ V/cm² was found. A measurement with a magnetically split source yielded δ=+ 0.685 ± 0.025 for theE2/M1 mixing parameter of the 69 keV transition of¹⁸⁹Os,g _5/2 ^?/g _3/2 ^?=0.895 ± 0.006 for the ratio of theg-factors of the 69 keV state and the groundstate, andH _i=?(1135 ± 20) kOe for the hyperfine field at Os nuclei in an iron matrix.     

Optical determination of the nuclear moments of137La

Using the reactor-produced lanthanum isotope ₅₇ ¹³⁷ La, the hyperfine structure (hfs) of the transition La I, 5d ² 6p z ⁴ G ₁₁ ^2/0 ?5d ² 6s a ⁴ F _9/2, λ=6250 Å and La I, 5d ² 6p z ² H ₁₁ ^2/0 ? 5d ² 6s a ²G_9/2, λ=6266 Å were measured by means of a Fabry-Pérot interferometer. The nuclear spin I (¹³⁷La)=7/2, already theoretically estimated by earlier authors, was confirmed. The nuclear magnetic dipole moment μ_I(¹³⁷La)=+ 2.690 (6) n.m. and the electric quadrupole momentQ(¹³⁷La)=+ 0.26 (8) · 10^?24 cm² were determined from the ratios of the hfs interaction constantsA andB of¹³⁷La and the natural¹³⁹La.