[en] The isotopic composition of nanogram quantities of osmium was measured by using an inductively coupled plasma source mass spectrometer. Sensitivity was enhanced a factor of ∼100 by the use of an osmium tetraoxide vapor generator rather than nebulization of solution. For samples ≤5 ng, the ratios ¹⁹⁰Os/¹⁹²Os, ¹⁸⁹Os/¹⁹²Os, and ¹⁸⁸Os/¹⁹²Os were determined to better than +/- 0.5% (1σ/sub m/) precision. For the minor isotopes, the ratios ¹⁸⁷Os/¹⁹²Os and ¹⁸⁶Os/¹⁹²Os were determined to +/-1%, and ¹⁸⁴Os/¹⁹²Os (4 x 10^-4) was determined to ∼10%. Isotope ratios for common osmium are reported

No abstract available

[en] Doppler-free isotope shift measurements of the stable even ^184-192Os and ^187,189Os odd isotopes have been performed for the first time on the 5d⁶6s²⁵D₄^→5d⁶6s6p⁷F₄ (305.9 nm) transition in the neutral atom by atomic beam laser spectroscopy and on the ionic 5d⁶6s⁵D_9/2^→5d⁶6p⁶D_7/2 (228.2 nm) transition by fast collinear ion-laser spectroscopy. The measurements were carried out in Manchester and at the IGISOL facility in Jyvaeskylae in Finland, respectively. The results presented are the most precise measurements to-date of the absolute isotope shifts.

[en] The angular frequency of the lowest-frequency band crossing in Os nuclei is dominated by a rotational-aligned configuration which is sensitive to the position of the 1/2⁺[660] Nilsson neutron configuration relative to the Fermi surface. The position of this configuration, which is traced from ¹⁷⁶Os to ¹⁸⁶Os, is dependent upon the hexadecapole deformation. Values of epsilon₄ approx. >= 0.07 are indicated for ^182-186Os. (orig.)

[en] A negative thermal ionization technique using a Faraday cup as detector is presented, which allows precise isotope ratio measurements of osmium. For the major isotopes the relative standard deviation is in the range of 0.004% to 0.07%. Sample amounts down to 1 ng were loaded as hexachloroosmic acid. From the results it is concluded that also sample amounts in the pg range will result in sufficient ion currents of OsO₃^-, avoiding an electron multiplier as detector. H₂OsCl₆ was chosen because this compound is the most suitable chemical form after separation of osmium from geological samples. The introduction of oxygen or freons into the ion source enhances the emission of OsO₃^- ions by a factor of up to more than ten. Ionization efficiencies of more than 30% are obtained by using oxygen. The stability of the ion current is better in the case of oxygen than in the case of freons. However, both compounds are stabilizing the high voltage potentials of the optical ion lenses in the ion source, a permanent problem in NTI-MS. The described isotope ratio measurement is an important improvement for Re/Os dating of terrestrial and extraterrestrial samples. (orig.)

No abstract available

[en] Short communication

[en] Doubly decoupled structures in doubly odd deformed nuclei are reexamined and shown to be composed of a pseudo-spin aligned neutron and a decoupled proton. (orig.)

[en] Osmium isotopes in the natural isotopic mixture are separation by gas centrifuge technology. OsO₄ is chosen as the process gas. The relationship γ_ij=γ₀^ΔA_ij is verified by experiments using a single centrifuge, and the real value of γ₀ is obtained by fitting. Based on this, a four-stage cascade is degigned to separate ¹⁹²Os. The results show that the abundance of ¹⁹²Os is more than 99%. (authors)

[en] Yrast states with spins up to about 22 h have been identified in ¹⁷⁶Os, ¹⁷⁸Os, ¹⁸⁰Os and ¹⁸²Os. In each case anomalies are observed in the yrast sequence. The yrare extensions of the ground state and Stockholm bands in ¹⁷⁸Os and ¹⁸⁰Os are also observed and the magnitude of the yrast-yrare interaction matrix elements extracted and discussed