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[en] Isotope shift and hyperfine structure of BaI 6s21S0 - 6s6p 1P1 transition (lambda = 533.6 nm) in neutron deficient Ba nuclides (N < 82) have been measured by observing the resonance fluorescence induced by a high resolution tunable CW dye laser in a well collimated atomic beam. Results are now available for 16 Ba isotopes and isomers between A = 140 and A = 126. The experiments aimed at information on nuclear charge radii, magnetic dipole and electric quadrupole moments. The results are discussed in the light of other experimental and theoretical nuclear structure studies of the transitional nuclei with (50 < Z, N < 82) in particular in comparison with results extracted from γ-spectroscopic investigations on the basis of a triaxial-rotor-plus-particle model. The isotope shift discrepancy is quite well described by the droplet model of Myers. A striking and up to now not understandable feature is the negative isomer shift of the g 7/2+ isomer of 129Ba. (orig.)
[de]Isotopieverschiebung und Hyperfeinstruktur des BaI 6s21S0 - 6s6p 1P1 - Uebergangs (lambda = 533.6 nm) wurden in neutronenarmen Ba-Nukliden (N<82) untersucht durch Beobachtung der Resonanzfluoreszenz nach Anregung der Ba-Atome in einem gut kollimerten Atomstrahl mittels eines schmalbandigen durchstimmbaren Dauerstrich-Farbstofflasers. Die Experimente zielten auf Informationen ueber Kernladungsradien, magnetische Dipol- und elektrische Quadrupolmomente. Die gewonnenen Resultate werden im Licht anderer Untersuchungen zur Kernstruktur im Bereich (50 < Z, N < 82) diskutiert, insbesondere im Vergleich zu Ergebnissen, die aus γ-spektroskopischen Messungen auf der Basis eines 'triaxial-rotor-plusparticle'-Modells gewonnen wurden. Die Isotopenverschiebungsdiskrepanz wird relativ gut durch das Droplet-Modell von Myers beschrieben. Eine ueberraschende und noch nicht verstandene Tatsache ist die negative Isomerieverschiebung des g 7/2+-Isomers von 129Ba. (orig.)
[en] We have determined the isomeric ratios in 130Ba(γ, n)129m,gBa, 132Ba(γ, n)131m,gBa and 134Ba(γ, n)133m,gBa photonuclear reactions of natural barium induced by bremsstrahlungs with end-point energies in the giant dipole resonance region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of 60Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors. (author)
[en] The level structure of even-even neutron-rich 140-148Ba isotopes was studied in the framework of the interacting boson model. The reduced transition probabilities B(E2) of these nuclei was calculated. A set of parameters was used in the calculation to approach the values with the measured data. It was pointed out that interacting boson approximations are equitably reliable for the description of spectra and other properties. It was found that there is a rapid transition between spherical and rotational shapes.
[en] The cross sections of (γ, n)-reactions in the range of the Giant Dipole Resonance, leading to the isomeric states h11/2 in odd isotopes of Ba with mass number A=129-137, are presented. An activation method of measurement has been used. The dependence of the isomeric ratio on γ-energy and mass number of the isotopes has been obtained. Different factors influencing the value of the isomeric ratio are discussed. 18 refs., 7 figs., 2 tabs
[en] It was pointed out that the level scheme of the transitional nuclei 124,126,128,130,132,134,136Ba also can be studied by both characteristics (IBM-1 and IBM-2) of the interacting boson model and an adequate point of the model leading to E2 transitions is therefore confirmed. Most of the δ(E2/M1) ratios that are still not known so far are stated and the set of parameters used in these calculations is the best approximation that has been carried out so far. It has turned out that the interacting boson approximation is fairly reliable for the calculation of spectra in the entire set of 124,126,128,130,132,134,136Ba isotopes.
[en] A graphical method for separating mass and volume effects from purely optical isotope shift data is presented and compared with King's ''bunching'' method. Recent experimental data on isotope shifts for a wide range of spectral lines in the naturally abundant isotopes of Ba I and Ba II are analysed. Some agreement is found with muonic X-ray data concerning the nuclear size for the isotopes 136, 137 and 138, but there is disagreement (over 20%) for the other isotopes. The level isotope shifts are further parameterised in terms of a linear model, and the specific mass effect is decomposed into sums of one-electron and two-electron shift parameters with respect to the inert-gas like ground state of Ba III. (orig.)
[en] In summary, commercial quantities of barium carbonate and barium chloride are presently being produced in the United States. Chemical Products Corporation offers both barium carbonate and barium chloride in 50 lb. bags as well as in larger containers. The minimum quantity for direct sale is a 20 ton truckload. Smaller quantities are available through distributors. Commercial quantities of barium hydroxide and barium nitrate are also available through distributors. Chemical Products Corporation sees the emerging use of barium in superconductors as an opportunity and intends to work with superconductor producers to supply the barium salts required in the purity required
[en] The sum peak intensity relative to its single peak was determined in various compounds of 133Ba by the technique of gamma-gamma-ray sum peaks observed in a single HPGe detector. The change in intensity ratio was used to determine the time integral perturbed angular correlation coefficients for BaCl2, Ba(NO3)2, BaSO4, Ba-EDTA, Ba-MES and Ba-BSA compounds. (author) 12 refs.; 2 figs.; 3 tabs