No abstract available

[en] The mixed-valence states in Cs₂Au(I)Au(III)X₆ (X=Cl, Br, I) were studied by Moessbauer spectroscopy of ¹⁹⁷Au. In Cs₂Au(I)Au(III)X₆, the difference between the valence state of Au(I) and that of Au(III) decreases as the character of the Au-X bond becomes highly covalent, because the charge-transfer interaction between Au(I) and Au(III) through the bridging halogen becomes stronger. In the cubic phase of bromo-bridged complex, the valence state of Au is considered to be II which has been unknown for the Au complexes having infinite chains. (author)

[en] The hal-life (1.2+-0.1ns) of the 789.9keV 9/2^- level in ¹⁹³Au is measured. The retardation of the deexciting M1 and E2 transitions suggests that this 9/2^- state, as well as those found in 187, 189, 191 gold nuclei, issues from the hsub(9/2) orbit. The average shape of the Au nuclei in these states and of their even Pt cores is interpreted with the particle + asymmetric rotor model

[en] This thesis describes nuclear spectroscopy aspects of nuclear orientation in the odd-A gold isotopes ₁₉₁Au, ₁₉₃Au, ₁₉₅Au and ₁₉₇Au. These isotopes lie in a transitional region between the spherical nuclei in the lead region and the strongly deformed rare earth isotopes. Following a general introduction to nuclear orientation, the experimental arrangement is described. A new technique is presented that applies in-beam recoil implantation inside the refrigerator itself and this was applied to the case of ₁₉₁Au. The three other gold isotopes were oriented using a conventional dilution refrigerator. The nuclear orientation experiments concerning 11/2^- isomers of the isotopes are described. The long-lived isomeric states were oriented using the large hyperfine field of gold in iron. Higher lying levels were studied by nuclear orientation of the Hg parent states. (Auth./C.F.)

[en] The hyperfine structure and isotope shifts of short-lived gold isotopes with 185≤A≤190 and the 11/2^- isomer of ¹⁸⁹Au have been investigated by application of on-line resonance ionization mass spectroscopy. A detection efficiency of ε=10^-8 for gold atoms was observed at a background of about one event per 1000 laser shots. The deduced charge radii show a drastic change between A=187 and A=186 which is interpreted as an onset of strong deformation (β₂ ≅ 0.25) in ¹⁸⁶Au and ¹⁸⁵Au due to the influence of the π1h_9/2 intruder orbital. (orig.)

[en] The isotope shift between ¹⁹⁷Au (stable) and the radioactive Au isotopes ¹⁹⁰Au, ¹⁹¹Au, ¹⁹²Au and ¹⁹³Au were determined by resonance fluorescence spectroscopy in the 6s²Ssub(1/2)-6p²Psub(1/2). lambda=267,6 nm line. The unstable Au isotopes were produced at the ISOLDE mass separator at CERN. The nuclei were investigated semi on-line in a resonance vessels, heated to 1,400⁰C. The results are deltaνsup(190,197)=11.12(39) GHz. deltaνsup(191,197)=-9.67(12) GHz, deltaνsup(192,197)=-8.32(15) GHz, deltaνsup(193,197)=-6.29(11) GHz, corresponding to a change of the mean-square charge radius by delta< r²>sup(190,197)=0.261(12) fm, delta< r²>sup(191,197)=0.227(5) fm, delta< r²>sup(192,197)=0.195(5) fm, delta< r²>sup(193,197)=0.148(4) fm. (orig.)

No abstract available

[en] Levels in ^189191193Au have been studied by radioactive decay of isotopically separated ^189191193Hg. The systematics of the levels are followed from ¹⁹⁵Au to ¹⁸⁹Au and show a remarkable insensitivity to neutron number. The hsub(11/2) bands are identified and provide a critical test of the model of a single-j nucleon subject to rotation-aligned coupling to an asymmetric core. Within the framework of the model the triaxial degree of freedom appears to be very stable. (Auth.)

[en] A method for experimental studying of metal sputtering by reactor neutrons is described which permits to determine the quantity of sputtered atoms, their isotope ratio and to compare the latter with the sputtered target isotope ratio. A considerable difference is found between the isotope ratio of the sputtered substance and that of the targets, which points to the difference between the emission mechanisms of stable and radioactive gold isotopes

[en] Highlights: • The introduction of Au₁₃(8e) into GUM [29] is a supplement to understand gold clusters. • Based on Au₁₃(8e) the structural evolution of experimental clusters can be elucidated. • Following the structural evolution, a new cluster with high stabilities is predicted. A grand unified model (GUM) has been proposed recently to understand structure anatomy and evolution of liganded gold clusters. In this work, besides the two types of elementary blocks (triangular Au₃(2e) and tetrahedral Au₄(2e)), we introduce a secondary block, namely, the icosahedral Au₁₃ with 8e valence electrons, noted as Au₁₃(8e). Using this secondary block, structural anatomy and evolution of a special group of liganded gold nanoclusters containing icosahedral Au₁₃ motifs can be conveniently analyzed. In addition, a new ligand-protected cluster Au₄₉(PR₃)₁₀(SR)₁₅Cl₂ is predicted to exhibit high chemical and thermal stability, suggesting likelihood of its synthesis in the laboratory.