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Nuclear Data Sheets for A = 112

Evaluated nuclear structure and decay data for all nuclei within the A = 112 mass chain are presented. The experimental data are evaluated and best values for level and gamma-ray energies, quantum numbers, lifetimes, gamma-ray intensities, and other nuclear properties are recommended. Inconsistencies and discrepancies that exist in the literature are noted. This work supersedes the earlier evaluation by D. De Frenne and E. Jacobs (1996De55), published in Nuclear Data Sheets79, 639 (1996)

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

A test for correction made to spin systematics for coupled band in doubly-odd nuclei

Systematic Spin Assignments were generally made by using the argument that the energy of levels is a function of neutron number. In the present systematics, the excitation energy of the levels incorporated the effect of nuclear deformation and signature splitting. The nuclear deformation changes toward the mid-shell, therefore a smooth variation in the excitation energy of the levels is observed towards the mid-shell, that intended to make systematics as a function of neutron number towards the mid-shell. Another term “signature splitting” that push the energy of levels for odd- and even-spin sequences up and down, caused the different energy variation pattern for odd- and even-spin sequences. The corrections made in the spin systematics were tested for the known spins of various isotopic chain. In addition, the inconsistency in spin assignments made by the spin systematics and other methods of the configuration πh{sub 11/2} ⊗ νh{sub 11/2} band belonging to {sup 112,114,116}Cs, {sup 126}Pr, and {sup 138}Pr, as an example, was resolved by the correctionmade in the present spin systematics.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Precursor routes to quaternary intermetallics: Synthesis, crystal structure, and physical properties of clathrate-II Cs{sub 8}Na{sub 16}Al{sub 24}Si{sub 112}

A new quaternary clathrate–II composition, Cs{sub 8}Na{sub 16}Al{sub 24}Si{sub 112}, was synthesized by kinetically controlled thermal decomposition (KCTD) employing both NaSi and NaAlSi as the precursors and CsCl as a reactive flux. The crystal structure and composition of Cs{sub 8}Na{sub 16}Al{sub 24}Si{sub 112} were investigated using both Rietveld refinement and elemental analysis, and the temperature dependent transport properties were investigated. Our results indicate that KCTD with multiple precursors is an effective method for the synthesis of multinary inorganic phases that are not easily accessible by traditional solid-state synthesis or crystal growth techniques. - Graphical abstract: Quaternary Cs{sub 8}Na{sub 16}Al{sub 24}S{sub 112} clathrate–II was synthesized for the first time by kinetically controlled thermal decomposition (KCTD) employing a NaSi+NaAlSi precursor mixture with CsCl as the reactive flux, and the structural and transport properties were investigated. Our approach demonstrates a new synthetic pathway for the synthesis of multinary inorganic compounds. This work reports the exploration of a new clathrate composition as this class of materials continues to be of interest for thermoelectrics and other energy-related applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Strength and texture of sodium chloride to 56 GPa

The strength and texture of sodium chloride in the B1 (rocksalt) and B2 (cesium chloride) phases were investigated in a diamond anvil cell using synchrotron X-ray diffraction in a radial geometry to 56 GPa. The measured differential stresses within the Reuss limit are in the range of 0.2 GPa for the B1 phase at pressure of 24 GPa and 1.6 GPa for the B2 phase at pressure of 56 GPa. A strength weakening is observed near the B1-B2 phase transition at about 30 GPa. The low strength of NaCl in the B1 phase confirms that it is an effective pressure-transmitting medium for high-pressure experiments to ~30 GPa. The B2 phase can be also used as a pressure-transmitting medium although it exhibits a steeper increase in strength with pressure than the B1 phase. Deformation induces weak lattice preferred orientation in NaCl, showing a (100) texture in the B1 phase and a (110) texture in the B2 phase. Lastly, the observed textures were evaluated by viscoplastic self-consistent model and our results suggest {110} <11¯0 > as the slip system for the B1 phase and {112} <11¯0 > for the B2 phase.

36 MATERIALS SCIENCE↗

Modern status of photonuclear data

The reliability of experimental cross sections obtained for (γ, 1n), (γ, 2n), and (γ, 3n) partial photoneutron reactions using beams of quasimonoenergetic annihilation photons and bremsstrahlung is analyzed by employing data for a large number of medium-heavy and heavy nuclei, including those of {sup 63,65}Cu, {sup 80}Se, {sup 90,91,94}Zr, {sup 115}In, {sup 112−124}Sn, {sup 133}Cs, {sup 138}Ba, {sup 159}Tb, {sup 181}Ta, {sup 186−192}Os, {sup 197}Au, {sup 208}Pb, and {sup 209}Bi. The ratios of the cross sections of definite partial reactions to the cross section of the neutron-yield reaction, F{sub i} = σ(γ, in)/σ(γ, xn), are used as criteria of experimental-data reliability. By definition, positive values of these ratios should not exceed the upper limits of 1.00, 0.50, 0.33,... for i = 1, 2, 3,..., respectively. For many nuclei, unreliable values of the above ratios were found to correlate clearly in various photon-energy regions F{sub i} with physically forbidden negative values of cross sections of partial reactions. On this basis, one can conclude that correspondent experimental data are unreliable. Significant systematic uncertainties of the methods used to determine photoneutron multiplicity are shown to be the main reason for this. New partial-reaction cross sections that satisfy the above data-reliability criteria were evaluated within an experimental–theoretical method [σ{sup eval}(γ, in) = F{sub i}{sup theor} (γ, in) × σ{sup expt}(γ, xn)] by employing the ratios F{sub i}{sup theor} (γ, in) calculated on the basis of a combined photonuclear-reaction model. It was obtained that cross sections evaluated in this way deviate substantially from the results of many experiments performed via neutron-multiplicity sorting, but, at the same time, agree with the results of alternative activation experiments. Prospects of employing methods that would provide, without recourse to photoneutron-multiplicity sorting, reliable data on cross sections of partial photoneutron reactions are discussed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗