High-spin states in123Te

The¹⁰Be(¹²C,¹⁴O)⁸He-reaction has been used to study the levels of⁸He. In addition to the known excited state of⁸He at E _x =3.6MeV, withJ ^π=2⁺, three additional states were found at excitation energies of 4.54(25)MeV, 6.03(10)MeV and 7.16(4)MeV.     

腐植酸物质的表面增强拉曼散射

腐植酸物质的表面增强拉曼散射Ｅ．Ｊ．Ｌｉａｎｇ（梁二军）１，３，Ｙ．Ｈ．Ｙａｎｇ（杨育晖）３，Ｗ．Ｋｉｅｆｅｒ３１．郑州大学物理工程学院郑州４５００５２２．中国科学院化学研究所北京１０００８０３．ＩｎｓｔｉｔｕｔｆｕｅｒＰｈｙｓｉｋａｌｉｓｃｈｅＣｈ...     

Electron Capture Probabilities in105Ag

TheK-electron capture probabilities for the 1/2^? → 3/2^? and 1/2^? → 1/2⁺ transitions in the decay of¹⁰⁵Ag were measured for the first time using the sum coincidence method. The experimental P_K values were estimated to be 0.824 ± 0.042 and 0.851 ±0.046 for the allowed and first-forbidden beta transitions, respectively in agreement with the theory. The P_L experimental values to these two levels were also computed using the experimental P_L/P_K values reported by earlier authors. These results are also found to be consistent with the theoretical P_L values.     

Lack of Environmental Sensitivity of a Naturally Occurring Fluorescent Analog of Cholesterol

Journal of Fluorescence - Dehydroergosterol (DHE, Δ5,7,9(11),22-ergostatetraen-3β-ol) is a naturally occurring fluorescent analog of cholesterol found in yeast. Since DHE has been shown...     

Gyromagnetic ratios of excited states in 123, 125Te

The results of integral precession measurements are reported for $\text{3}\text{2}{}^{\mathrm{+}}$ and $\text{5}\text{2}{}^{\mathrm{+}}$ excited states in ^123,125Te. The measurements were made using the ion implantation perturbed angular correlation technique by recoiling the excited nuclei into polarized iron. The measured mean lifetimes and g-factors are: ${}^{123}\text{Te (440 keV,}\text{3}\text{2}{}^{\mathrm{+}}\text{) τ = 39±4 ps, g = 0.34 ± 0.06}$; $\text{(505 keV,}\text{5}\text{2}{}^{\mathrm{+}}\text{) τ = 26±3 ps, g = 0.04±0.025}$; and ${}^{125}\text{Te(443 keV,}\text{3}\text{2}{}^{\mathrm{+}}\text{) ρ = 27±3.3 ps, g = 0.39±0.06}$; $\text{(464 keV,}\text{5}\text{2}{}^{\mathrm{+}}\text{) g = 0.12±0.04}$. The results are compared with theoretical predictions.     

Evidence for particle-core coupling in the Te nucleus

The high-spin states of ¹²⁵Te have been investigated using the ¹²⁴Sn (α, 3nγ) reaction and the in-beam technique. Besides low-spin levels observed in the radioactive decay, the high-spin positive- and negative-parity bands have been established. As a possible explanation of the nature of the excited states in ¹²⁵Te the idea of the odd-neutron(hole)-core coupling is discussed.     

Evidence for the doubly magic structure of123Sn

The half lives of the levels at 4,714 keV and 4,415 keV in¹³²Sn have been determined to (20.2±0.8) ns and (4.0±0.3) ns, respectively. The half life of the 4,415 keV level in connection with the existence of aγ transition from this level into the ground state furnishes evidence for the doubly magic character of this nucleus. The transition probabilities which result from both half lives agree well with the theoretical predictions and, thereby, provide information on the structure of the positive parity states in¹³²Sn.     

Evidence for a 10+ state in132Te

A new isomeric state witht _1/2=3.9±0.3μs has been observed in the nucleus ₅₂ ¹³² Te₈₀ which has two protons more and two neutrons less than the doubly magic isobar ₅₀ ¹³² Sn₈₂. The deexcitation pattern suggests spin and parity 10⁺ for this level near 2,700 keV which is populated in fission. The energy and the half-life of the isomer can be understood with the assumption that it is the 10⁺ level based on theh ₁₁ ^2/?2 neutron hole configuration.     

Perturbed Angular Correlation Study of Naturally Occurring Zircon with very Small Impurity Concentrations

We used ¹⁸¹Ta-PAC spectroscopy to characterize the electric field gradient at Zr sites of zircon samples from the Harts Range in Australia. Zircons from this region contain very low levels of radioactive impurities. The PAC spectra between room temperature and 1100°C are axially symmetric and show little damping. The quadrupole frequency decreases linearly with increasing temperature, and the slope of the ν _Q vs. T graph increases above 900°C. This is attributed to a rearrangement of the Si–O coordination, which affects the Zr–O coordination. The spectra of all zircons show a distinct decrease of the anisotropy between 800 and 600°C. This behavior is also seen with samples that do not exhibit the change in slope in the ν _Q vs. T data. We believe that the decrease in the anisotropy is due to an aftereffect following the β-decay of ¹⁸¹Hf.     

Nonresonance Shake Mechanism in Neutrinoless Double Electron Capture

Physics of Atomic Nuclei - It is generally accepted that neutrinoless double electron capture is a resonance process. The probability for the shake followed by electron-shell ionization occurring...     

Electron density redistribution in Sn-doped Bi2Te3

X-ray photoelectron spectroscopy is used to investigate the redistribution of the density of electronic states in the valence band, and of the binding energies and chemical shifts of core levels in bismuth telluride caused by introduction of impurity tin atoms. A substantial increase in the density of electronic states below the valence-band top at energies μ≈15–30 meV has been revealed. This feature in the energy spectrum accounts for the unusual behavior of the kinetic coefficients in p-Bi₂Te₃:Sn crystals. Fiz. Tverd. Tela (St. Petersburg) 41, 1969–1972 (November 1999)     

Collective polynuclear superradiance rather thanstimulated emission of Mössbauer radiation from125m2Te and 123m2Te

Acts attributed to single-particle stimulated emission, ^125m2Te(γ,2γ)^125m1Te, had been observed previously in a Be^125m2Te sample as a variation of the line intensity at Eγ=109.27 keV and by the appearance of a line of double energy at E_2γ=218.54 keV. This effect occurred when the sample temperature, T was lowered from 300 to 4 K. In the present work, the first observation is reported of stimulated emission events in the reaction ^123m2Te(γ,2γ)^123m1Te which were registered from a Mg₃ ^123m2TeO⁶ sample when cooled in a similar fashion. It is shown here that the mechanism of these experimentally observed events is polynuclear superradiance rather than a single-particle stimulated emission of Mössbauer radiation as earlier suggested.     

Nuclear field theory and highly forbidden nuclear decays: the case of 123Te

In this paper we apply Nuclear Field Theory techniques to describe the ¹²³Te K-electron capture, whose half-life is reported to be the longest one ever measured in a single decay. The theoretical half-life we obtain varies in the range (6.0 × 10¹⁹ – 8.9 × 10¹⁹)yr, which overestimates by a factor 3–4 the experimental one.     

Tensor Interaction Effects on Stellar Electron Capture and Beta-Decay Rates

Physics of Atomic Nuclei - The Gamow–Teller strength functions as well as electron capture and $$beta$$ decay rates for $${}^{56,78}$$ Ni in hot stellar environment are calculated within a...