Deformation dependence of magnetic moments in the odd transitional nuclei117–125Te

The magnetic moments of the 5/2 ₁ ⁺ state in¹¹⁷Te at 274.4 keV and of the 7/2 ₁ ⁺ state in¹²¹Te at 443.1 keV have been determined asμ _exp(5/2⁺)=?0.75(5)n.m. andμ _exp(7/2⁺)=+0.63(7) n.m., respectively, using the TDPAD method and the reactions^115,119Sn(α,2n)^117,121Te. An evaluation method is described which provides, in case of the normalized time differential patternR(t) exhibits less than half of an oscillation period, a unique value of the Larmor frequency. The comparison of the measured magnetic moments with Nilsson-, soft rotor Coriolis- as well as core-particle coupling calculations gives valuable hints on the shape dependence of magnetic moments and, consequently, on the deformation of different states in the odd transitional nuclei^117–125Te. In the light of the core-particle coupling model the positive parity states of¹¹⁷Te and¹²¹Te are interpreted as the members ofΔJ=1 andΔJ=2 bands built on thes _1/2,d _3/2,d _5/2 and g_7/2 single-particle states, respectively.     

Shell effects in the evolution of the mass asymmetry in heavy-ion collisions leading to composite systems withZ=108

Fragment mass distributions are presented obtained in the heavy-ion reactions²²Ne+²⁴⁹Cf,³²S+²³⁸U,⁴⁰Ar+²³²Th and⁵⁶Fe+²⁰⁸Pb leading to composite systems with equal nuclear charge numberZ=108. The experiments were performed at the heavy-ion cyclotron U 300 of the Laboratory of Nuclear Reactions in Dubna. The spectrometer DEMAS was used to measure the time-of-flight values and the laboratory angles of the correlated fragments. The shape of the mass distributions strongly depends on the initial mass asymmetry. When decreasing the bombarding energy down to values near the Coulomb barrier, the mass distributions obtained in the reactions³²S+²³⁸U and⁴⁰Ar+²³²Th exhibit relative maxima ofM≈205 interpreted to be due to stabilizing effects of nuclear shells during the fragmentation process.     

The magnetic moment of the 10+ isomer in140Ce and temperature dependence of the paramagnetism for Ce ions in BaO

The g-factor of the first 10⁺ isomer in¹⁴⁰Ce was determined by the time differential perturbed angular distribution method. The result is g(10⁺) = +1.03(4). The paramagnetism of Ce ions in BaO was studied in the temperature region 300 – 850 K.     

Quasimolecular K X-ray excitation by bombardment of Ge atoms with Ge ions

By bombardment of Ge targets with ⁷⁴₃₂Ge⁵⁺ of 81 MeV, a continuous X-ray intensity distribution has been obtained, which ranges up to the K X-ray energies of ₆₄Gd. The shape of the spectra, corrected for the detector efficiency, confirms the assumption that this continuum is caused by K X-rays of Z = 64 quasimolecules, which are transiently formed during the adiabatic heavy-ion collision. The yield of quasimolecular radiation was determined to be about 4 x 10⁻⁵ X-rays per beam K-vacancy.     

On the evolution of the mass asymmetry in damped heavy-ion collisions

TotaT kinetic energy vs. fragment mass distributions have been measured in the reactions of⁶⁴Zn projectiles with¹¹⁴Sn,^natAg and¹³⁹La nuclei at incidence energies of 20–50% above the Coulomb barrier. Conclusions are drawn on the possible influence of nuclear structure effects on the energy dissipation and the mass drift behaviour of the present collision systems.     

Genomics of selected human odorant receptors

Single nucleotide polymorphisms (SNPs) in odorant receptor genes may influence the protein sequence and consequently also the function of the receptors. An analysis of the HapMap data for human OR3A1 was performed and provided evidence that genetic differences subject to ancestry and gender can be recognized. A genomic comparison of individuals shows the diversity of odorant receptor genes and therefore potentially the variety of the sense of smell. At this time, two complete human genomes are available in public domain, which we used for this purpose.     

Genomics of selected human odorant receptors

Single nucleotide polymorphisms (SNPs) in odorant receptor genes may influence the protein sequence and consequently also the function of the receptors. An analysis of the HapMap data for human OR3A1 was performed and provided evidence that genetic differences subject to ancestry and gender can be recognized. A genomic comparison of individuals shows the diversity of odorant receptor genes and therefore potentially the variety of the sense of smell. At this time, two complete human genomes are available in public domain, which we used for this purpose. Correspondence: Anton Beyer, Institute of Theoretical Chemistry, University of Vienna, A-1090 Vienna, Austria.     

In-beam investigation of ternary fission

Nuclear fission accompanied by long-range alpha particles has been investigated. Fission was induced by irradiating a natural uranium target with 13.5 MeV deuterons. The alpha energy and angular distributions are similar to those observed in spontaneous or thermal neutron induced fission. The correlation angle between alpha particles and light fission fragments has a most probable value of \(\bar \vartheta _{l f - \alpha } = 82.1^\circ \pm 0.9^\circ \) and a dispersion (FWHM) of Δ?=18.4°±1.2°. The mean value and dispersion of the energy distribution are \(\bar {\rm E}_\alpha = 14.8 \pm 1.0 MeV\) and ΔE=9.1±1.2 MeV (FWHM), respectively. The peak-to-valley ratio of the ternary fission fragment mass distribution is found to increase with increasing alpha energy. For near-symmetric mass division, a strong broadening of the angular distribution is observed. The results are discussed in the frame of a multichannel-fission model.     

Structure of high-spin states in 143Pm

High-spin states of ¹⁴³Pm have been studied in the reactions ¹⁴¹Pr(α, 2n)¹⁴³Pm and ¹⁴³Nd(d, 2n)¹⁴³Pm by means of in-beam spectroscopy. The level scheme, spin and parity assignments are based on results obtained from singles γ-ray spectra, conversion electron spectra, prompt and delayed γ-γ coincidences, γ-ray angular distribution and linear polarization measurements. Positive- and negative-parity states with energies up to 4580 keV and spins up to $\text{25}\text{2}$ have been established including 22 new levels. For two nanosecond isomeric states the nuclear spin precession in an external magnetic field was observed providing the following g-factors:

$\text{g(}\text{11?}\text{2}\text{, 959.7 keV)=1.14(9), g(}\text{15+}\text{2}\text{, 1898.3 keV)=1.00(7).}$

The experimental results are well understood by calculations which have been performed in the framework of the shell model (for positive-parity states of 11 valence protons above a Z = 50, N = 82 core) and of the cluster-vibration model (for 3 holes in a Z = 64, N = 82 core). In the case of positive-parity states no evidence for particle-core coupling could be found, while the negative-parity states could qualitatively be understood within the particle-core coupling picture.