Identification and decay of182Tl

A new activity with a 3s half-life at mass 182 was produced via proton spoliation reaction on thorium carbide target and mass separation. From the observation of known rays observed in¹⁸²Hg, it was assigned to the (⁺+ EC) decay of¹⁸²Tl, the spin and parity of which is very likely 7⁺.     

On lineγ-Ray emission following 30 MeV/A12C induced reactions on some medium-heavy targets

Preliminary results on residual nuclei production in 30 MeV/A¹²C interaction with medium heavy targets are presented. Gamma-ray spectroscopic techniques were used. Evidence for charge and angular momentum transfer is found.

     

Lattice dynamics of molybdenum at high pressure

We have determined the lattice dynamics of molybdenum at high pressure to 37 GPa using high-resolution inelastic x-ray scattering. Over the investigated pressure range, we find a significant decrease in the H-point phonon anomaly. We also present calculations based on density functional theory that accurately predict this pressure dependence. Based on these results, we infer that the likely explanation for the H-point anomaly in molybdenum is strong electron-phonon coupling, which decreases upon compression due to the shift of the Fermi level with respect to the relevant electronic bands.     

New exotic neutron-deficient nuclei nearN=82

Residual activities produced via³⁵Cl or³²S beams in thin¹¹²Sn and¹⁰⁶Cd targets have been studied by γ-ray and X-ray spectroscopy techniques behind a He-jet system. Mass identification of the products has been performed by coupling the He-jet to the medium current ion source of an isotope separator. Neutron-deficient nuclei with 137≦A≦144 have been identified. Decay schemes of several new isotopes as¹³⁸Eu (12s),¹⁴¹Gd (22s),¹⁴³Tb (12s and <17s),¹⁴⁴Dy (9s) and possibly¹⁴⁰Gd (11s) have been derived. New informations have also been provided for¹³⁷Sm (45s),¹³⁹Eu (24s) and¹⁴⁴Tb (5s). Data have been presented through systematics. The shapes of these nuclei and their trends versusN andZ have been analysed.     

Lattice dynamics of MgO at high pressure: theory and experiment

The longitudinal acoustic and optical phonon branches along the Gamma-X direction of MgO at 35 GPa have been determined by inelastic x-ray scattering using synchrotron radiation and a diamond-anvil cell. The experimentally observed phonon branches are in remarkable agreement with ab initio lattice dynamics results. The derived thermodynamic properties, such as the specific heat CV and the entropy S are in very good accord with values obtained from a thermodynamically assessed data set involving measured data on molar volume, heat capacity at constant pressure, bulk modulus and thermal expansion.     

The alpha decay study of223Th (T 1/2=0.6 s)

Correlations between neutrons have been studied in the 96 MeV¹⁸O +⁶⁴Ni reaction, yielding the compound nucleus⁸²Kr at 88 MeV excitation energy. The observed anticorrelation at small relative momenta evidences dominance of quantum-statistical interference between identical particles, from which it is possible to deduce an average source lifetimeτ=(1.2±0.1)·10^?20 s as an upper limit disregarding possible contributions to the correlation function from the competingnn final-state interaction. Lacking appropriate model calculations at present, it is argued that further refinements in the theoretical treatment of strong interactions in the final state are needed to enable truly quantitative conclusions from small-angle nucleon-nucleon correlations at such large timescales.     

Identification and decay of 12s 138Eu

Narrow p,γ resonances have been investigated by using inverse reactions with heavy-ion beams, e.g.¹⁵N,²⁷Al and³⁰Si. The observed line shapes of dominant Gaussian form are due to the vibrational modes of¹H bonded to heavy target atoms.     

Influence of pressure on the boson peak: stronger than elastic medium transformation

We study the changes in the low-frequency vibrational dynamics of poly(isobutylene) under pressure up to 1.4 GPa, corresponding to a density change of 20%. Combining inelastic neutron, x-ray, and Brillouin light scattering, we analyze the variations in the boson peak, transverse and longitudinal sound velocities, and the Debye level under pressure. We find that the boson peak variation under pressure cannot be explained by the elastic continuum transformation only. Surprisingly, the shape of the boson peak remains unchanged even at such high compression.     

Collective excitation of 103Ag following the (12C,p2nγ) reaction

Excited states of ¹⁰³Ag have been investigated in the ⁹⁴Mo(¹²C, p2nγ)¹⁰³Ag reaction and observed up to 6414 keV excitation energy. A perturbed band based on the 27.6 keV $\text{9}\text{2}$⁺ intrinsic state has been strongly populated up to spin $\text{27}\text{2}$⁺. In addition, two negative-parity bands with spins ranging from $\text{19}\text{2}$^? to at least $\text{29}\text{2}$^? were also observed. An interpretation of the experimental results is proposed in the framework of the axial-symmetric rotor-plus-particle model using deformed self-consistent quasi-particle states.