36 research outputs found
Coupled channel description of 16O+142,144,146Nd scattering around the Coulomb barrier using a complex microscopic potential
Angular distributions of elastic scattering and inelastic scattering from 2+ 1 state are measured for 16O+142,144,146Nd systems at several energies in the vicinity of the Coulomb barrier. The angular distributions are systematically analyzed in coupled channel framework. Renormalized double folded real optical and coupling potentials with DDM3Y interaction have been used in the calculation. Relevant nuclear densities needed to generate the potentials are derived from shell model wavefunctions. A truncated shell model calculation has been performed and the calculated energy levels are compared with the experimental ones. To simulate the absorption, a 'hybrid' approach is adopted. The contribution to the imaginary potential of couplings to the inelastic channels, other than the 2+ 1 target excitation channel, is calculated in the Feshbach formalism. This calculated imaginary potential along with a short ranged volume Woods-Saxon potential to simulate the absorption in fusion channel reproduces the angular distributions for 16O+146Nd quite well. But for 16O+142,144Nd systems additional surface absorption is found to be necessary to fit the angular distribution data. The variations of this additional absorption term with incident energy and the mass of the target are explored. Ă© 2003 Elsevier Science B.V. All rights reserved
Evidence for particle-hole excitations in the triaxial strongly-deformed well of ^{163}Tm
Two interacting, strongly-deformed triaxial (TSD) bands have been identified
in the Z = 69 nucleus ^{163}Tm. This is the first time that interacting TSD
bands have been observed in an element other than the Z = 71 Lu nuclei, where
wobbling bands have been previously identified. The observed TSD bands in
^{163}Tm appear to be associated with particle-hole excitations, rather than
wobbling. Tilted-Axis Cranking (TAC) calculations reproduce all experimental
observables of these bands reasonably well and also provide an explanation for
the presence of wobbling bands in the Lu nuclei, and their absence in the Tm
isotopes.Comment: 13 pages, 7 figure
Investigation of antimagnetic rotation in 100Pd
High spin states have been studied in the nucleus 100Pd with the aim of investigating the novel phenomenon of "antimagnetic rotation." A cascade of four "rotational-band-like" transitions is proposed as corresponding to antimagnetic rotation, based on the observed spectroscopic properties and a comparison with calculations in the configuration-dependent cranked Nilsson-Strutinsky formalism
Level structures of 96,97,98Ru at high angular momentum
The high-spin level structures of 96,97,98Ru (Z544) have been investigated using the 65Cu(36S, pxn)96,97,98Ru (x54,3,2) reactions. About 130 new transitions have been observed and unambiguously placed in the decay schemes of these nuclei. The level schemes have been extended up to spin J'22â 34\, and excitation energies Ex'20224 MeV. Spherical shell model calculations have been performed and theoretical level energies compared with experimental values. Calculations using 88Sr as the core give a reasonable agreement for the observed energy levels up to J16\), possibly manifesting vibrational behavior
Nuclear structure of 94,95Mo at high spins
The high-spin level structures of 94,95Mo (N552,53) have been investigated via the 65Cu(36S, a p2n)94Mo and 65Cu(36S, a pn)95Mo reactions at 142 MeV. The level schemes have been extended up to spin J'19\ and excitation energies Ex'12 MeV. Spherical shell-model calculations have been performed and compared with the experimental energy levels. The level structure of 94Mo exhibits a single-particle nature and the higher-angular-momentum states are dominated by the excitation of a g9/2 neutron across the N550 shell gap. The level sequences observed in 95Mo have been interpreted on the basis of the spherical shell model and weak coupling of a d5/2 or a g7/2 neutron to the 94Mo core
High-spin states in 97,98Rh
High-spin states in 97,98Rh (Z545) were populated via the 65Cu( 36S,xn)97,98Rh (x54,3) fusion-evaporation reactions. More than 40 additional transitions have been identified and placed in the decay schemes of these nuclei. The level scheme of 97Rh has been extended up to tentative spins of Jp 539/21,37/22, and the placement of some of the previously known transitions has been revised. The level structure of 97Rh indicates a single-particle nature and the observed levels are reproduced well by spherical shell-model calculations. The level scheme of 98Rh has been extended up to spins J;20\ and up to an excitation energy of ;10 MeV. The low-spin structure of 98Rh (J<10\), appears to indicate also a singleparticle structure, as supported by the stretched coupling scheme @ 97Rh(J8)^n (d5/2)598Rh (J)#
Level structure of 94,95,96Tc at high spins and shell-model calculations
High-spin states in the 94,95,96Tc (N = 51, 52, and 53) nuclei have been investigated using the 65Cu+H36S reaction at a beam energy of 142 MeV. More than 60 new transitions have been identified and placed in their level schemes, which now extend up to spin J â 22â and excitation energies Ex â 12 MeV. Spherical shell-model calculations have been performed using different model spaces. A restricted model space, using 88Sr as the core and the Ï(p 1/2,g9/2) Îœ(d5/2,s1/2) valence orbitals, reproduces the experimental excitation energies up to J â 14â. The higher-angular-momentum states are dominated by the excitation of a g9/2 neutron across the N = 50 magic core, as indicated by large-basis shell model calculations
Tidal waves in Pd102: A rotating condensate of multiple d bosons
Low-lying collective excitations in even-even vibrational and transitional nuclei may be described semiclassically as quadrupole running waves on the surface of the nucleus ("tidal waves"), and the observed vibrational-rotational behavior can be thought of as resulting from a rotating condensate of interacting d bosons. These concepts have been investigated by measuring lifetimes of the levels in the yrast band of the Pd102 nucleus with the Doppler shift attenuation method. The extracted B(E2) reduced transition probabilities for the yrast band display a monotonic increase with spin, in agreement with the interpretation based on rotation-induced condensation of aligned d bosons
Lifetime measurements of triaxial strongly deformed bands in Tm163
With the Doppler Shift Attenuation Method, quadrupole transition moments Qt were determined for the two recently proposed triaxial strongly deformed (TSD) bands in Tm163. The measured Qt values indicate that the deformation of these bands is larger than that of the yrast signature partners. However, the measured values are smaller than those predicted by theory. This observation appears to be valid for TSD bands in several nuclei of the region
Electromagnetic transition rates in high-spin bands in Nd136
Lifetimes have been measured for transitions in the two multiquasiparticle rotational bands in the nucleus Nd136. The extracted transition probabilities are compared with results of tilted-axis cranking and random-phase approximation calculations. The bands are identified as being built on two distinct quasiparticle configurations, with very different associated transition rates. These findings are contrary to an earlier suggestion that the bands form a chiral-band pair in this even-even nucleus