Charge-independent trend of isoscalar matrix elements along the N similar to Z line

Shell model calculations have been carried Out using the m-scheme numerical code ANTOINE in order to elucidate the particular trend of the isoscalar matrix elements, M-0, for A = 4n + 2 isobaric triplets ranging from A = 18 to A = 42. The 2(1)(+) (T = 1) -> 0(1)(+) (T = 1) transition energies, reduced transition probabil ities and isoscalar matrix elements are predicted to a high degree of accuracy. The general agreement of M-0 between those from mirror pairs and those from T-Z = 0 nuclides support our shell model calculations, The predicted results tic together recent experimental data, and the trend of M-0 strength along the sd and beginning of the fp shells is interpreted in terms of the dynamic shell structure. Certain discrepancies arise at A = 18 and A = 38 isobaric triplets, which might be explained in terms of core polarization effects and the low occupancy of the orbits at the extremes of the sd shell. (c) 2005 Elsevier B.V. All rights reserved

Status of vibrational structure in Ni62

Measurements consisting of γ-ray excitation functions and angular distributions were performed using the (n,n′γ) reaction on Ni62. The excitation function data allowed us to check the consistency of the placement of transitions in the level scheme. From γ-ray angular distributions, the lifetimes of levels up to ~3.8 MeV in excitation energy were extracted with the Doppler-shift attenuation method. The experimentally deduced values of reduced transition probabilities were compared with the predictions of the quadrupole vibrator model and with large-scale shell model calculations in the fp shell configuration space. Two-phonon states were found to exist with some notable deviation from the predictions of the quadrupole vibrator model, but no evidence for the existence of three-phonon states could be established. Z=28 proton core excitations played a major role in understanding the observed structure. © 2011 American Physical Society

High-Statistics Study of the beta(+)/EC-Decay of (110)An

status: publishe

Nature of low-lying electric dipole resonance excitations in Ge 74

Isospin properties of dipole excitations in 74 Ge are investigated using the (α , α ′ γ ) reaction and compared to (γ , γ ′ ) data. The results indicate that the dipole excitations in the energy region of 6 to 9 MeV adhere to the scenario of the recently found splitting of the region of dipole excitations into two separated parts: one at low energy, being populated by both isoscalar and isovector probes, and the other at high energy, excited only by the electromagnetic probe. Relativistic quasiparticle time blocking approximation (RQTBA) calculations show a reduction in the isoscalar E1 strength with an increase in excitation energy, which is consistent with the measurement