Wiedeking M, Tabor SL, Pavan J, Volya A, Aguilar AL, Calderin IJ, Campbell DB, Cluff WT, Diffenderfer E, Fridmann J, Hoffman CR, Kemper KW, Lee S, Riley MA, Roeder BT, Teal C, Tripathi V, Wiedenhöver I. p-sd Shell gap reduction in neutron-rich systems and cross-shell excitations in 20 O.
PHYSICAL REVIEW LETTERS 2005;
94:132501. [PMID:
15903988 DOI:
10.1103/physrevlett.94.132501]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Indexed: 05/02/2023]
Abstract
Excited states in 20O were populated in the reaction 10Be(14C,alpha) at Florida State University (FSU). Charged particles were detected with a particle telescope consisting of 4 annularly segmented Si surface barrier detectors and gamma radiation was detected with the FSU gamma detector array. Five new states were observed below 6 MeV from the alpha-gamma and alpha-gamma-gamma coincidence data. Shell model calculations suggest that most of the newly observed states are core-excited 1p-1h excitations across the N=Z=8 shell gap. Comparisons between experimental data and calculations for the neutron-rich O and F isotopes imply a steady reduction of the p-sd shell gap as neutrons are added.
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