title: p-sd Shell gap reduction in neutron-rich systems and cross-shell excitations in 20 O.
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.
authors.affiliation: Florida State University, Tallahassee, Florida 32306, USA.
authors.forename: M
authors.initials: M
authors.lastname: Wiedeking
authors.forename: S L
authors.initials: SL
authors.lastname: Tabor
authors.forename: J
authors.initials: J
authors.lastname: Pavan
authors.forename: A
authors.initials: A
authors.lastname: Volya
authors.forename: A L
authors.initials: AL
authors.lastname: Aguilar
authors.forename: I J
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authors.lastname: Calderin
authors.forename: D B
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authors.lastname: Campbell
authors.forename: W T
authors.initials: WT
authors.lastname: Cluff
authors.forename: E
authors.initials: E
authors.lastname: Diffenderfer
authors.forename: J
authors.initials: J
authors.lastname: Fridmann
authors.forename: C R
authors.initials: CR
authors.lastname: Hoffman
authors.forename: K W
authors.initials: KW
authors.lastname: Kemper
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: M A
authors.initials: MA
authors.lastname: Riley
authors.forename: B T
authors.initials: BT
authors.lastname: Roeder
authors.forename: C
authors.initials: C
authors.lastname: Teal
authors.forename: V
authors.initials: V
authors.lastname: Tripathi
authors.forename: I
authors.initials: I
authors.lastname: Wiedenhöver