Gamma decay of high spin states in /sup 25/Mg above 6. 1 MeV

Journal Article · Sat Oct 01 04:00:00 EDT 1988 · Phys. Rev. C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.38.1698· OSTI ID:7064474

Headly, D M; Sheline, R K; Tabor, S L; Huettmeier, U J; Gross, C J; Moore, E F; Wildenthal, B H; Weller, H R; Whitton, R M; Ragnarsson, I; others, and

New high spin states in /sup 25/Mg (up to 13.3 MeV in excitation) have been located using the /sup 12/C(/sup 14/N,p..gamma..)/sup 25/Mg reaction at a laboratory beam energy of 23.5 MeV. Gamma decay from 28 neutron unbound levels has been observed (24 of which are reported here for the first time) up to 7 MeV above the neutron drip line. Tentative identification of the yrast line up to (17/2/sup +/ has been made, along with an extension of the ground-state rotational band up to (15/2/sup +/ and the location of several other states with J/sup ..pi../ = (11/2/sup +/ and (15/2/sup +/. Extensive comparison with the s-d shell model and the cranked Nilsson-Strutinsky model has been made for the states in /sup 25/Mg. Very good agreement is observed between the shell model and experimental level energies and ..gamma..-decay branches. Potential energy surfaces for J/sup ..pi../ = (11/2/sup +/, (13/2/sup +/, and (17/2/sup +/ in the cranked Nilsson-Strutinsky model show a noncollective oblate local minimum at (epsilon/sub 2/,..gamma..) = (0.34,60/sup 0/) for (11/2/sup +/ and prolate configurations at (0.2,-120/sup 0/) for (13/2/sup +/ and (17/2/sup +/. These states compete with the collective ground-state band members at ..gamma..approx. =0/sup 0/ and become yrast for (17/2/sup +/. The stabilization of these prolate aligned states relative to more deformed, collective states of the same spin results from shell effects at high spin in the cranking model, and provides a description of the configuration in the yrast 8/sup +/; (11/2/sup +/, (13/2/sup +/, and (17/2/sup +/; and 4/sup +/ states in /sup 24/Mg, /sup 25/Mg, and /sup 26/Mg, respectively.

• Research Organization: Department of Chemistry, Florida State University, Tallahassee, Florida 32306
• OSTI ID: 7064474
• Journal Information: Phys. Rev. C; (United States), Journal Name: Phys. Rev. C; (United States) Vol. 38:4; ISSN PRVCA
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALINE EARTH ISOTOPES
ANGULAR MOMENTUM
BARYONS
CARBON 12 TARGET
CHARGED-PARTICLE REACTIONS
COINCIDENCE SPECTROMETRY
COMPOUND-NUCLEUS REACTIONS
CRANKING MODEL
CROSS SECTIONS
DEFORMED NUCLEI
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXCITATION FUNCTIONS
EXCITED STATES
FERMIONS
FUNCTIONS
GAMMA RADIATION
HADRONS
HEAVY ION REACTIONS
HIGH SPIN STATES
IONIZING RADIATIONS
ISOTOPES
LIGHT NUCLEI
MAGNESIUM 24
MAGNESIUM 25
MAGNESIUM 26
MAGNESIUM ISOTOPES
MATHEMATICAL MODELS
MEV RANGE
MEV RANGE 10-100
NITROGEN 14 REACTIONS
NUCLEAR MODELS
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
PARITY
PARTICLE PROPERTIES
PROTONS
RADIATIONS
ROTATIONAL STATES
SHELL MODELS
SPIN
STABLE ISOTOPES
TARGETS
YRAST STATES