E1 and E2 strength in /sup 32/S and /sup 34/S observed in. cap alpha. -capture reactions

Journal Article · Sun Jul 01 00:00:00 EDT 1979 · Phys. Rev., C; (United States)

DOI:https://doi.org/10.1103/PhysRevC.20.5· OSTI ID:6212236

Kuhlmann, E; Calarco, J R; Cheng, V K.C.; Mavis, D G; Hall, J R; Hanna, S S

Excitation functions and angular distributions of the reactions /sup 28,30/Si(..cap alpha..,..gamma../sub 0/) were used to study the distribution of E2 strength in the energy regions 11--21 MeV of /sup 32,34/Si, as well as to probe the importance of isospin in the decay of the E1 giant resonance in these nuclei. It was found that the E2 strength in the (..gamma..,..cap alpha../sub 0/) channel is widely distributed and accounts for about 12% of the energy weighted isoscalar sum rule in each nucleus. Together with the E2 strength observed in lower resonances, about 45% of the sum rule is accounted for in /sup 32/S and 34% in /sup 34/S, where the measurements on the lower resonances are incomplete. The spreading of the E2 strength can be attributed to the mixing of np-nh configurations into the basic 1p-1h excitations of the E2 resonance, and the large E2 strength is attributed to the presence of a direct or semidirect component in the (..gamma..,..cap alpha../sub 0/) process. A comparison of the E1 strengths in the (..gamma..,..cap alpha../sub 0/) channel of the giant dipole resonances in /sup 32,34/S indicates that isospin conservation is important in these reactions. The relative weakness of the E1 (..gamma..,..cap alpha../sub 0/) strength in /sup 34/S compared to the E2 strength is attributed to the relative purity of the 1p-1h character of the E1 resonance as compared to that of the E2 resonance.

• Research Organization: Department of Physics, Stanford University, Stanford, California 94305
• OSTI ID: 6212236
• Journal Information: Phys. Rev., C; (United States), Vol. 20:1
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA REACTIONS
CAPTURE
SILICON 28 TARGET
SILICON 30 TARGET
SULFUR 32
E1-TRANSITIONS
E2-TRANSITIONS
SULFUR 34
ANGULAR DISTRIBUTION
GAMMA SPECTRA
GIANT RESONANCE
ISOSPIN
MEV RANGE 01-10
MEV RANGE 10-100
SUM RULES
TOTAL CROSS SECTIONS
CHARGED-PARTICLE REACTIONS
CROSS SECTIONS
DISTRIBUTION
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EVEN-EVEN NUCLEI
ISOTOPES
LIGHT NUCLEI
MEV RANGE
MULTIPOLE TRANSITIONS
NUCLEAR REACTIONS
NUCLEI
PARTICLE PROPERTIES
RESONANCE
SPECTRA
STABLE ISOTOPES
SULFUR ISOTOPES
TARGETS
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