Statistical spectroscopy study of alpha particle transfer strengths

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1981

OSTI ID:5983952

Countee, C R

The theory emphasizes the importance of traces of bilinear products of operators acting in a model space. Utilizing this and partitioning the model space according to group symmetries leads to an algorithm for expanding an interaction in terms of simpler operators. Detailed shell model comparison of excitation spectra, eigenstate overlaps and B(E2) transition strengths in /sup 20/Ne and /sup 22/Ne with a realistic interaction and its SU(3) trace-equivalent approximations are presented. SU(3) symmetry breaking by single-particle shell effects is also studied. Spectral distribution methods are used to develop a statistical procedure for calculating alpha particle transfer strengths that is valid in large model spaces. The theory gives the strength function as a bilinear expansion in orthogonal polynomials defined by moments of the interaction in the initial and final state model spaces. Rapid convergence is assured by the operation of the central limit theorem. The method involves partitioning the fixed J, T initial (target nucleus) and final (residual nucleus) state model spaces according to the supermultiplet symmetry. Moments of a statistical approximation to the Brown-Kuo interaction are used to estimate the eigenenergies and configuration intensities for the initial and final state subspaces. Specific predictions for the reactions /sup 18/O + ..cap alpha.. reversible /sup 22/Ne and /sup 20/Ne + ..cap alpha.. reversible /sup 24/Mg are made. The results are compared with experimental values and with predictions of other nuclear models. A unique feature of the study, unlike what has been found for E2, M1, E4 strengths, is that the density weighted strength is not dominated by the density of states factor.

• Research Organization: Louisiana State Univ., Baton Rouge (USA)
• OSTI ID: 5983952
• Country of Publication: United States
• Language: English

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73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALKALINE EARTH ISOTOPES
ALPHA REACTIONS
ALPHA-TRANSFER REACTIONS
CHARGED-PARTICLE REACTIONS
DATA
DIRECT REACTIONS
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
FOUR-NUCLEON TRANSFER REACTIONS
INFORMATION
ISOTOPES
LIGHT NUCLEI
MAGNESIUM 24
MAGNESIUM ISOTOPES
MULTI-NUCLEON TRANSFER REACTIONS
NEON 20
NEON 20 TARGET
NEON 22
NEON ISOTOPES
NUCLEAR REACTIONS
NUCLEI
NUMERICAL DATA
OXYGEN 18 TARGET
SPECTROSCOPY
STABLE ISOTOPES
TARGETS
THEORETICAL DATA
TRANSFER REACTIONS