Microscopic description of giant resonance excitations in A [] 90 nuclei /
A microscopic description of giant resonance excitations in several A < 90 nuclei is given based on self-consistent Skyrme-Hartree-Fock-Random-Phase-Approximation calculations. An existing parametrization of the Skyrme interaction which give 230 MeV for the value of nuclear matter incompressibili...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733050301&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A microscopic description of giant resonance excitations in several A < 90 nuclei is given based on self-consistent Skyrme-Hartree-Fock-Random-Phase-Approximation calculations. An existing parametrization of the Skyrme interaction which give 230 MeV for the value of nuclear matter incompressibility coefficient is used. Nuclei of ²⁸Si, ⁴⁰Ca, ⁵⁶Ni, and ⁶⁰Ni are selected for the stated purposes. The selection is based on the availability of results of recent experimental studies performed at Texas A&M University. A theoretical description of the ground state of ²⁸Si, ⁴⁰Ca, ⁵⁶Ni, and ⁶⁰Ni nuclei within the Skyrme-Hartree-Fock method is provided. The coordinate space formulation of the RPA in terms of Green's functions is employed to obtain isovector dipole, isoscalar quadrupole, and isoscalar monopole transition strength distributions for ²⁸Si, ⁴⁰Ca, ⁵⁶Ni, and ⁶⁰Ni nuclei. Calculations are erformed with the discredited single-particle continuum. Theoretical transition strength distributions are used to find quantities of interest such as energy positions of resonance states, sum rules, average resonance energies, and transition densities. A description of 240 MeV a-particle scattering on ²⁸Si, ⁴⁰Ca, ⁵⁶Ni, and ⁶⁰Ni target nuclei is given within the Distorted Wave Born Approximation (DWBA). The folding model is used to obtain optical potentials from the Hartree-Fock round state density and a two-body density dependent Gaussian interaction. Parameters of the two-body interaction are found by fitting experimentally measured angular distributions for the case of elastic scattering. Angular distributions of analytically scattered a-particles for isoscalar quadrupole and isoscalar monopole excitations of the target nucleus are obtained using folding model DWBA and both microscopic and hydrodynamical (collective model) transition densities (found from Hartree-Fock ground state densities). Radial shape differences of microscopic and collective model transition densities and the effect of such differences on the calculated angular distributions are studied. Possible overestimation of the energy weighted sum rules in experimental analyses of giant monopole and quadrupole excitations due to collective-model-based DWBA reaction description is reported. The results are in satisfactory ailment with recent experimental data on ²⁸Si and ⁴⁰Ca nuclei. |
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| Item Description: | Vita. "Major Subject: Physics". In title symbols are used. |
| Physical Description: | x, 113 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 95-99). |