Thesis (PhD (Physics))-University of Stellenbosch, 2009. / ENGLISH ABSTRACT: A binary cluster model is used to investigate the properties of the ground state band of 212Po,
modelled as a 208Pb-alpha core-cluster system. The results obtained using a microscopic corecluster
potential are compared to those obtained with a purely phenomenological potential. The
two potentials were found to exhibit similar surface behaviour and thus give similar predictions
for the ground state alpha decay half-life. They however generate very different energy spectra,
with the results from the phenomenological potential clearly superior. We optimize the
phenomenological potential parameters, and propose an additional short range interaction to
improve the underbinding generally found for the J¼ = 0+ ground state. We then investigate
two possible scenarios for generating the negative parity states in 212Po. We find that both are
necessary in order to produce low-lying negative parity states which are able to decay via electric
dipole transitions to the positive parity states of the ground state band. Finally we present a
novel calculation of the properties of the low-lying positive and negative parity states of 218Rn
described as a doubly closed 208Pb core plus a 10Be cluster. / AFRIKAANSE OPSOMMING: ’n Binêre bondel model word gebruik om die eienskappe van die grondtoestands energie band
van 212Po, te modeleer as ’n 208Pb-alpha kern-bondel sisteem te ondersoek. Die resultate verkry
vanaf ’n mikroskopiese kern-bondel potentiaal word vergelyk met die wat verkry is met ’n suiwer
fenomenologiese potentiaal. Die twee potentiale is verkry om dieselfde oppervlakte toestande
voor te stel en gee sodoende dieselfde voorspellings vir die grondtoestand alpha verval halfleeftyd.
Alhoewel dit baie verskillende energie spektra genereer, toon die resultate van die fenomenologiese
potentiaal dat dit duidelik beter is. Ons optimiseer hierdie fenomenologiese parameters en stel
’n addisionele kort ry-afstands interaksie voor om die algemene ondergebondenheid wat oor die
algemeen by die J¼ = 0+ grondtoestand voorkom, te verbeter. Ons ondersoek ook hierdie
twee moontlike scenarios om die negatiewe pariteitstoestande in 212Po te genereer. Ons vind
dat beide scenarios noodsaaklik is om laagliggende pariteitstoestande te produseer, sodat verval
deur elektriese dipool oorgange na die positiewe pariteitstoestande van die grondtoestandsband
moontlik is. Laagliggende positiewe en negatiewe pariteitstoestande, van die 218Rn wat beskryf
word as ’n dubbelgeslote 208Pb kern en ’n 10Be bondel.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/1299 |
| Date | 12 1900 |
| Creators | Ibrahim, Taofiq Toyin |
| Contributors | Wyngaardt, S. M., Perez, S. M., University of Stellenbosch. Faculty of Science. Dept. of Physics. |
| Publisher | Stellenbosch : University of Stellenbosch |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | University of Stellenbosch |
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