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A Homologous Study of Lifetimes and Oscillator Strengths of Ultraviolet Transitions in Singly Ionized Lead, Tin, and Germanium
Başlık:
A Homologous Study of Lifetimes and Oscillator Strengths of Ultraviolet Transitions in Singly Ionized Lead, Tin, and Germanium
Yazar:
Negar, Heidarian, author.
ISBN:
9780438092884
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (131 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Steven Federman Committee members: Song Cheng; Richard Irving; Victor Karpov; Elmer Trabert.
Özet:
This thesis provides experimentally determined lifetimes and oscillator strengths (f-values) for radiative transitions of astrophysical interest for three elements of group iv of the periodic table in singly ionized form, namely Pb II, Sn II, and Ge II. The work is complemented by reporting the results of fully relativistic calculations for lifetimes and oscillator strengths of interest for the Sn II and Ge II structures.
The experimental values are obtained using beam-foil techniques performed with the Toledo Heavy Ion Accelerator (THIA) at the University of Toledo. The lines of interest involve transitions from nsnp 2 2D3/2,5/2 and ns2nd 2D 3/2,5/2 levels to the ground term for the three ions. The corresponding f-values are obtained from the lifetimes and compared with other available work.
The theoretical section of this thesis consists of ab-initio calculations for Sn II and Ge II using the GRASP2K package (Jonsson et al 2013, 2014) with a Multi Configuration Dirac-Hartree-Fock approach. The calculated values for these two ions are compared with our experimental results as well as other available theoretical and experimental work. The experimental and theoretical values for Pb II are compared and discussed also. Multiplet values are reported as well.
Our measured values are the first experimentally determined values in most cases and in other cases, our values confirm the previously measured lifetimes for these ions. Our theoretical calculations are among very few fully relativistic theoretical treatments for these structures, and they support our measured values while generally consistent with the most recent calculations by others. Our experimental and theoretical systematic studies of these ions show that the relativistic effects in the Pb II structure are more important than in the other two ions; while filling in the gaps in the atomic data for these ions, future studies of the interstellar neutron-capture elements can be placed on more secure grounds.
Notlar:
School code: 0232
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(687060.1) | 687060-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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