Dissertation Defenses

Doctoral Dissertation Announcement

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Candidate: Muhammet Fatih Hasoglu

Degree of: Doctor of Philosophy

Department: Physics

Title: Calculations of K-Shell Fluorescence Yields and Photo-absorption Cross Sections for Carbon Ions at the K-Edge

Committee:
Dr. Thomas W. Gorczyca, Chair
Dr. Dean W. Halderson
Dr. Nora Berrah
Dr. Kirk T. Korista
Dr. Steven T. Manson

Date: Friday, November 7, 2008 4:00 p.m. - 6:00 p.m.
2202 Everett Tower

Abstract:
The advent of new space missions providing high-precision observations has engendered the need for reliable and precise K-shell atomic data in order to interpret these X-ray spectra. In response to this need, we focused on the calculation of K-shell fluorescence yields for 2nd row ions. A secondary project was undertaken to theoretically treat the K-shell X-ray absorption processes in carbon ions. These calculated fluorescence yields of 2nd row ions and the X-ray photoabsorption cross sections of carbon are astrophysically important in determining 1) charge-changing probabilities, such as Auger vs. radiative decay, and 2) chemical abundances of the interstellar medium (ISM).
For computing K-shell fluorescence yields, we used the atomic structure and collision computer package AUTOSTRUCTURE within a multi-configuration Breit-Pauli method; whereas for computing K-shell photoabsorption cross sections, we used the Belfast Rmatrix computer package. These theoretical results, when compared to available experimental and theoretical results, show good overall agreement. Of particular importance, we find that the inclusion of many higher-order effects, such as configuration interaction, relativistic corrections, and Auger-broadening, are crucial for producing, quantitatively and sometimes qualitatively, accurate atomic data.