Calculations of K-Shell Fluorescence Yields and Photoabsorption Cross Sections for Carbon Ions at the K-Edge
Date of Award
Doctor of Philosophy
Dr. Thomas W. Gorczyca
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 2 nd -row ions. A secondary project was undertaken in order to treat theoretically the K-shell X-ray absorption processes in carbon ions. These calculated fluorescence yields of 2nd -row ions and theX-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 (MCBP), whereas for computing K-shell photoabsorption cross sections, we used the Belfast R-matrix 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 ofmany higher-order effects, such as configuration interaction, relativistic corrections, and Auger-broadening, are crucial for producing, quantitatively and sometimes qualitatively, accurate atomic data.
Hasoglu, Muhammet Fatih, "Calculations of K-Shell Fluorescence Yields and Photoabsorption Cross Sections for Carbon Ions at the K-Edge" (2008). Dissertations. 776.