Date of Award

8-7-2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

First Advisor

Steven Manson

Second Advisor

Vadym Apalkov

Third Advisor

Russel White

Fourth Advisor

Mukesh Dhamala

Fifth Advisor

Brian Thoms

Abstract

At high enough Z relativistic effects become important contributors to even the qualitative nature of atomic properties. This is likely to be true for confined atoms as well. To explore extent of relativistic effects in the photoionization of both free and confined heavy atoms, a theoretical study of the outer subshells of mercury (Z= 80), radon (Z=86), radium (Z=88), and nobelium (Z=102) have been performed using the relativistic random phase approximation (RRPA) methodology in both the free and confined cases. The effects of the C60 potential modeled by a static spherical well are reasonable in the energy region well above the C60 plasmons. In order to determine which features in the photoionization cross section are due to relativistic effects, calculations using the (nonrelativistic) random phase approximation with exchange method (RPAE) are performed for comparison. It is found that relativistic interactions shift and split the nonrelativistic thresholds very considerably, and these changes in thresholds translate into very significant alterations to the nonrelativistic cross section. Relativity also alter the wave functions, contracting the s and p orbital significantly for example. These dynamic changes have considerable effects on the relativistic cross sections.

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