Thesis defence in the University of Oulu

Doctoral Candidate

Master of Science Juho Keskinen

Faculty and research unit

University of Oulu Graduate School, Faculty of Science, Nano and Molecular Systems Research Unit

Field of study

Physics

Date and time of the thesis defence

13.12.2019 12:00

Place of the thesis defence

Linnanmaa, auditorium L2

Topic of the dissertation

Interpretation and relativistic simulation of selected electronic transitions: Decays of M-shell hole states in atomic Cr, Br and Rb

Opponent

Adjunct Professor Rami Sankari, Tampere University

Custos

Adjunct Professor Saana-Maija Huttula, University of Oulu

Interpretation and relativistic simulation of selected electronic transitions in atomic chromium, bromine and rubidium

Information about the electronic structure of single atoms, that is, the way electrons are organized around atomic nuclei forming a so-called electron cloud, helps to understand the small-scale characteristics of compounds and materials consisting of these atoms. This information might be needed in the future, for example, in material sciences and when developing ever smaller components to be utilized in the field of information technology.

In this thesis the electronic structures and characteristics of the electron clouds of atomic chromium, rubidium and bromine have been studied. The results of the studies show the versatile nature of experiments based on a magnetic bottle set-up even by themselves or combined with traditional methods. In addition, this thesis is a good example of careful and comprehensive theoretical modeling enabling a detailed interpretation of the results.

In this thesis the characteristics and structures of electron clouds have been studied by removing an electron from the target atom and then following the electronic decay and transitions processes originating from this event. The results have been interpreted with computations based on theoretical models.

Characteristics of atomic chromium have been investigated using traditional electron spectroscopic methods, whereas those of atomic rubidium have been studied using more modern methods based on magnetic bottle enabling the simultaneous detection of multiple subsequent decay processes. The study of atomic bromine combines both methods and in addition, the results have been compared to other atoms with the same electronic structure. All the studied atoms have been modeled theoretically with relativistic quantum mechanical methods.

The results of the chromium study are an improvement over the previous studies and on top of that suggest identifying one of the detected transitions differently than before. Studies on the selected transitions in rubidium help to understand the structure of its electron cloud better. For the first time it is also possible to unambiguously identify internal transitions happening simultaneously with the observed decay within the electron cloud. The study on bromine atoms makes it possible to identify its electronic structure in more detail than before. In addition, the decay process features a single very fast transition, which would have gone unnoticed with more traditional methods.

 

Dissertation

Last updated: 11.12.2019