Akademik Veri Yönetim Sistemi
Tez Türü: Doktora
Tezin Yürütüldüğü Kurum: İstanbul Teknik Üniversitesi, Lisansüstü Eğitim Enstitüsü, Fizik Mühendisliği, Türkiye
Tez Danışmanı: Prof. Dr. Günay Başar
Tezin Onay Tarihi: 2025
Tezin Dili: Türkçe
Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
Desteklendiği Program: Bu tezi destekleyen bir program bulunmamaktadır
Özet:
| The fundamentals of atomic physics are based on theoretical and experimental studies throughout history. Atomic physics focuses mainly on the structure of atoms, their interactions with each other, and their interactions with photons. The interaction of photons with matter is widely used in experimental studies to understand the properties of atoms and obtain information about their energy levels and the dynamics of excited atoms. In atoms, the orbital and spin motion of the electron around the nucleus creates an internal magnetic field that interacts with the electron's magnetic moment and orients its spin. This interaction is known as the spin-orbit interaction and causes fine structure (fs) splitting of the energy levels in the atom. The interaction of electromagnetic multiple nuclear moments with the electric and magnetic field produced by spinning and orbiting electrons around the nucleus gives rise to a further splitting, namely hyperfine structure splitting (hfs) of the fine structure levels. Photons can be absorbed or emitted by their interaction with atoms. Absorption takes the atom from a lower to a higher energy level, whereas emission occurs spontaneously or is induced from a higher to a lower energy level by releasing radiation. The study of absorption or emission of light by matter is known as 'Spectroscopy'. With the development of laser technology, coherent light sources, such as lasers, have been used in spectroscopic studies due to their high intensity, extremely narrow linewidth, good focusing properties, and enhanced sensitivity in measurement techniques. The spectral line occurring from emission or absorption can be measured using laser spectroscopic methods for further analysis. The use of lasers in spectroscopic studies gave rise to different techniques such as Laser-AbsorptionSpectroscopy, Optoacoustic Spectroscopy, Optogalvanic Spectroscopy (OGS), Cavity-Ringdown Spectroscopy, Laser Induced Fluorescence (LIF) Spectroscopy, Ionization Spectroscopy and Saturation Spectroscopy. This dissertation aimed to experimentally discover new even and odd parity fine structure energy levels of atomic Holmium in the 690-830 nm wavelength range using Laser Induced Fluorescence spectroscopy (LIFS) and Optagalvanic spectroscopy (OGS) methods simultaneously. Free and excited Holmium atoms were generated in a liquid nitrogen-cooled hollow-cathode lamp. The corresponding magnetic dipole (A) and electric quadrupole (B) hyperfine structure constants were also determined. To confirm the existence and precisely determine the energy values of the new energy levels, we analyzed lines from previously recorded Fourier Transform (FT) spectra. In total, 16 new energy levels have been discovered, comprising five with even parity and 11 with odd parity. Data on the hyperfine structure of these new levels, as well as additional hyperfine structure data for three known levels of even parity obtained from existing literature, have been presented for the first time. The findings of this dissertation will be available as a resource in the National Institute of Standards and Technology (NIST) Atomic and Molecular Database. This will help establish a crucial infrastructure for other scientific pursuits, especially in the fields of astrophysics. |