Experimental and theoretical studies of the ScI, YI, Hg2, and XeI diatomic molecules

Spectroscopy;Diatomic molecules;Laser

Chen, Wenting

关键词: Spectroscopy;    Diatomic molecules;    Laser;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/99308/CHEN-DISSERTATION-2017.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Experimental and theoretical spectroscopic studies of the scandium monoiodide (ScI), yttrium monoiodide (YI), Hg2, and xenon monoiodide (XeI) diatomic molecules have been conducted. Spectra of the ScI molecule from 300 nm to 1000 nm with photoexcitation by a krypton fluorine (KrF) excimer laser at 248 nm are described. At least five new electronic and vibrational transitions of ScI were observed and analyzed. Emission spectra of YI spanning the 250 - 940 nm spectral region were also generated by the photodissociation of yttrium tri-iodide by photoexcitation of the vapor at 248 nm (KrF laser). At least five new vibrational transitions of YI were observed and analyzed. By photoexciting Hg vapor at 248 nm, a new emission band from Hg3, peaking at ∼ 380 nm, has been observed. With 266 nm optical pumping, the decay rates for the 335 nm and 485 nm emission bands of Hg2 and Hg3 at different Hg number densities were measured with improved accuracy and fitted to a new rate equation model to glean the two-body and three-body formation dynamics. The implementation of a pump-probe experimental approach showed a clear time delay between the depletion of Hg2 and Hg3 populations. The experimental photoassociative excitation spectrum of the B - X transition of XeI has also been simulated quantum mechanically. The simulated photoassociation spectrum reproduces all significant spectral details of the experimental spectrum. A new detailed potential model of the XeI ground state and a novel internuclear separation (R) segment-by-segment spectral simulation technique have been applied. The spectroscopic constants obtained are unique but consistent with previous results. Vibrational-rotational coupling in the B and X states of XeI molecules has also been verified by the improved match of the simulated spectrum with experiment.