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

Chen, Wenting

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https://hdl.handle.net/2142/99308 Copy

Description

Title

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

Author(s)

Chen, Wenting

Issue Date

2017-10-24

Director of Research (if dissertation) or Advisor (if thesis)

Eden, James G.

Doctoral Committee Chair(s)

Eden, James G.

Committee Member(s)

• McCall, Benjamin J.
• Toussaint, Kimani C.
• Lee, Minjoo L.

Department of Study

Electrical & Computer Eng

Discipline

Electrical & Computer Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Spectroscopy
• Diatomic molecules
• Laser

Abstract

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.

Graduation Semester

2017-12

Type of Resource

text

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http://hdl.handle.net/2142/99308

Copyright and License Information

Copyright 2017 Wenting Chen

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