Structural characteristics of metal oxide thin films grown by pulsed laser deposition [and] fluorescence excitation spectroscopy of amino radical, fluoromethylene, and chlorocarbene under jet-cooled condition and measurement of fluorescence lifetime

Haiyan Fan, Marquette University

Abstract

This present dissertation will be found useful in controlling the conditions of formation of Litharge phase of SnO and Orthorhombic phase of SnO2 , such as ablation laser fluence, wavelength, film thickness and by using metal target followed by the annealing in the air. Ga2 O 3 thin films have also been grown by PLD under vacuum or in the oxygen ambient gas. The film characteristics and the comparison between vacuum and in oxygen environment were described in detail in this dissertation. It is found that the initial component of thin films has strong correlation with the component of neutral gas phase produced in ablation. We studied the laser fluence dependencies in the 532 nm ablation of Ga2 O 3 target and the velocity distribution was described with shifted or unshifted, single or multi component Maxwell-Boltzmann distribution. In this dissertation, a total 14 pure bending bands of NH2 were scanned and the transition frequencies were fit with a linear least-squares routine to a modified Hill and Van Vleck equation. In the case of HCCl, only Ka' = 0 bending sub-bands and C-Cl stretching containing combination bands (0, ν2 ' -1, 1) and (0, ν2' -2, 2) caused by Fermi resonance were observed. Fluorescence lifetime is another important indicator for the dynamics of free radicals and carbenes. The lengthening of lifetime indicates the occurrence of perturbation while the drastically shortened lifetime stands for the nonradiative relaxation or occurrence of decomposition for small molecules. With the resolution of our laser, we can measure the lifetime for a specific rovibronic line. Fluorescence lifetimes for NH2HASH(0xfadaf6c)Ã 2A1 Σ bands (ν2 ' = 9-25) were measured and in reasonable agreement with the three dimension theoretical calculation. Lifetimes of HCF showed a strong dependence on Ka' value, which was dominated by Renner-Teller effect. The lengthening of lifetime was commonly observed for Ka' > 0 sub-bands, which indicates the occurrence of perturbation. However the lengthening of lifetime itself cannot tell what kind of perturbation is involved in the specific situation. (Abstract shortened by UMI.)

Subject Area

Chemistry

Recommended Citation

Fan, Haiyan, "Structural characteristics of metal oxide thin films grown by pulsed laser deposition [and] fluorescence excitation spectroscopy of amino radical, fluoromethylene, and chlorocarbene under jet-cooled condition and measurement of fluorescence lifetime" (2004). Dissertations (1962 - 2010) Access via Proquest Digital Dissertations. AAI3153998.
https://epublications.marquette.edu/dissertations/AAI3153998

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