氮氣分子在45-100 nm之光吸收、光離子化、光解離

Photoabsorption, photoionization, and photodissociation of N2 in the wavelength region 45-100 nm

張光宇(Kuang-Yu Chang)

指導教授 ： 倪簡白

國立中央大學/理學院/化學系/碩士(2008年)

摘要

本篇論文的實驗我們使用了新竹同步輻射中心Seya，U9，以及High Flux光束線 ，使用光電倍增管測量紫外-可見光(180-650 nm)和真空紫外光(115-320nm )的螢光光譜和吸收光譜。我們這次實驗得到超高解析度的真空紫外螢光光譜，這光譜是由雷德堡態的氮氣中性分子轉變成帶一正電的激發態氮氣離子C 2Σu+ nsσg n= 4, 5態和D2Πgi nlλ態，最後再經由C-X和D-A的機制放光。實驗所得到的光譜，我們都會對照氮氣吸收光譜進行驗證比較。
在氮氣光譜的歷史中，我們第一次能夠利用同步輻射光源和multichannel plate(MCP)、position sensitive detector(PSD)，清楚地直接觀察到激發態氮氣分子c4’(0)和b(1)態產生的共振螢光，還有藉由光解碎片產生的氮原子放光。說到原子放光，同樣利用MCP偵測光分解產生的激發態氮原子(2P, 4P, 4D)產生的 98 nm 到 150 nm特定波長的原子放光。最後，我們在論文中作光譜的整理和總結並討論其產生的原因。

關鍵字

氮氣 ； 光吸收 ； 光離子化 ； 光解離

並列摘要

Our experiment is aimed to investigate, including for the nitrogen absorption and fluorescence in the 45-60 nm region, atomic emission in particular wavelengths from 46.4 to 61.7 nm, and nitrogen resonance fluorescence of c4’(0) and b(1) states.

We employed the light source at the Seya, U9 and high flux beamlines of National Synchrotron Radiation Research Center in Hsin-Chu, and measure two channels of fluorescence and one of nitrogen absorption in uv-visible (180-650 nm) and VUV (115-320nm ) by using PMTs. In 12-25 eV, the VUV fluorescence, observed clearly in higher resolution than one of P. Erman, is produced by the Codling Rydberg states, converging to C 2Σu+ nsσg state with n= 4, 5 of N2+ C-X emission and D2Πgi nlλ state with n=3 of N2+ D-A emission. All these spectra are compared with the absorption spectrum in 45-50 nm and 50-55 nm regions that we focus.

In the history of nitrogen spectra, we observed directly resonance fluorescence of c4’(0) and b(1) state and atomic emission produced by the photofragment with the combination of the multichannel plate(MCP) and position sensitive detector(PSD) at the synchrotron radiation facility. Speaking of atom emission, it is also shown on MCP in some particular wavelengths from 98 nm to 150 nm when excited nitrogen atoms (2P, 4P, 4D) are produced. Finally, we conclude the cause and find the result of the spectra in this thesis.

並列關鍵字

N2 ； Photoabsorption ； photoionization ； photodissociation

參考文獻

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