以近紫外光光解二碘甲烷之光譜研究; the photolysis reaction of diiodomethane at different near-ultraviolet wavelengths

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/43727

Title:	以近紫外光光解二碘甲烷之光譜研究;the photolysis reaction of diiodomethane at different near-ultraviolet wavelengths
Authors:	劉振男;Chen-Nan Liu
Contributors:	化學研究所
Keywords:	二碘甲烷;光解;diiodomethane;photolysis
Date:	2010-07-21
Issue Date:	2010-12-08 14:17:23 (UTC+8)
Publisher:	國立中央大學
Abstract:	本論文研究主要是以近紫外光光源於流動式樣品槽中光解二碘甲烷 (CH2I2) 取得放光光譜，並且搭配利用染料雷射激發物種取得的雷射誘導螢光分光光譜，從所取得的光譜中得知光解後產生的物種，在放射光譜中目前我們知道光解後產生的物種包含 CH (A2Δ)、CH (B2Σ-)、CH (C2Σ+)、C2 (d3Πg) 以及激發態碘原子，還包含一些尚未釐清的譜帶；在螢光分光光譜中我們觀測到 I2 的訊號。經實驗證實 C2 (d3Πg) 以及I2 皆為碰撞產物。而光解可能產生的中間產物如亞甲基分子 CH2 或 CHI 目前都尚未觀測到。從不同雷射功率與訊號強度關係的實驗 (power dependence)，我們可以知道 CH (A2Δ)、CH (B2Σ-) 以及 CH (C2Σ+) 皆為三個光子的產物，激發態碘原子可能為兩個光子以上的產物。最後我們還利用不同光解波長 (266 nm、280 nm 以及 330 nm)，藉由不同的波長調整所提供的光解能量，進一步的確立精確的反應能量圖。有趣地，我們發現在不同近紫外光 (260 nm 及 280 nm)光解二碘甲烷產生的 CH (A2Δ) 有能量分布不同的情形。 We studied the photolysis reaction of diiodomethane (CH2I2) at different near-ultraviolet wavelengths (266 nm, 280 nm and 330 nm) by using nascent emission spectroscopy and laser-induced dispersed fluorescence spectroscopy in a slow flow system. In the nascent emission spectrum, excited species including CH (A2Δ, B2Σ-, and C2Σ+), C2 (d3Πg), atomic iodine, and some unknown bands were found, while in the laser-induced dispersed fluorescence spectrum molecular iodine (I2) was discovered. The possible reaction intermediates such as CHI or CH2 cannot be found in nascent emission or laser-induced dispersed fluorescence spectra. Other experiments such as power dependence, concentration dependence and delay time measurements were conducted to verify the multiphoton photolysis mechanism. Based on the results, I2 and C2 are formed by the collisions of photolysis products.
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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