多光子光解溴甲烷類分子產生 高激發態溴原子之研究

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71313

Title:	多光子光解溴甲烷類分子產生高激發態溴原子之研究
Authors:	林政傑;Lin,Zheng Jie
Contributors:	化學學系
Keywords:	高激發態溴原子
Date:	2016-07-25
Issue Date:	2016-10-13 12:43:02 (UTC+8)
Publisher:	國立中央大學
Abstract:	本研究於室溫下流動式樣品槽中以不同波長紫外光光解溴甲烷類分子(CBr4、CHBr3、CHBr2Cl、CH2Br2、CHBrCl2)，研究其初始放光光譜中高激發態溴原子之形成機制。本論文經由改善實驗條件取得訊號更佳之高激發態溴原子放光光譜，因此發現到許多先前未觀測到之高激發態溴原子譜線，並發現產生高激發態溴原子應為四光子過程，而非先前文獻所認為的三光子過程。並以不同波長的紫外光光解溴甲烷類分子，發現在266 nm到300 nm的區間裡，高激發態溴原子的光解波長趨勢會隨著波長的增加而遞減，而且溴化甲烷類分子的趨勢一致，但是此趨勢和碘甲烷類分子產生高激發態碘原子之光解波長趨勢並不相同。此外經由反應能量及相關光電子光譜文獻之考量，發現最有可能的四光子機制為1 + 3之過程。 ;Emission spectra following the photolysis of bromomethanes (CBr4, CHBr3, CHBr2Cl, CHBrCl2, and CH2Br2) at different ultraviolet wavelengths were recorded at ambient temperature for investigating the formation mechanisms of highly excited atomic bromine. This work improved the experimental conditions to obtain better signal-to-noise ratios in the emission spectra, and several newly observed transitions of atomic bromine were found. Power dependence and pressure dependence measurements were also conducted. The results indicate that the formation mechanism of highly excited atomic bromine is a four-photon process instead of a three-photon process reported in the previous study. For these bromomethanes, the photolysis wavelength dependences were acquired and show a similar decreasing trend from 266 nm to 300 nm. This photolysis wavelength dependence is profoundly different from that of iodomethanes. Based on the reaction enthalpies and related photoelectron spectra, the most likely mechanism for the formation of highly excited bromine is a 1+3 process.
Appears in Collections:	[Graduate Institute of Chemistry] Electronic Thesis & Dissertation

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