利用步進式時域解析傅氏轉換紅外光譜法研究丙酮腈之光分解反應

Photodissociation of Acetyl Cyanide Detected with Time-resolved Fourier Transform Infrared Spectroscopy

葉育穎(Yu-Ying Yeh)

指導教授 ： 林金全

國立臺灣大學/理學院/化學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.10887

摘要

本論文係以步進式時間解析-傅立葉轉換光譜儀，研究丙酮腈（CH3COCN）分子與焠熄氣體Ar於單光子308 nm能量下之光解反應。本實驗觀測光分解產物，可標定HCN (1≤v≤ 2, J≤ 24)和CO (1≤v≤ 3, J≤ 20)振動-轉動譜線。其中氬氣扮演誘使丙酮腈分子經由內轉移路徑並增加其光分解產物訊號強度。
分析光解產物時間解析之振動、轉動分布情形及內能分配，得到CO分子振動-轉動能量為18.95±6.30 kJ/mol。配合ab inito的計算，輔助反應路徑的過程解釋光分解產是經由高能基態CH3COCN發生四中心分解HCN分子，剩餘CH2CO分子具有足夠內能再進行第二次分解產生CO及CH2。

關鍵字

丙酮腈紅外光譜 ； 光分解反應 ； 轉移 ； 振轉動

並列摘要

By employing time-resolved Fourier-transform infrared emission spectroscopy, the fragments of HCN(v=1-2) and CO(v=1-3) are detected in one-photon dissociation of acetyl cyanide (CH3COCN) at 308 nm. The Ar gas is added to induce internal conversion and enhance the fragment yields.
The time-dependent high-resolution spectra of CO are analyzed to determine the corresponding ro-vibrational energy deposition 18.95±6.30 kJ/mol. With the aid of ab initio calculations, the observed fragments are proposed to dissociate on the hot ground state CH3COCN. A four-center dissociation channel is favored leading to HCN + CH3CO in which the CH3CO moeity may further undergo secondary dissociation to release CO and CH2 fragments.

並列關鍵字

acetyl cyanide ； infrared spectroscopy ； photodissociation ； internal conversion ； ro-vibration

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