本論文研究是以近紫外光266nm為光解光源於流動式樣品槽 (flow cell)中進行碘甲烷 (CH3I)、二碘甲烷 (CH2I2)以及碘仿 (CHI3)的光解反應。而在本實驗室先前研究結果顯示光解碘化甲烷類分子在可見光區有一系列未知譜帶，並對這未知譜帶進行條件的最佳化以及利用雷射誘導螢光分光光譜 (dispersed fluorescence)分析其能階資訊。在本研究中則搭配使用高靈敏度增強式電荷偶合偵測器 (High Sensitivity Intensified Charge-Coupled Device Detector)以及光電倍增管 (PMT)來取得碘化甲烷類分子光解後的雷射誘導螢光激發光譜 (laser-induced fluorescence)以及雷射誘導螢光分光光譜。經由同位素取代實驗以及分析所觀測到的激發光譜、物種波型與放射生命期的文獻比較後可得知以266 nm光解碘化甲烷類分子後，在螢光分光光譜中所觀測到的主要為碘分子B3Π +0,u − X1Σ+g不同能階的躍遷，並且利用碘分子的能階參數對螢光分光光譜以及螢光激發光譜進行譜線位置的模擬。最後再藉由觀察碘分子、C2和未知譜帶不同壓力下的訊號強度，確認了碘分子的生成路徑與C2和未知譜帶並不相同。A series of unknown bands was found in the nascent emission spectrum following the 266 nm photolysis of iodomethanes (CH3I, CH2I2 and CHI3) in a slow flow cell, but laser-induced dispersed fluorescence (DF) spectra following excitation of these unknown bands show different vibrational structures. In this study, the laser-induced fluorescence (LIF) excitation spectrum and improved DF spectra were recorded. The analysis of these spectra indicate the carrier is the I2 B3Π+0,u-X1Σ+g transition. DF spectra can be well explained by emission of the I2 B-X transition originating from a specific B state vibrational level to various X state vibrational levels. The waveforms and their pressure dependence experiments were also conducted. These results also confirm the carrier of these DF spectra is I2. Additionally, the pressure dependence experiments of C2, unknown bands, and I2 were carried out to verify the formation mechanism of these species.
