本實驗室先前以266 nm光解碘化甲烷類分子 (iodomethanes) 時發現光解二碘甲烷 (CH2I2) 及碘甲烷 (CH3I) 的放射光譜 (nascent emission spectrum) 中有發現到共同之未知譜帶，其範圍由535 nm延伸至830 nm，我們分析其放射光譜的資訊得到相關分子的振動參數。而在本研究中，我們進一步去激發數根譜帶並取得其螢光分光光譜 (dispersed fluorescence spectrum) ，而分析螢光分光光譜結果顯示下能階之振動頻率分別為ω1為200±2 cm-1，ω2為421±2 cm-1，而螢光分光光譜的結果也同時驗證了放射光譜之標示正確，即這些未知譜帶皆由同一上能階放射至不同下能階，比照其他文獻及相關實驗推測可能的分子為C2I。此外，激發551 nm譜帶所得的螢光分光光譜與其他螢光分光光譜在結構上有明顯不同，因此推論在此譜帶可能有較複雜之能階結構存在。 Previous study of our group on the 266 nm photolysis of iodomethanes found that the nascent emission spectrum following the photolysis of CH2I2 and that of CH3I have some common unknown bands that appear from 535 nm to 830 nm. The analysis of nascent emission spectra yields the vibrational structures. In this study, laser-induced dispersed fluorescence (DF) spectra following excitation of some unknown bands were successfully obtained and the analysis of these DF spectra show the lower level vibrational structure with ω1= 200±2 cm-1 and ω2= 421±2 cm-1. These results confirm the assignments in the nascent emission spectrum that the emission bands originate from the same upper level to different lower levels. Based on the known frequencies of the related molecules, the carrier molecule is speculated to be C2I. In addition, the DF spectrum of exciting the 551 nm band shows a different vibrational structure. This implies the existence of more complicated energy structures in the lower levels.
