以共振二光子游離及質量解析臨界游離光譜術研究間位甲氧基苯胺與鄰位甲氧基苯胺之分子特性

Resonant two-photon ionization and mass-analyzed threshold ionization spectroscopy of the selected rotamers of m-methoxyaniline and o-methoxyaniline

黃乾座(Chen Jso Huang)

指導教授 ： 曾文碧 ； 林震煌

國立臺灣師範大學/理學院/化學系/碩士(2006年)

摘要

中文摘要

我們應用高解析度共振雙光子游離與質量解析臨界游離光譜術來探討間位與鄰位甲氧基苯胺的分子特性，精準地量測第一電子躍遷能和游離能，並記錄這些分子的 S1電子激發態和D0離子基態的振動光譜。間位甲氧基苯胺有兩種轉動異構物，cis構形的第一電子躍遷能測得34308 ? 2 cm-1、而trans構形則為34495 ? 2 cm-1，它們的游離能分別為59983 ? 5 cm-1和60879 ? 5 cm-1。鄰位甲氧基苯胺的第一電子躍遷能為33875 ? 2 cm-1，而它的游離能則是58678 ? 5 cm-1。我們也進行量子化學及密度泛函數理論計算，並且以所測得的光譜和對位甲氧基苯胺及其他苯胺衍生物的實驗數據作比較，結果顯示大部分較為顯著的振動模式都為平面上苯環的振動，而取代基的特性與在苯環上的相關位置皆會對分子的躍遷能、游離能以及振動模式造成影響。

關鍵字

共振雙光子游離光譜術 ； 質量解析臨界游離光譜術 ； 間位甲氧基苯胺 ； 鄰位甲氧基苯胺 ； 游離能 ； 激發態振動光譜 ； 離子態振動光譜

並列摘要

We applied the high-resolution resonant two-photon ionization and mass-analyzed threshold ionization spectroscopy to study the molecular properties of m-methoxyaniline and o-methoxyaniline. m-Methoxyaniline has two rotamers. The origins of the S1 ← S0 electronic transition (E1’s) of the cis and trans rotamers are measured to be 34308 ± 2 and 34495 ± 2 cm-1 and their corresponding adiabatic ionization energies (IEs) are 59983 ± 5 and 60879 ± 5 cm-1, respetively. o-Methoxyaniline is found to have only one stable structure whose E1 and IE are determined to be 33875 ± 2 and 58678 ± 5 cm-1, respectively. Most of the active vibrations of m- and o-methoxyaniline in the electronically excited S1 and cationic ground D0 states result from the in-plane ring vibrations. Comparing these data with those of p-methoxyaniline and many aniline derivatives allows us to learn about the vicinal substitution effects resulting from the relative locations of the NH2 and OCH3 substituents. We have also performed the ab initio and density functional calculations to support our experimental findings.

參考文獻

[16]. J. L. Lin, K. C. Lin, W. B. Tzeng, J. Phys. Chem. A 106 (2002)

[4].A.W. Castleman, Jr., W. B. Tzeng, S. Wei, S. Morgan, J. Chem. Soc.

[43].M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery, Jr., T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S. Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G. Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J. E. Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala, K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V. G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O. Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J. Cioslowski, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, C. Gonzalez, J. A. Pople. GAUSSIAN 03, Revision C.02, Gaussian, Inc. Pittsburgh, (2003).

Press, Cambridge, U.K,(1998)

[2].J. Laane, Annu. Rev. Phys. Chem. 45 (1994) 179.