2,4–雙氟苯甲醚之第一電子激發態暨 離子態振動光譜
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2014
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Abstract
我們應用高解析度共振雙光子游離(R2PI)與質量解析臨界游離光譜法(MATI)，探討2,4–雙氟苯甲醚(2,4–difluoroanisole)的分子特性，精準地量測第一電子躍遷能與游離能，並記錄此分子的S1電子激發態和D0離子基態的振動光譜。D0離子基態光譜是利用第一電子激發態的00、X1、τCH3、151、9a1、6a1和11分子振動態為中間能階紀錄的。2,4–雙氟苯甲醚的第一電子躍遷能測得為35556 ± 2 cm-1，其游離能為67568 ± 5 cm-1。
在光譜上所看到大部份的振動模式，都和芳香環上的平面運動有關。比較本實驗所得到的2,4–雙氟苯甲醚和文獻上苯甲醚的光譜數據
，可以幫助我們了解氟的取代基效應在苯甲醚上，對電子躍遷和游離過程及分子振動的影響。另外我們也利用ab initio及密度泛函數理論計算來幫助我們進行分子光譜標定工作。
We applied the resonant two-photon ionization (R2PI) and mass-analyzed threshold ionization (MATI) spectroscopic techniques to record the vibronic and cation spectra of 2,4–difluoroanisole. The cation spectra were obtained by ionizing via the 00, X1, τCH3, 151, 9a1, 6a1, and 11 levels of the electronically excited S1 state. The band origin of the S1 ← S0 electronic transition of 2,4–difluoroanisole appears at 35556 ± 2 cm-1 and the adiabatic ionization energy is determined to be 67568 ± 5 cm-1. Most of the active vibrations of this molecule in the S1 and D0 states are related to in-plane vibrations of the aromatic ring. Comparing the experimental data of 2,4–difluoroanisole with those of anisole helps us learn the fluorine substitution affects on the electronic excitation and ionization processes as well as molecular vibration. We have also performed the ab initio and density functional calculations which help us in spectral assignment and support our experimental findings.
We applied the resonant two-photon ionization (R2PI) and mass-analyzed threshold ionization (MATI) spectroscopic techniques to record the vibronic and cation spectra of 2,4–difluoroanisole. The cation spectra were obtained by ionizing via the 00, X1, τCH3, 151, 9a1, 6a1, and 11 levels of the electronically excited S1 state. The band origin of the S1 ← S0 electronic transition of 2,4–difluoroanisole appears at 35556 ± 2 cm-1 and the adiabatic ionization energy is determined to be 67568 ± 5 cm-1. Most of the active vibrations of this molecule in the S1 and D0 states are related to in-plane vibrations of the aromatic ring. Comparing the experimental data of 2,4–difluoroanisole with those of anisole helps us learn the fluorine substitution affects on the electronic excitation and ionization processes as well as molecular vibration. We have also performed the ab initio and density functional calculations which help us in spectral assignment and support our experimental findings.
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共振雙光子游離光譜法, 質量解析臨界游離光譜法, 2, 4–雙氟苯甲醚, 第一電子躍遷能, 游離能, resonant two-photon ionization, mass-analyzed threshold ionization, 2, 4–difluoroanisole, vibronic spectra, cation spectra