标题: | 利用步进式扫描时域解析傅氏转换红外光谱法研究CH3OSO之红外吸收光谱 Infrared absorption spectra of CH3OSO detected with step-scan time-resolved Fourier-transform spectroscopy |
作者: | 陈劲达 Chen, Jin-Dah 李远鹏 应用化学系硕博士班 |
关键字: | 傅氏转换;红外吸收光谱;Fourier-transform;infrared absorption spectrum;CH3OSO;methoxy sulfinyl |
公开日期: | 2010 |
摘要: | 利用步进式扫描时间解析傅氏转换红外光谱仪搭配多重吸收槽,侦测CH3OS(O)Cl/N2或CH3OS(O)Cl/CO2气体混合样品经248 nm雷射光解产生CH3OSO于2991、2956、1152及994 cm-1之瞬态吸收谱带。其中1152 cm-1之谱带可指派为syn-CH3OSO的S=O振动与CH2左右摆动混合模(ν8,1154 ± 3 cm-1)与S=O振动与CH2上下摆动混合模(ν9,1151 ± 3 cm-1)的贡献,而994 cm-1之谱带则可指派为C-O伸张振动模(ν10,994 ± 6 cm-1)的贡献。而在2991及2956 cm-1之强度较弱的谱带则可指派为syn-CH3OSO的CH3反对称伸张振动模(ν2,2991 ± 6 cm-1)与CH3对称伸张振动模(ν3,2956 ± 3 cm-1)的贡献。根据理论计算B3P86/aug-cc-pVTZ预测之振动基态与激发态转动常数与偶极矩导数,吾人利用光谱模拟程式SpecView模拟各个振动模的振转动谱带,其轮廓与实验光谱相当吻合。此外,anti-CH3OSO之S=O伸张振动模(ν7,1164 cm-1)可能对1152 cm-1之谱带有少许贡献。根据吾人假设之动力学模型,可得到CH3OSO自体反应之二级反应常数k5 = (4 ± 2) × 10-10 cm3 molecule-1 s-1。 A step-scan Fourier-transform spectrometer coupled with a multipass absorption cell was employed to detect temporally resolved infrared absorption spectra of CH3OSO produced upon irradiation of a flowing gaseous mixture of CH3OS(O)Cl in N2 or CO2 at 248 nm. Two intense transient features with origins near 1152 and 994 cm-1 are assigned to syn-CH3OSO; the former is attributed to overlapping bands at 1154 ± 3 and 1151 ± 3 cm-1, assigned to the S=O stretching mixed with CH2 rocking (ν8) and the S=O stretching mixed with CH2 wagging (ν9) modes, respectively, and the latter to the C□O stretching (ν10) mode at 994 ± 6 cm-1. Two weak bands at 2991 ± 6 and 2956 ± 3 cm-1 are assigned as the CH3 antisymmetric stretching (ν2) and symmetric stretching (ν3) modes, respectively. Observed vibrational transition wavenumbers agree satisfactorily with those predicted with quantum-chemical calculations at level B3P86/aug-cc-pVTZ. Based on rotational parameters predicted at that level, the simulated rotational contours of these bands agree satisfactorily with experimental results. The simulation indicates that the S=O stretching mode of anti-CH3OSO near 1164 cm-1 likely makes a small contribution to the observed band near 1152 cm-1. A simple kinetic model of self-reaction is employed to account for the decay of CH3OSO and yields a second order rate coefficient k = (4 ± 2)×10-10 cm3 molecule-1 s-1. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079825506 http://hdl.handle.net/11536/47593 |
显示于类别: | Thesis |
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