利用离子速度成像方法对碘代直链烷烃和环烷烃分子在267 nm下的光解断键机理进行了研究.实验分析了激发态I*(5p2P1/2)和基态I(5p2P3/2)的离子影像,得到其对应速度、角度分布的各向异性参数β值和相对量子产率Φ(I)和Φ(I*).实验发现碘代直链烷烃和环烷烃分子在吸收一个267nm的光子后,都发生快速的C-I断键,直接解离生成激发态I*和基态I原子.与碘代直链烷烃相比,碘代环烷烃分子具有明显不同的角度分布特征,碘代环烷烃分子基态的β值大于激发态.并且随着α碳原子上所取代的烷基变重,Φ(I*)有变小的趋势.
参考文献
| [1] | Yung Y L,Pinto J P,et al.Atmospheric bromine and ozone perturbations in the lower stratosphere[J].J.Atmos.Sci.,1980,37:339-353. |
| [2] | Brewer P,Das P,Ondrey G S.Measurement of the relative populations of I(2p0 1/2)and I(2p0 3/2)by laser induced vacuum ultraviolet fluorescence[J].J.Chem.Phys.,1983,79(2):720-723. |
| [3] | Tang Y,Ji L,Zhu R S,et al.Photodissociation study of ethyl bromide in the ultraviolet range by the ion-velocity imaging technique[J].Chem.Phys.Chem.,2005,6:2137-2144. |
| [4] | Liu Y,Butler L J.C-Cl bond fission dynamics and angular momentum recouping in the 235 nm photodissociation of allyl chloride[J].J.Chem.Phys.,2004,121:11016-11022. |
| [5] | Zhang Liang,Li Xia,Zhang Shian,et al.Selective enhancement of coherent anti-Stokes Ptaman scattering from dibromomethane by adaptive feedback control[J].Chinese Journal of Quantum Electronics(量子电子学报),2007,24(6):694-698(in Chinese). |
| [6] | Mulliken R S.Intensities in molecular electronic spectra X.calculations on mixed-halogen,hydrogen halide,alkyl halide,and hydroxyl spectra[J].J.Chem.Phys.,1940,8:382-395. |
| [7] | Dura J,Nalda R,et al.Femtosecond transition-state imaging of the A-band CH3I photodissociation[J].Chem.Phys.Chem.,2008,9:1245-1249. |
| [8] | Eppink A T J B,Parker D H.Energy partition following photodissociation of methyl iodide in the A band:a velocity mapping study[J].J.Chem.Phys.,110(2):832-843. |
| [9] | Tang Y,Lee W B,Hu Z,et al.Productions of I,I*,and C2H5 in the A-band photodissociation of ethyl iodide in the wavelength range from 245 to 283 nm by using ion-imaging detection[J].J.Chem.Phys.,2007,126:064302. |
| [10] | Fan H,Pratt S T.Photoionization of hot radicals:C2H5,n-C3H7,and i-C3H7[J].J.Chem.Phys.,2005,123:204301. |
| [11] | Eppink A T J B,Parker D H.Methyl iodide A-band decomposition study by photofragment velocity imaging[J].J.Chem.Phys.,1998,109:4758-4767. |
| [12] | Zhang Feng,Cao Zhenzhou,Qin Xiao,et al.C-Br bond dissociation mechanisms of 2-bromothiophene and 3-bromothiophene at 267 nm[J].Acta Phys.Chim.Sin.(物理化学学报),2008,24(8):1335(in Chinese). |
| [13] | Donovan R J,Flood R V,Lawley K P,et al.The resonance enhanced(2+1)multiphoton ionization spectrum of I2[J].Chem.Phys.,1992,164(3):439-450. |
| [14] | Riley S J,Wilson K R.Excited fragments from excited molecules:energy partitioning in the photodissociation of alkyl iodides[J].Faraday Discuss.Chem.Soc.,1972,53:132-146. |
| [15] | Kim Y S,Kang W K,et al.Photodissociation of tert-butyl iodide at 277 and 304 nm:evidence for direct and indirect dissociation in A-band photolysis of alkyl iodide[J].J.Phys.Chem.A,1997,101:7576-7581. |
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