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结合共振增强多光子电离(REMPI)方案,利用离子影像技术研究了n-C3H7I和i-C3H7I分子的光解动力学.分析和比较了它们光解过程中所涉及的能量分配和解离态间的非绝热跃迁信息.它们的I(2P3/2)产物通道的内能所占百分比要大于I*(2P1/2)产物通道的.随着烷烃自由基变得更加的分支化,一方面,原子碎片(I和I*)的能量分布明显变宽,暗示了α-碳原子上的烷基具有更复杂的振转模式;另一方面,在266nm光子的泵浦下,尽管两分子3Q0邝X跃迁的谐振强度表现出很小的差别,但是,产生I*碎片的几率明显降低,从n-C3H7I的0.72降到i-C3H7I的0.46.这可以归因于在光解i-C3H7I过程中弯曲振动模式对产生I和I*的贡献要比n-C3H7I光解过程中弯曲振动模式对I和I*的贡献更明显,使得3Q0与1Q1态之间的非绝热跃迁得到增强.此外,n-C3H7I和i-C3H7I的3Q0邝X跃迁并不完全是平行跃迁,对应的跃迁偶极矩与键轴间的夹角分别约为15°和18°.
Photodissociation kinetics of n-C3H7I and i-C3H7I molecules were studied using ion imaging technique in combination with the resonance-enhanced multiphoton ionization (REMPI) scheme. The energy partitioning and dissociation involved in their photolysis were analyzed and compared Non-adiabatic transitions. Their I (2P3 / 2) product channels have a greater percentage of internal energy than I * (2P1 / 2) product channels. As alkane radicals become more branched, The energy distribution of the fragments (I and I *) is obviously broadened, suggesting that the alkyl groups on α-carbon atoms have a more complex mode of oscillation. On the other hand, under the pumping of 266 nm photons, The resonance intensity of the transitions shows a small difference, however, the probability of producing I * fragments is significantly reduced from 0.72 of n-C3H7I to 0.46 of i-C3H7I This can be attributed to bending during photolysis of i-C3H7I The contribution of vibration mode to I and I * contribution is more significant than the bending vibration mode I and I * in the n-C3H7I photolysis process, so that the non-adiabatic transition between 3Q0 and 1Q1 states is enhanced.In addition, n- The 3Q0 Kuang X transitions of C3H7I and i-C3H7I are not completely parallel transitions. The corresponding angle of dip transition between the dipole moment and the key axis About 15 ° and 18 °.