Ion Imaging of MgI+ Photofragment in Ultraviolet Photodissociation Mass-selected Mg+ICH3 Complex
Ion Imaging of MgI+ Photofragment in Ultraviolet Photodissociation Mass-selected Mg+ICH3 Complex
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紫外光解离质量选择 Mg ICH3 配合物中 MgI 光碎片的离子成像
DOI：
10.1021/acs.jpca.8b01944
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发表时间：
2018
期刊：
影响因子：
2.9
通讯作者：
F. Misaizu
中科院分区：
文献类型：
--
作者：
K. Okutsu;K. Yamazaki;M. Nakano;K. Ohshimo;F. Misaizu
在266 nm波长下观察到了Mg ~+ ICH_3离子在紫外激光光解过程中产生的碎片离子图像。在光碎片图像中观察到几乎垂直于光解激光偏振方向的分裂分布。通过理论计算得到了Mg+ ICH 3的势能曲线。在这些曲线中，激发的络合离子沿着几乎排斥势解离，并避免了几个交叉点，这是连接到MgI++ CH 3。在Mg+ ICH 3的基态下，CH 3 I从碘侧与Mg键合，Mg-I-C键角为101.1°。理论计算结果还表明，解离发生在52 A ′ ← 12 A ′光激发之后，此时跃迁偶极矩几乎平行于Mg-I键轴. MgI+和CH 3碎片的解离方向平行于连接质心的方向，与52 A ′ <$12 A ′光激发的跃迁偶极矩成67°。因此，假设在快速解离过程中，碎片反冲方向接近垂直于极化方向的趋势。然而，计算的势能曲线显示了一个复杂的反应途径MgI+的生产，包括非绝热过程，虽然实验结果表明，快速解离反应。
We have observed images of MgI+fragment ions produced in ultraviolet laser photodissociation of mass-selected Mg+ICH3ions at 266 nm. Split distribution almost perpendicular to the polarization direction of the photolysis laser was observed in the photofragment image. Potential energy curves of Mg+ICH3were obtained by theoretical calculations. Among these curves, the excited complex ion dissociated along almost repulsive potentials with several avoided crossings, which was connected to MgI++ CH3. In the ground state of Mg+ICH3, the CH3I was bonded with Mg from the iodine side, and the Mg–I–C bond angle was calculated to be 101.1°. The theoretical results also indicated that the dissociation occurred after the 52A′ ← 12A′ photoexcitation, where the transition dipole moment was almost parallel to the Mg–I bond axis. The MgI+and CH3fragments dissociated each other parallel to the direction connecting those center-of-masses, which was 67° with respect to the transition dipole moment of 52A′ ← 12A′ photoexcitation. Therefore, the fragment recoil direction was assumed to approach perpendicular tendency against the polarization direction under the fast dissociation process. However, calculated potential energy curves showed a complicated reaction pathway for MgI+production, including nonadiabatic processes, although the experimental results indicated the fast dissociation reaction.