Imaging transient species in the femtosecond A-band photodissociation of CH3I.
Imaging transient species in the femtosecond A-band photodissociation of CH3I.
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DOI：
10.1063/1.3236808
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
J. Durá;R. de Nalda;G. Amaral;L. Bañares
中科院分区：
文献类型：
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作者：
J. Durá;R. de Nalda;G. Amaral;L. Bañares
采用中心波长为802 nm的非共振飞秒激光脉冲，在267 nm的A波段研究了CH（3）I分子的真实的时间光解动力学.利用探测激光脉冲的多光子电离和CH（3）（+）的速度图离子成像，我们跟踪了CH（3）碎片的平移能和空间各向异性的时间演化，这反过来又允许沿着反应坐标从初始的Franck-Condon区域到最终产物沿着成像C-I键断裂。给定我们的泵浦和探测激光脉冲的时间宽度（约80 fs），提出了一种机制，通过该机制，瞬态物种探测泵浦和探测激光脉冲通过中间里德堡和离子态的CH（3）I的同时吸收，而泵浦和探测脉冲在时间上重叠。这项研究表明，飞秒多光子电离和离子成像技术的组合提供了一个理想的工具，及时解决的不同阶段的键断裂事件在多原子分子。
A nonresonant femtosecond laser pulse centered at 802 nm is used to probe the real time photodissociation dynamics of CH(3)I in the A-band at 267 nm. Using multiphoton ionization with this probe laser pulse and velocity map ion imaging of CH(3)(+), we have followed the time evolution of the translational energy and spatial anisotropy of the CH(3) fragment, which in turn has permitted to image the C-I bond breaking from the initial Franck-Condon region up to the final products along the reaction coordinate. Given the temporal width of our pump and probe laser pulses (approximately 80 fs), a mechanism is proposed by which transient species are probed by simultaneous absorption of pump and probe laser pulses through intermediate Rydberg and ionic states of CH(3)I while the pump and probe pulses overlap in time. This study shows how the combination of femtosecond multiphoton ionization and ion imaging techniques provides an ideal tool to resolve in time the different stages of the bond breaking event in a polyatomic molecule.