论文部分内容阅读
利用飞秒激光脉冲,在200、400和800 nm下对氯丙烯(C_3H_5Cl)的光解离和电离动力学进行了研究。实验测量了氯丙烯在飞秒脉冲作用下的飞行时间质谱、光强指数以及光电子影像。结果发现在短波(200 nm)时,母体分子的电离为主要通道,而其他离子均来源于C_3H_5Cl~+的解离。当波长移动到长波(800 nm)时,碎片离子就占据了主导。这些碎片离子来源于中性碎片的多光子电离过程,而这些中性碎片又是由C_3H_5Cl的中间态直接解离而产生的。这意味着,光解离过程起到非常重要的作用。这是因为800 nm可以激发分子达到能够产生中性碎片的中间态。在400 nm时,虽然中间态的解离过程仍然至关重要,但并没有在800 nm时明显。综上所述,本文的研究证实了氯丙烯的光解离/电离行为具有波长依赖性,并揭示了氯丙烯在200、400和800 nm飞秒激光作用下的复杂动力学过程。
The photodissociation and ionization kinetics of allyl chloride (C_3H_5Cl) were investigated at femtosecond laser pulses at 200, 400 and 800 nm. The time-of-flight mass spectrometry, light intensity index and photoelectron imaging of allyl chloride with femtosecond pulse were measured. The results showed that in the short wavelength (200 nm), the ionization of the parent molecule is the main channel, while the other ions are derived from the dissociation of C_3H_5Cl ~ +. Fragments of ions dominate as the wavelength moves to longer wavelengths (800 nm). These fragment ions originate from the multiphoton ionization process of neutral fragments, which are generated by the direct dissociation of the intermediate state of C_3H_5Cl. This means that the photodissociation process plays a very important role. This is because 800 nm can excite molecules to an intermediate state capable of producing neutral fragments. At 400 nm, although the dissociation of the intermediate state is still crucial, it is not apparent at 800 nm. In summary, the present study confirms the wavelength dependence of the photodissociation / ionization behavior of allyl chloride and reveals the complex kinetics of allyl chloride at 200, 400 and 800 nm femtosecond laser.