利用50 fs的激光脉冲对氯丙烯在200、400和800 nm下的光电离/解离机理进行了研究。 实验获得了氯丙烯在三种波长下的电离质谱和光强指数,分析了母体和碎片离子强度随波长的变化关系。 在200 nm, C3 H5 Cl + 来源于飞秒脉冲的直接非共振电离,其它碎片离子均来源于母体离子的电离解 离过程;在400 nm,部分分子被激发到高里德堡态从而解离产生C3 H5 , C3 H5 再次吸收光子电离导 致C3 H + 5的信号增强;在800 nm,部分分子被同时激发到了排斥态nσ和多个高里德堡态而发生 解离。更多通道产生C3 H5 使得C3 H + 5产量进一步增加。C3 H + 4来自C3 H5 Cl + 以及C3 H + 5的电离解离 过程,因此C3 H + 4产率随波长变化相对较缓。

The photoionization/photodissociation mechanism of allyl chloride was investigated with a 50 fs laser pulse at 200, 400 and 800 nm. With the ionization mass spectra and light intensity index recorded at three different wavelengths, the dependence of strength of the parent and fragment ions with the wavelength was analyzed. It was found that the parent ion (C3 H5 Cl + ) comes from directly non-resonance ionization with 200 nm femtosecond pulse, while the daughter ions are from dissociative ionization of C3 H5 Cl + . At 400 nm, some molecules are excited to the high Rydberg state and C3 H5 radicals are generated by direct dissociation. The enhancement of C3 H + 5 signal is observed since multi-photon ionization of C3 H5 increases the population of C3 H + 5. At 800 nm, nσ states and some Rydberg states are both populated. The further increased population of C3 H5 leads to an increase of C3 H + 5. The wavelength dependence of C3 H + 4 yield is less pronounced, since it comes from dissociative ionization of C3 H + 5 and C3 H5 Cl + .