利用25纳秒脉冲Nd-YAG 532 nm的激光,在1011 W cm-2的光场强度下,用飞行时间质谱对不同载气条件下碘甲烷的激光电离过程进行了研究.当利用氩作为载气时,除观察到H+,C+,CH+,CH+3,I+,CH3I+等离子外,还观察到很强的C2+,I2+和I3+离子信号.这些高价离子的最可几平动能分别为55.5 eV,9.5 eV和27 eV.质谱峰形的分裂现象以及不同载气的实验结果表明这些高价离?涌赡芾丛从诘饧淄橥糯氐目饴乇ü?

The photoionization of methyl iodide seeded in He, N_2, Ar gases by a intense 25 ns Nd-YAG 532 nm laser has been studied by time-of-flight mass spectrometry. At the laser intensity about 10~(10)～10~(11) W cm~(-2). multi-charged ions C~(2+), I~(2+) and I~(3+) appeared in the mass spectra when Ar or He was used as carrier gas. From the peak splitting, the most probable kinetic energies of C~(2+), I~(3+) and I~(3+) are calculated to be 55.5 eV, 9.5 eV and 27 eV respectively. From the results under different conditions, it is proposed that the multi-charge ions are come from the coulomb explosion of methyl iodide cluster ions.