中文摘要：

运用飞行时间质谱的峰形模拟程序，对纳秒强光场下CH3I团簇电离过程中得到的离子峰进行模拟。根据模拟峰形与实验峰形的相似程度，直接反演出离子产生时的速度分布或空间分布，并根据速度或空间分布推测了离子产生的来源，其中C^2＋,I^2＋和I^3＋来源于库仑爆炸过程，C^＋，CHx^＋（x=1，2，3），I^＋和CH3I^＋来源于多光子电离过程，H^＋来源于上述两种过程，而少部分I^＋来源于电子碰撞电离。此外，通过峰形模拟，对离子的接收比例进行了研究。

英文摘要：

The peak profiles of ions from ionization of CH3I clusters in the nanosecond laser field were simulated using a peak shape simulation program of time-of-flight mass spectrometer （TOF-MS）. Ionic initial position and velocity distributions, which depended on the formation mechanism, were obtained by comparing the experimental and simulated peak shape, and the ion source was also illustrated. C^2＋ , I^2＋ and I^3＋ ions come from Coulomb explosion, while C^＋ , CHx^＋ （x=1, 2,3）, I^＋ and CH3I^＋ ions were formed by multiphoton ionization （MPI）. H^＋ is due to both Coulomb explosion and MPI, and a small portion of I^＋ origin from electron impact ionization. In addition, the acceptance ratio of ions was studied by the simulation method.