405nm飞秒强激光场中H_2的碎裂研究（英文）

Fragmentation of H_2 in 405 nm intense femtosecond laser field

使用速度成像法测得了405 nm飞秒激光脉冲下H^+的动能分布和角分布。讨论了解离通道H_2^+→H^++H、H_2^(2+)→H^++H^+的反应路径,前者产生于经由1ω交叉的直接单光子路径,后者产生于H_2^(2+)的库仑爆炸。H_2^+到H_2^(2+)的电离起始于键软化,各通道的相对峰高说明H_2^+的解离和电离是竞争的。低场强加强H_2^+的解离,高场强支持H_2^+的电离。

The kinetic energy and angular distributions of H^＋ as a function of 405 nm femtosecond laser intensity are experimentally measured by using velocity map imaging technique. The reaction pathways of dissociation channels, H2^＋ → H^＋ ＋ H and H2^2＋ → H^＋ ＋ H^＋, are discussed. The former is due to the direct one-photon pathway via the lw crossing, and the latter stems from Coulomb explosion of H2^2＋. Ionization of H2^＋ to H2^2＋ starts from bond softening. The relative yield of fragment peak indicates that dissociation and ionization of H2^＋ are competitive. The lower laser intensity emphasizes the dissociation of H2^＋, and the higher laser intensity favors the ionization of H2^＋.