Molecular tunneling ionization of the carbonyl sulfide molecule by double-frequency phase-controlled laser fields
Molecular tunneling ionization of the carbonyl sulfide molecule by double-frequency phase-controlled laser fields
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DOI：
10.1103/physreva.89.013405
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发表时间：
2014-01
影响因子：
2.9
通讯作者：
H. Ohmura;N. Saito;T. Morishita
中科院分区：
文献类型：
--
作者：
H. Ohmura;N. Saito;T. Morishita
我们研究了线性偏振双频相控激光场诱导的羰基硫（OCS）分子的定向选择性分子隧道电离，该激光场由基波光和二次谐波光组成，脉冲持续时间为 130 fs，强度为 5 \ifmmode\times\else\texttimes\fi{} 10${}^{13}$ W/cm${}^{2}$。我们使用 OCS 和一氧化碳的气体混合物进行同步测量，以校准相控场的相对相位差并验证隧道电离的机制。证明了电离分子的取向与最高占据分子轨道的结构之间存在明确的相关性。我们利用弱场渐近理论讨论了实验结果。此外，我们还分析了离子电子同步检测中光电子的量子动力学。实验结果可以通过包括与母离子相互作用的两步模型来解释。再碰撞过程对于确定在所使用的实验激光强度下隧道电离中极性分子的优选方向起着次要作用。
We have investigated the orientation-selective molecular tunneling ionization of carbonyl sulfide (OCS) molecules induced by linearly polarized double-frequency phase-controlled laser fields consisting of a fundamental and a second-harmonic light with a pulse duration of 130 fs and an intensity of 5 \ifmmode\times\else\texttimes\fi{} 10${}^{13}$ W/cm${}^{2}$. We performed simultaneous measurements using gas mixtures of OCS and carbon monoxide to calibrate the relative phase difference of the phase-controlled fields and to verify the mechanism of the tunnel ionization. It is demonstrated that there is a definite correlation between the orientation of ionized molecules and the structure of the highest occupied molecular orbital. We have discussed the experimental results by means of the weak field asymptotic theory. In addition, we have analyzed the quantum dynamics of photoelectrons in simultaneous ion-electron detection. The experimental results can be explained by a two-step model including the interaction with the parent ion. The recollision process plays a minor role for determining the preferable directions of polar molecules in the tunneling ionization at the experimental laser intensity used.