Ionization of molecules irradiated by intense laser fields

研究了强激光场作用下分子的电离过程。对于乙炔，分子轴垂直于激光偏振方向时，单电荷和双电荷乙炔离子的离子产额比平行于激光偏振方向时大。我们发现，这种行为反映了最高占据分子轨道（HOMO）的形状。结果，乙炔中的电子通过激光电场的隧道电离或过势垒电离而被电离。此外，在氧分子的情况下，单电荷离子的离子产额表现出类似乙炔的行为。另一方面，我们发现双电荷氧分子的离子产额不同于乙炔和单电荷氧分子。

We studied the ionization processes of molecules irradiated by intense laser fields. In the case of acetylene, the ion yield of singly charged and doubly charged acetylene ions is larger when molecular axis is perpendicular to laser polarization direction than parallel to that. We revealed that this behavior reflects the shape of the highest occupied molecular orbital (HOMO). As a result, electrons in acetylene are ionized by tunnel ionization or over barrier ionization of the laser electric fields. In addition, in the case of oxygen molecule, the ion yield of singly charged ion behaves like acetylene. On the other hand, we found that the ion yield of the doubly charged oxygen molecule is different from acetylene and singly charged oxygen molecule.