Post-Ionization Dynamics of the Polar Molecule OCS in Asymmetric Laser Fields

Frontiers in Chemistry

François Légaré²  Heide Ibrahim²  Friedrich G. Fröbel³  Martin Richter³  Tomoyuki Endo⁴  Stefanie Gräfe⁵  Karl Michael Ziems⁵  Akiyoshi Hishikawa⁶ 

[1] Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan;Institut national de la recherche scientifique, Centre Énergie Matériaux et Télécommunications, Varennes, QC, Canada;Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University Jena, Jena, Germany;Kansai Photon Science Institute, National Institutes for Quantum Science and Technology, Kizugawa, Japan;Max Planck School of Photonics, Jena, Germany;Research Center for Materials Science, Nagoya University, Nagoya, Japan;

关键词: two-color laser field;    coherent control experiment;    post-ionization dynamics;    real-time real-space time-dependent density functional theory;    Coulomb explosion imaging;   

DOI  :  10.3389/fchem.2022.859750

来源: DOAJ

【 摘 要 】

We have investigated the dissociation mechanisms of the prototypical heavy polar molecule OCS into the two break-up channels of the dication, OCS2+ → O+ + CS+ and OC+ + S+, in phase-locked two-color intense laser fields. The branching ratio of the breaking of the C–O and C–S bonds followed a pronounced 2π-oscillation with a modulation depth of 11%, depending on the relative phase of the two-color laser fields. The fragment ejection direction of both break-up channels reflects the anisotropy of the tunneling ionization rate, following a 2π-periodicity, as well. The two dissociation pathways in the C–S bond breaking channel show different phase dependencies of the fragment ejection direction, which are assigned to post-ionization dynamics. These observations, resulting from the excitation with asymmetric two-color intense laser fields, supported by state-of-the-art theoretical simulations, reveal the importance of post-ionization population dynamics in addition to tunneling ionization in the molecular fragmentation processes, even for heavy polar molecules.

【 授权许可】

Unknown