Strong-field ionization of water. II. Electronic and nuclear dynamics en route to double ionization
| Autor: | Thomas Weinacht, Michael Spanner, Andrew J. Howard, Philip H. Bucksbaum, Ruaridh Forbes, Chuan Cheng, C. William McCurdy, Zachary L. Streeter, Robert R. Lucchese |
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| Rok vydání: | 2021 |
| Předmět: |
General Physics
Field (physics) Atomic Physics (physics.atom-ph) Double ionization physics.chem-ph FOS: Physical sciences physics.atom-ph Mathematical Sciences Physics - Atomic Physics Ion Fragmentation (mass spectrometry) Physics - Chemical Physics Ionization Physics::Atomic and Molecular Clusters Physics::Atomic Physics Chemical Physics (physics.chem-ph) Physics Dication Dipole Deuterium Physical Sciences Chemical Sciences physics.optics Atomic physics Physics - Optics Optics (physics.optics) |
| Zdroj: | Physical Review A, vol 104, iss 2 |
| Popis: | We investigate the role of nuclear motion and strong-field-induced electronic couplings during the double ionization of deuterated water using momentum-resolved coincidence spectroscopy. By examining the three-body dicationic dissociation channel, D$^{+}$/D$^{+}$/O, for both few- and multi-cycle laser pulses, strong evidence for intra-pulse dynamics is observed. The extracted angle- and energy-resolved double ionization yields are compared to classical trajectory simulations of the dissociation dynamics occurring from different electronic states of the dication. In contrast with measurements of single photon double ionization, pronounced departure from the expectations for vertical ionization is observed, even for pulses as short as 10~fs in duration. We outline numerous mechanisms by which the strong laser field can modify the nuclear wavefunction en-route to final states of the dication where molecular fragmentation occurs. Specifically, we consider the possibility of a coordinate-dependence to the strong-field ionization rate, intermediate nuclear motion in monocation states prior to double ionization, and near-resonant laser-induced dipole couplings in the ion. These results highlight the fact that, for small and light molecules such as D$_2$O, a vertical-transition treatment of the ionization dynamics is not sufficient to reproduce the features seen experimentally in the strong field coincidence double-ionization data. Comment: 14 pages, 13 figures |
| Databáze: | OpenAIRE |
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