Angle dependence of strong-field single and double ionization of carbonyl sulfide
| Autor: | Péter Sándor, Timothy T. Gorman, Kenneth Lopata, Mette B. Gaarde, Kenneth J. Schafer, Paul M. Abanador, Francois Mauger, Robert Jones, Timothy D. Scarborough, Adonay Sissay |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Preferential alignment 010304 chemical physics Linear polarization Double ionization Time-dependent density functional theory Laser 01 natural sciences Molecular physics law.invention chemistry.chemical_compound Delocalized electron chemistry law Ionization 0103 physical sciences Physics::Atomic and Molecular Clusters 010306 general physics Carbonyl sulfide |
| Zdroj: | Physical Review A. 98 |
| ISSN: | 2469-9934 2469-9926 |
| DOI: | 10.1103/physreva.98.043425 |
| Popis: | We have studied, experimentally and theoretically, the ionization probability of carbonyl sulfide (OCS) molecules in intense linearly polarized 800-nm laser pulses as a function of the angle between the molecular axis and the laser polarization. Experimentally, the molecules are exposed to two laser pulses with a relative time delay. The first, weaker pulse induces a nuclear rotational wave packet within each molecule such that the ensemble exhibits preferential alignment in the laboratory frame at specific times. The second, stronger pulse induces ionization, and the variation in single and double ionization yields is measured as a function of the delay between the two pulses. The angular dependence of the ionization yield is extracted by fitting the delay-dependent yields to a sum of delay-dependent moments of the rotational wave packet's angular distribution. We compute these same angular-dependent strong-field ionization yields for OCS using time-dependent density-functional theory (TDDFT). For the single-ionization case, our measurements agree well with TDDFT calculations and with previous experiments. Furthermore, analysis of the simulated one-body density reveals that, when averaged over a laser cycle, the resulting hole is delocalized across the molecule for light polarized perpendicular to the molecular axis and mostly localized on the sulfur for parallel polarization. This suggests that preferential molecular alignment is a key parameter for controlling charge migration dynamics initiated by strong-field ionization. For double ionization, the agreement between experiment and theory is less compelling, reflecting the substantial challenges of computing double-ionization yields using TDDFT methods. |
| Databáze: | OpenAIRE |
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