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Tehlar A, Casanova JT, Dnestryan A, Jensen F, Madsen LB, Tolstikhin OI, Wörner HJ. High-harmonic spectroscopy of impulsively aligned 1,3-cyclohexadiene: Signatures of attosecond charge migration. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2024; 11:014304. [PMID: 38444565 PMCID: PMC10913099 DOI: 10.1063/4.0000227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 02/02/2024] [Indexed: 03/07/2024]
Abstract
High-harmonic spectroscopy is an all-optical technique with inherent attosecond temporal resolution that has been successfully employed to reconstruct charge migration, electron-tunneling dynamics, and conical-intersection dynamics. Here, we demonstrate the extension of two key components of high-harmonic spectroscopy, i.e., impulsive alignment and measurements with multiple driving wavelengths to 1,3-cyclohexadiene and benzene. In the case of 1,3-cyclohexadiene, we find that the temporal sequence of maximal and minimal emitted high-harmonic intensities as a function of the delay between the alignment and probe pulses inverts between 25 and 30 eV and again between 35 and 40 eV when an 800-nm driver is used, but no inversions are observed with a 1420-nm driver. This observation is explained by the wavelength-dependent interference of emission from multiple molecular orbitals (HOMO to HOMO-3), as demonstrated by calculations based on the weak-field asymptotic theory and accurate photorecombination matrix elements. These results indicate that attosecond charge migration takes place in the 1,3-cyclohexadiene cation and can potentially be reconstructed with the help of additional measurements. Our experiments also demonstrate a pathway toward studying photochemical reactions in the molecular frame of 1,3-cyclohexadiene.
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Affiliation(s)
- Andres Tehlar
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Jakob T. Casanova
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | | | - Frank Jensen
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - Lars Bojer Madsen
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | | | - Hans Jakob Wörner
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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Hasegawa H, Matsuda A, Morishita T, Madsen LB, Jensen F, Tolstikhin OI, Hishikawa A. Dissociative ionization and Coulomb explosion of CH 4 in two-color asymmetric intense laser fields. Phys Chem Chem Phys 2023; 25:25408-25419. [PMID: 37706318 DOI: 10.1039/d3cp02337k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
Directional fragment ejection from a tetrahedral molecule CH4 in linearly polarized two-color (ω and 2ω) asymmetric intense laser fields (50 fs, 1.4 × 1014 W cm-2, 800 nm and 400 nm) has been studied by three-dimensional ion coincidence momentum imaging. The H+ fragment produced from dissociative ionization, CH4 → H+ + CH3 + e-, is preferentially ejected on the larger amplitude side of the laser electric fields. Comparison with theoretical predictions by weak-field asymptotic theory shows that the observed asymmetry can be understood by the orientation selective tunneling ionization from the triply degenerated highest occupied molecular orbital (1t2) of CH4. A similar directional ejection of H+ was also observed for the low kinetic energy components of the two-body Coulomb explosion, CH4 → H+ + CH3+ + 2e-. On the other hand, the fragment ejection in the opposite direction were observed for the high energy component, as well as H2+ produced from the Coulomb explosion CH4 → H2+ + CH2+ + 2e-. Possible origins of the characteristic fragmentation are discussed.
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Affiliation(s)
- H Hasegawa
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan.
| | - A Matsuda
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan.
| | - T Morishita
- Institute for Advanced Science, The University of Electro-Communications, 1-5-1 Chofu-ga-oka, Chofu-shi, Tokyo 182-8585, Japan
| | - L B Madsen
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - F Jensen
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - O I Tolstikhin
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
| | - A Hishikawa
- Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan.
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan
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Hasegawa H, Walmsley T, Matsuda A, Morishita T, Madsen LB, Jensen F, Tolstikhin OI, Hishikawa A. Asymmetric Dissociative Tunneling Ionization of Tetrafluoromethane in ω − 2ω Intense Laser Fields. Front Chem 2022; 10:857863. [PMID: 35494655 PMCID: PMC9047872 DOI: 10.3389/fchem.2022.857863] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/22/2022] [Indexed: 11/30/2022] Open
Abstract
Dissociative ionization of tetrafluoromethane (CF4) in linearly polarized ω-2ω ultrashort intense laser fields (1.4 × 1014 W/cm2, 800 and 400 nm) has been investigated by three-dimensional momentum ion imaging. The spatial distribution of CF3+ produced by CF4 → CF3+ + F + e− exhibited a clear asymmetry with respect to the laser polarization direction. The degree of the asymmetry varies by the relative phase of the ω and 2ω laser fields, showing that 1) the breaking of the four equivalent C-F bonds can be manipulated by the laser pulse shape and 2) the C-F bond directed along the larger amplitude side of the ω-2ω electric fields tends to be broken. Weak-field asymptotic theory (WFAT) shows that the tunneling ionization from the 4t2 second highest-occupied molecular orbital (HOMO-1) surpasses that from the 1t1 HOMO. This predicts the enhancement of the tunneling ionization with electric fields pointing from F to C, in the direction opposite to that observed for the asymmetric fragment ejection. Possible mechanisms involved in the asymmetric dissociative ionization, such as post-ionization interactions, are discussed.
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Affiliation(s)
- Hiroka Hasegawa
- Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Tiffany Walmsley
- Graduate School of Science, Nagoya University, Nagoya, Japan
- School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Akitaka Matsuda
- Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Toru Morishita
- Institute for Advanced Science, The University of Electro-Communications, Chofu-shi, Tokyo, Japan
| | - Lars Bojer Madsen
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark
| | - Frank Jensen
- Department of Chemistry, Aarhus University, Aarhus, Denmark
| | | | - Akiyoshi Hishikawa
- Graduate School of Science, Nagoya University, Nagoya, Japan
- Research Center for Materials Science, Nagoya University, Nagoya, Japan
- *Correspondence: Akiyoshi Hishikawa,
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Fujise H, Uemura M, Hasegawa H, Ikeya D, Matsuda A, Morishita T, Madsen LB, Jensen F, Tolstikhin OI, Hishikawa A. Helicity-dependent dissociative tunneling ionization of CF 4 in multicycle circularly polarized intense laser fields. Phys Chem Chem Phys 2022; 24:8962-8969. [PMID: 35380001 DOI: 10.1039/d1cp05858d] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dissociative tunneling ionization of tetrafluoromethane (CF4) in circularly polarized ultrashort intense laser fields (35 fs, 0.8 × 1014 W cm-2, 1035 nm), CF4 → CF4+ + e- → CF3+ + F + e-, has been studied by three-dimensional electron-ion coincidence momentum imaging. The photoelectron angular distribution in the recoil frame revealed that the dissociative tunneling ionization occurs efficiently when the laser electric field points from F to C. The obtained results are qualitatively consistent with the theoretical predictions by the weak-field asymptotic theory (WFAT) for tunneling ionization from the highest and next-highest occupied molecular orbitals, HOMO (1t1), and HOMO-1 (4t2), respectively. On the other hand, the angular distribution shows clear dependences on the polarization helicity, indicating that the breaking of the C-F bonds is sensitive to the helicity of the multicycle circularly polarized laser fields.
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Affiliation(s)
- H Fujise
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan.
| | - M Uemura
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan.
| | - H Hasegawa
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan.
| | - D Ikeya
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan.
| | - A Matsuda
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan.
| | - T Morishita
- Institute for Advanced Science, The University of Electro-Communications, 1-5-1 Chofu-ga-oka, Chofu-shi, Tokyo 182-8585, Japan
| | - L B Madsen
- Department of Physics and Astronomy, Aarhus University, 8000 Aarhus C, Denmark
| | - F Jensen
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - O I Tolstikhin
- Moscow Institute of Physics and Technology, Dolgoprudny 141700, Russia
| | - A Hishikawa
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan. .,Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
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