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Ding Y, Greenman L, Rolles D. Surface hopping molecular dynamics simulation of ultrafast methyl iodide photodissociation mapped by Coulomb explosion imaging. Phys Chem Chem Phys 2024; 26:22423-22432. [PMID: 39140357 DOI: 10.1039/d4cp01679c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
We present a highly efficient approach to directly and reliably simulate photodissociation followed by Coulomb explosion of methyl iodide. In order to achieve statistical reliability, more than 40 000 trajectories are calculated on accurate potential energy surfaces of both the neutral molecule and the doubly charged cation. Non-adiabatic effects during photodissociation are treated using a Landau-Zener surface hopping algorithm. The simulation is performed analogous to a recent pump-probe experiment using coincident ion momentum imaging [Ziaee et al., Phys. Chem. Chem. Phys., 2023, 25, 9999-10010]. At large pump-probe delays, the simulated delay-dependent kinetic energy release signals show overall good agreement with the experiment, with two major dissociation channels leading to I(2P3/2) and I*(2P1/2) products. At short pump-probe delays, the simulated kinetic energy release differs significantly from the values obtained by a purely Coulombic approximation or a one-dimensional description of the dicationic potential energy surfaces, and shows a clear bifurcation near 12 fs, owing to non-adiabatic transitions through a conical intersection. The proposed approach is particularly suitable and efficient in simulating processes that highly rely on statistics or for identifying rare reaction channels.
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Affiliation(s)
- Yijue Ding
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA.
| | - Loren Greenman
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA.
| | - Daniel Rolles
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA.
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2
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Wang J, Dong B, Zhang M, Deng Y, Jian X, Li Z, Liu Y. Ultrafast Imaging of Jahn-Teller Distortion and the Correlated Proton Migration in Photoionized Cyclopropane. J Am Chem Soc 2024; 146:10443-10450. [PMID: 38530937 DOI: 10.1021/jacs.3c13999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
The Jahn-Teller (JT) distortion is one of the fundamental processes in molecules and condensed phase matters. For photoionized organic molecules with high symmetry, the JT effect leads to geometric instability in certain electron configurations and thus has a significant effect on the subsequent isomerization and proton migration processes. Utilizing the femtosecond pump-probe Coulomb explosion method, we probe the isomerization dynamics process of a monovalent cyclopropane cation (C3H6+) caused by proton migration and reveal the relationship between proton migration and JT distortion. We found that the C3H6+ cation evolves from the D3h symmetric equilateral triangle geometry either to the acute triangle via two elongated C-C bonds (JT1) or to the obtuse triangle via a single elongated C-C bond (JT2). The JT1 pathway does not involve proton migration, while the JT2 pathway drives proton migration and can be mapped into the indirect dissociation channel of Coulomb explosion. The time-resolved experiment indicates that the delay time between those two JT pathways can be as large as ∼600 fs. After the JT distortion, the cyclopropane cation undergoes a subsequent structural evolution, which brings a greater variety of dissociation channels.
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Affiliation(s)
- Jiguo Wang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Bowen Dong
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Ming Zhang
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Yongkai Deng
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Xiaopeng Jian
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Zheng Li
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Peking University Yangtze Delta Institute of Optoelectronics, Nantong, Jiangsu 226010, China
| | - Yunquan Liu
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Center for Applied Physics and Technology, HEDPS, Peking University, Beijing 100871, China
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3
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Guo Z, Zhang M, Dong X, Wang J, Li Z, Liu Y. Probing Conical Intersection in the Multipathway Isomerization of CH 3Cl Using Coulomb Explosion. J Phys Chem Lett 2024; 15:2369-2374. [PMID: 38393833 DOI: 10.1021/acs.jpclett.3c03404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
Ubiquitous ultrafast isomerization is paramount in photoexcited molecules, in which non-adiabatic coupling among multiple electronic states can occur. We use the pump-probe Coulomb explosion imaging method to study the isomerization of CH3Cl molecules. We find that the isomerization under our strong field pump-probe scheme proceeds along multiple pathways, which are encoded in several distinct branches of the time-resolved kinetic energy release spectra for the CH2++HCl+ Coulomb explosion channel. Apart from the isomerized dissociative pathway in neutral and cationic excited states, the pump laser can also induce coherent vibrational dynamics in two coupled intermediate states and set up the initial conditions for the two concurrently proceeding isomerization pathways. The isomerization of CH3Cl provides an intriguing example of a chemical reaction consisting of multiple pathways and non-adiabatic dynamics.
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Affiliation(s)
- Zhenning Guo
- State Key Laboratory for Mesoscopic Physics and Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Ming Zhang
- State Key Laboratory for Mesoscopic Physics and Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Xiaolong Dong
- State Key Laboratory for Mesoscopic Physics and Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Jiguo Wang
- State Key Laboratory for Mesoscopic Physics and Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Zheng Li
- State Key Laboratory for Mesoscopic Physics and Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Yangtze Delta Institute of Optoelectronics, Peking University, Nantong, Jiangsu 226010, China
| | - Yunquan Liu
- State Key Laboratory for Mesoscopic Physics and Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Center for Applied Physics and Technology, HEDPS, Peking University, Beijing 100871, China
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4
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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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Gong X, Plésiat É, Palacios A, Heck S, Martín F, Wörner HJ. Attosecond delays between dissociative and non-dissociative ionization of polyatomic molecules. Nat Commun 2023; 14:4402. [PMID: 37479730 PMCID: PMC10361961 DOI: 10.1038/s41467-023-40120-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 07/12/2023] [Indexed: 07/23/2023] Open
Abstract
The interplay between electronic and nuclear motions in molecules is a central concept in molecular science. To what extent it influences attosecond photoionization delays is an important, still unresolved question. Here, we apply attosecond electron-ion coincidence spectroscopy and advanced calculations that include both electronic and nuclear motions to study the photoionization dynamics of CH4 and CD4 molecules. These molecules are known to feature some of the fastest nuclear dynamics following photoionization. Remarkably, we find no measurable delay between the photoionization of CH4 and CD4, neither experimentally nor theoretically. However, we measure and calculate delays of up to 20 as between the dissociative and non-dissociative photoionization of the highest-occupied molecular orbitals of both molecules. Experiment and theory are in quantitative agreement. These results show that, in the absence of resonances, even the fastest nuclear motion does not substantially influence photoionization delays, but identify a previously unknown signature of nuclear motion in dissociative-ionization channels. These findings have important consequences for the design and interpretation of attosecond chronoscopy in molecules, clusters, and liquids.
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Affiliation(s)
- Xiaochun Gong
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093, Zürich, Switzerland.
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200241, China.
| | - Étienne Plésiat
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Alicia Palacios
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Institute of Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Saijoscha Heck
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093, Zürich, Switzerland
| | - Fernando Martín
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nano), Cantoblanco, 28049, Madrid, Spain.
- Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049, Madrid, Spain.
| | - Hans Jakob Wörner
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093, Zürich, Switzerland.
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Crane SW, Lee JWL, Ashfold MNR, Rolles D. Molecular photodissociation dynamics revealed by Coulomb explosion imaging. Phys Chem Chem Phys 2023. [PMID: 37335247 DOI: 10.1039/d3cp01740k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Coulomb explosion imaging (CEI) methods are finding ever-growing use as a means of exploring and distinguishing the static stereo-configurations of small quantum systems (molecules, clusters, etc). CEI experiments initiated by ultrafast (femtosecond-duration) laser pulses also allow opportunities to track the time-evolution of molecular structures, and thereby advance understanding of molecular fragmentation processes. This Perspective illustrates two emerging families of dynamical studies. 'One-colour' studies (employing strong field ionisation driven by intense near infrared or single X-ray or extreme ultraviolet laser pulses) afford routes to preparing multiply charged molecular cations and exploring how their fragmentation progresses from valence-dominated to Coulomb-dominated dynamics with increasing charge and how this evolution varies with molecular size and composition. 'Two-colour' studies use one ultrashort laser pulse to create electronically excited neutral molecules (or monocations), whose structural evolution is then probed as a function of pump-probe delay using an ultrafast ionisation pulse along with time and position-sensitive detection methods. This latter type of experiment has the potential to return new insights into not just molecular fragmentation processes but also charge transfer processes between moieties separating with much better defined stereochemical control than in contemporary ion-atom and ion-molecule charge transfer studies.
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Affiliation(s)
- Stuart W Crane
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
| | - Jason W L Lee
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | | | - Daniel Rolles
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS 66506, USA
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7
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Ridente E, Hait D, Haugen EA, Ross AD, Neumark DM, Head-Gordon M, Leone SR. Femtosecond symmetry breaking and coherent relaxation of methane cations via x-ray spectroscopy. Science 2023; 380:713-717. [PMID: 37141314 DOI: 10.1126/science.adg4421] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Understanding the relaxation pathways of photoexcited molecules is essential to gain atomistic level insight into photochemistry. Herein, we performed a time-resolved study of ultrafast molecular symmetry breaking via geometric relaxation (Jahn-Teller distortion) on the methane cation. Attosecond transient absorption spectroscopy with soft X-rays at the carbon K-edge revealed that the distortion occurred within 10 ± 2 femtoseconds after few-femtosecond strong-field ionization of methane. The distortion activated coherent oscillations in the asymmetric scissoring vibrational mode of the symmetry broken cation, which were detected in the X-ray signal. These oscillations were damped within 58 ± 13 femtoseconds, as vibrational coherence was lost with the energy redistributing into lower-frequency vibrational modes. This study completely reconstructs the molecular relaxation dynamics of this prototypical example and opens new avenues for exploring complex systems.
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Affiliation(s)
- Enrico Ridente
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Diptarka Hait
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Eric A Haugen
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Andrew D Ross
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Martin Head-Gordon
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Department of Physics, University of California, Berkeley, CA 94720, USA
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8
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Crane SW, Lee JWL, Ashfold MNR. Multi-mass velocity map imaging study of the 805 nm strong field ionization of CF 3I. Phys Chem Chem Phys 2022; 24:18830-18840. [PMID: 35904364 DOI: 10.1039/d2cp02449g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multi-mass velocity map imaging studies of charged fragments formed by near infrared strong field ionization together with covariance map image analysis offer a new window through which to explore the dissociation dynamics of several different highly charged parent cations, simultaneously - as demonstrated here for the case of CF3IZ+ cations with charges Z ranging from 1 to at least 5. Previous reports that dissociative ionization of CF3I+ cations yields CF3+, I+ and CF2I+ fragment ions are confirmed, and some of the CF3+ fragments are deduced to undergo secondary loss of one or more neutral F atoms. Covariance map imaging confirms the dominance of CF3+ + I+ products in the photodissociation of CF3I2+ cations and, again, that some of the primary CF3+ photofragments can shed one or more F atoms. Rival charge symmetric dissociation pathways to CF2I+ + F+ and to IF+ + CF2+ products and charge asymmetric dissociations to CF3 + I2+ and CF2I2+ + F products are all also identified. The findings for parent cations with Z ≥ 3 are wholly new. In all cases, the fragment recoil velocity distributions imply dissociation dynamics in which coulombic repulsive forces play a dominant role. The major photoproducts following dissociation of CF3I3+ ions are CF3+ and I2+, with lesser contributions from the rival CF2I2+ + F+ and CF32+ + I+ channels. The CF32+ fragment ion images measured at higher incident intensities show a faster velocity sub-group consistent with their formation in tandem with I2+ fragments, from photodissociation of CF3I4+ parent ions. The measured velocity distributions of the I3+ fragment ions contain features attributable to CF3I5+ photodissociation to CF32+ + I3+ and the images of fragments with mass to charge (m/z) ratio ∼31 show formation of I4+ products that must originate from parent ions with yet higher Z.
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Affiliation(s)
- Stuart W Crane
- School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
| | - Jason W L Lee
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK.,Deutsches Elektronen-Synchrotron DESY, D-22607 Hamburg, Germany
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Zhang M, Guo Z, Mi X, Li Z, Liu Y. Ultrafast Imaging of Molecular Dynamics Using Ultrafast Low-Frequency Lasers, X-ray Free Electron Lasers, and Electron Pulses. J Phys Chem Lett 2022; 13:1668-1680. [PMID: 35147438 DOI: 10.1021/acs.jpclett.1c03916] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The requirement of high space-time resolution and brightness is a great challenge for imaging atomic motion and making molecular movies. Important breakthroughs in ultrabright tabletop laser, X-ray, and electron sources have enabled the direct imaging of evolving molecular structures in chemical processes, and recent experimental advances in preparing ultrafast laser and electron pulses resulted in molecular imaging with femtosecond time resolution. This Perspective presents an overview of the versatile imaging methods of molecular dynamics. High-order harmonic generation imaging and photoelectron diffraction imaging are based on laser-induced ionization and rescattering processes. Coulomb explosion imaging retrieves molecular structural information by detecting the momentum vectors of fragmented ions. Diffraction imaging encodes molecular structural and electronic information in reciprocal space. We also present various applications of these ultrafast imaging methods in resolving laser-induced nuclear and electronic dynamics.
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Affiliation(s)
- Ming Zhang
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Zhengning Guo
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Xiaoyu Mi
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
| | - Zheng Li
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Yangtze Delta Institute of Optoelectronics, Peking University, Nantong 226010, China
| | - Yunquan Liu
- State Key Laboratory for Mesoscopic Physics and Collaborative Innovation Center of Quantum Matter, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Center for Applied Physics and Technology, HEDPS, Peking University, Beijing 100871, China
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