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Abstract
The reactivity and dynamics of molecular systems can be explored computationally by classical trajectory calculations. The traditional approach involves fitting a functional form of a potential energy surface (PES) to the energies from a large number of electronic structure calculations and then integrating numerous trajectories on this fitted PES to model the molecular dynamics. The ever-decreasing cost of computing and continuing advances in computational chemistry software have made it possible to use electronic structure calculations directly in molecular dynamics simulations without first having to construct a fitted PES. In this "on-the-fly" approach, every time the energy and its derivatives are needed for the integration of the equations of motion, they are obtained directly from quantum chemical calculations. This approach started to become practical in the mid-1990s as a result of increased availability of inexpensive computer resources and improved computational chemistry software. The application of direct dynamics calculations has grown rapidly over the last 25 years and would require a lengthy review article. The present Account is limited to some of our contributions to methods development and various applications. To improve the efficiency of direct dynamics calculations, we developed a Hessian-based predictor-corrector algorithm for integrating classical trajectories. Hessian updating made this even more efficient. This approach was also used to improve algorithms for following the steepest descent reaction paths. For larger molecular systems, we developed an extended Lagrangian approach in which the electronic structure is propagated along with the molecular structure. Strong field chemistry is a rapidly growing area, and to improve the accuracy of molecular dynamics in intense laser fields, we included the time-varying electric field in a novel predictor-corrector trajectory integration algorithm. Since intense laser fields can excite and ionize molecules, we extended our studies to include electron dynamics. Specifically, we developed code for time-dependent configuration interaction electron dynamics to simulate strong field ionization by intense laser pulses. Our initial application of ab initio direct dynamics in 1994 was to CH2O → H2 + CO; the calculated vibrational distributions in the products were in very good agreement with experiment. In the intervening years, we have used direct dynamics to explore energy partitioning in various dissociation reactions, unimolecular dissociations yielding three fragments, reactions with branching after the transition state, nonstatistical dynamics of chemically activated molecules, dynamics of molecular fragmentation by intense infrared laser pulses, selective activation of specific dissociation channels by aligned intense infrared laser fields, angular dependence of strong field ionization, and simulation of sequential double ionization.
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Affiliation(s)
- H. Bernhard Schlegel
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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2
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Setting the photoelectron clock through molecular alignment. Nat Commun 2020; 11:2546. [PMID: 32439923 PMCID: PMC7242449 DOI: 10.1038/s41467-020-16270-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/16/2020] [Indexed: 11/09/2022] Open
Abstract
The interaction of strong laser fields with matter intrinsically provides a powerful tool for imaging transient dynamics with an extremely high spatiotemporal resolution. Here, we study strong-field ionisation of laser-aligned molecules, and show a full real-time picture of the photoelectron dynamics in the combined action of the laser field and the molecular interaction. We demonstrate that the molecule has a dramatic impact on the overall strong-field dynamics: it sets the clock for the emission of electrons with a given rescattering kinetic energy. This result represents a benchmark for the seminal statements of molecular-frame strong-field physics and has strong impact on the interpretation of self-diffraction experiments. Furthermore, the resulting encoding of the time-energy relation in molecular-frame photoelectron momentum distributions shows the way of probing the molecular potential in real-time, and accessing a deeper understanding of electron transport during strong-field interactions. Interaction of strong laser fields with matter provides powerful tools to image transient dynamics with high spatiotemporal resolution. The authors investigate strong-field ionisation of laser-aligned molecules showing the effect of molecular alignment on the photoelectron dynamics and the resulting influence of the molecular frame in imaging experiments.
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Richter M, González-Vázquez J, Mašín Z, Brambila DS, Harvey AG, Morales F, Martín F. Ultrafast imaging of laser-controlled non-adiabatic dynamics in NO2 from time-resolved photoelectron emission. Phys Chem Chem Phys 2019; 21:10038-10051. [PMID: 31046039 DOI: 10.1039/c9cp00649d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Imaging and controlling the ultrafast conical intersection dynamics in NO2 using the latest advances in attosecond and light-synthesizer technology.
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Affiliation(s)
- Maria Richter
- Departamento de Química
- Módulo 13
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
| | | | - Zdeněk Mašín
- Max-Born-Institute
- Max-Born-Straße 2A
- 12489 Berlin
- Germany
| | | | | | | | - Fernando Martín
- Departamento de Química
- Módulo 13
- Universidad Autónoma de Madrid
- 28049 Madrid
- Spain
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4
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Affiliation(s)
- Matthias F. Kling
- FOM Institute for Atomic and Molecular Physics, 1098 SJ Amsterdam, The Netherlands;
- Max-Planck Institut für Quantenoptik, D-85748 Garching, Germany
| | - Marc J.J. Vrakking
- FOM Institute for Atomic and Molecular Physics, 1098 SJ Amsterdam, The Netherlands;
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5
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Abstract
Femtosecond time-resolved photoelectron imaging (TRPEI) is a variant of time-resolved photoelectron spectroscopy used in the study of gas-phase photoinduced dynamics. A new observable, time-dependent photoionization-differential cross section provides useful information on wave-packet motions, electronic dephasing, and photoionization dynamics. This review describes fundamental issues and the most recent works involving TRPEI.
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Affiliation(s)
- Toshinori Suzuki
- Chemical Dynamics Laboratory, RIKEN (Institute of Physical and Chemical Research), Wako 351-0198, Japan.
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7
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Shalashilin DV, Child MS. Electronic energy levels with the help of trajectory-guided random grid of coupled wave packets. I. Six-dimensional simulation of H2. J Chem Phys 2005; 122:224108. [PMID: 15974652 DOI: 10.1063/1.1926268] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
As a preliminary to future work on the behavior of atoms and molecules in strong time-dependent fields, we apply the coupled coherent-states (CCS) technique of multidimensional phase-space quantum dynamics to obtain Born-Oppenheimer energy levels of electrons in molecules. Unlike traditional approaches based on atomic and molecular-orbital basis sets and time-independent Schrodinger equation the CCS method exploits the solution of the time-dependent Schrodinger equation in the basis of Monte Carlo-selected trajectory-guided coherent states, which treat classical electron correlations exactly. In addition the CCS trajectories move over averaged potentials, which remove the Coulombic singularities.
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Affiliation(s)
- Dmitrii V Shalashilin
- Physical and Theoretical Chemistry Laboratory Oxford University, South Parks Road, Oxford OX1 3QZ, United Kingdom.
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8
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Intermolecular motion in strong infrared laser fields. Chem Phys 2005. [DOI: 10.1016/j.chemphys.2004.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Itakura R, Yamanouchi K, Tanabe T, Okamoto T, Kannari F. Dissociative ionization of ethanol in chirped intense laser fields. J Chem Phys 2003. [DOI: 10.1063/1.1592504] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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10
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Suppression of decomposition of aniline cation in intense laser fields by cluster formation with NH3 and H2O. J Photochem Photobiol A Chem 2003. [DOI: 10.1016/s1010-6030(03)00020-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Verver RJ, Wright JS, Ivanov MY. Simulation of pump–probe spectroscopy of a highly-charged diatomic molecule: Role of intermediate charged states and electronic and vibrational excitation in the multiple ionization of Cl2 and strong-field spectroscopy of Cl23+. J Chem Phys 2002. [DOI: 10.1063/1.1506684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Watanabe J, Itakura R, Hishikawa A, Yamanouchi K. Suppression of decomposition of aniline cation in intense laser fields by cluster formation with ammonia molecules. J Chem Phys 2002. [DOI: 10.1063/1.1475753] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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Pettersson M, Zadoyan R, Eloranta J, Schwentner N, Apkarian VA. Strong-Field Excitation of Liquid and Solid Xe Using Intense Femtosecond Pulses. J Phys Chem A 2002. [DOI: 10.1021/jp0146317] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Pettersson
- Department of Chemistry, University of California, Irvine, California 92612-2025
| | - R. Zadoyan
- Department of Chemistry, University of California, Irvine, California 92612-2025
| | - J. Eloranta
- Department of Chemistry, University of California, Irvine, California 92612-2025
| | - N. Schwentner
- Department of Chemistry, University of California, Irvine, California 92612-2025
| | - V. A. Apkarian
- Department of Chemistry, University of California, Irvine, California 92612-2025
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Lezius M. A B-TOF mass spectrometer for the analysis of ions with extreme high start-up energies. JOURNAL OF MASS SPECTROMETRY : JMS 2002; 37:305-312. [PMID: 11921372 DOI: 10.1002/jms.286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Weak magnetic deflection is combined with two acceleration stage time-of-flight mass spectrometry and subsequent position-sensitive ion detection. The experimental method, called B-TOF mass spectrometry, is described with respect to its theoretical background and some experimental results. It is demonstrated that the technique has distinct advantages over other approaches, with special respect to the identification and analysis of very highly energetic ions with an initially large energy broadening (up to 1 MeV) and with high charge states (up to 30+). Similar energetic targets are a common case in intense laser-matter interaction processes found during laser ablation, laser-cluster and laser-molecule interaction and fast particle and x-ray generation from laser-heated plasma.
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Affiliation(s)
- M Lezius
- Institute for Ion Physics, University of Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria.
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15
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Spanner M, Ivanov MY. Angular trapping and rotational dissociation of a diatomic molecule in an optical centrifuge. J Chem Phys 2001. [DOI: 10.1063/1.1342225] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Gill R, Yanagawa R, Thachuk M. A semiclassical study of the photodissociation dynamics of a coupled two-surface model of HCl+ by an intense laser field in the long-wavelength limit. J Chem Phys 2000. [DOI: 10.1063/1.482024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zewail A. Femtochemie: Studium der Dynamik der chemischen Bindung auf atomarer Skala mit Hilfe ultrakurzer Laserpulse (Nobel-Aufsatz). Angew Chem Int Ed Engl 2000. [DOI: 10.1002/1521-3757(20000804)112:15<2688::aid-ange2688>3.0.co;2-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Engel V, Henriksen NE. Mapping of wave packets in direct fragmentation via pump–probe frequency integrated fluorescence spectroscopy. J Chem Phys 2000. [DOI: 10.1063/1.480566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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Bunker PR, Bludsky O, Jensen P, Wesolowski SS, Yamaguchi Y, Schaefer HF. The H(2)O(++) Ground State Potential Energy Surface. JOURNAL OF MOLECULAR SPECTROSCOPY 1999; 198:371-375. [PMID: 10547318 DOI: 10.1006/jmsp.1999.7970] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
At the correlation-consistent polarized-valence quadruple-zeta complete active space self-consistent field second-order configuration interaction level of ab initio theory (cc-pVQZ CASSCF-SOCI), we calculated 129 points on the ground electronic state potential energy surface of the water dication H(2)O(++); this calculation includes the energy of;X(3)Sigma(-) OH(+) at equilibrium and the energy of the triplet oxygen atom. We determined the parameters in an analytical function that represents this surface out to the (OH(+) + H(+)) and (O + 2H(+)) dissociation limits, for bending angles from 70 to 180 degrees. There is a metastable minimum in this surface, at an energy of 43 600 cm(-1) above the H(+) + OH(+) dissociation energy, and the geometry at this minimum is linear (D(infinityh)), with an OH bond length of 1.195 Å. On the path to dissociation to H(+) + OH(+), there is a saddle point at an energy of 530 cm(-1) above the minimum, and the geometry at the saddle point is linear (C(infinity Kv)) with OH bond lengths of 1.121 and 1.489 Å. Using the stabilization method, we calculated the lowest resonance on this surface. Relative to the metastable local minimum on the potential energy surface, the position of the lowest resonance for H(2)O(++), D(2)O(++), and T(2)O(++) is 1977(85), 1473(25), and 1249(10) cm(-1), respectively, where the width of each resonance (in cm(-1)) is given in parentheses. Copyright 1999 Academic Press.
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Affiliation(s)
- PR Bunker
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada
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Van Huis TJ, Wesolowski SS, Yamaguchi Y, Schaefer HF. Scratching the surface of the water dication. J Chem Phys 1999. [DOI: 10.1063/1.479127] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Structures in molecular photofragment and photoelectron distributions from two-photon non-resonant excitation. Chem Phys Lett 1999. [DOI: 10.1016/s0009-2614(98)01405-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Larsen JJ, Mo/rkbak NJ, Olesen J, Bjerre N, Machholm M, Keiding SR, Stapelfeldt H. Femtosecond photodissociation dynamics of I2 studied by ion imaging. J Chem Phys 1998. [DOI: 10.1063/1.477557] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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