101
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Kobayashi Y, Chang KF, Zeng T, Neumark DM, Leone SR. Direct mapping of curve-crossing dynamics in IBr by attosecond transient absorption spectroscopy. Science 2019; 365:79-83. [DOI: 10.1126/science.aax0076] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/11/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Yuki Kobayashi
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Kristina F. Chang
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Tao Zeng
- Department of Chemistry, Carleton University, Ottawa, Ontario K1S5B6, Canada
| | - Daniel M. Neumark
- 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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102
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Marangos JP. The measurement of ultrafast electronic and structural dynamics with X-rays. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20170481. [PMID: 30929630 PMCID: PMC6452056 DOI: 10.1098/rsta.2017.0481] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/04/2019] [Indexed: 05/17/2023]
Abstract
In this theme issue, leading researchers discuss recent work on the measurement of ultrafast electronic and structural dynamics in matter using a new generation of short duration X-ray photon sources. These photon sources, based upon high harmonic generation from lasers and X-ray free-electron lasers, look set to have a high impact on ultrafast science. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.
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103
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Agostini F, Curchod BFE. Different flavors of nonadiabatic molecular dynamics. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2019. [DOI: 10.1002/wcms.1417] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Federica Agostini
- Laboratoire de Chimie Physique UMR 8000 CNRS/University Paris‐Sud Orsay France
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104
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The photochemical ring-opening of 1,3-cyclohexadiene imaged by ultrafast electron diffraction. Nat Chem 2019; 11:504-509. [DOI: 10.1038/s41557-019-0252-7] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 03/07/2019] [Indexed: 11/09/2022]
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105
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Murakami T, Frankcombe TJ. Non-adiabatic quantum molecular dynamics by the basis expansion leaping multi-configuration Gaussian (BEL MCG) method: Multi-set and single-set formalisms. J Chem Phys 2019; 150:144112. [DOI: 10.1063/1.5084749] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Tatsuhiro Murakami
- School of Science, University of New South Wales, Canberra, ACT 2600, Australia
| | - Terry J. Frankcombe
- School of Science, University of New South Wales, Canberra, ACT 2600, Australia
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106
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Zhao L, Wang Z, Tang H, Wang R, Cheng Y, Lu C, Jiang T, Zhu P, Hu L, Song W, Wang H, Qiu J, Kostin R, Jing C, Antipov S, Wang P, Qi J, Cheng Y, Xiang D, Zhang J. Terahertz Oscilloscope for Recording Time Information of Ultrashort Electron Beams. PHYSICAL REVIEW LETTERS 2019; 122:144801. [PMID: 31050450 DOI: 10.1103/physrevlett.122.144801] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Indexed: 05/09/2023]
Abstract
We propose and demonstrate a terahertz (THz) oscilloscope for recording time information of an ultrashort electron beam. By injecting a laser-driven THz pulse with circular polarization into a dielectric tube, the electron beam is swept helically such that the time information is uniformly encoded into the angular distribution that allows one to characterize both the temporal profile and timing jitter of an electron beam. The dynamic range of the measurement in such a configuration is significantly increased compared to deflection with a linearly polarized THz pulse. With this THz oscilloscope, nearly 50-fold longitudinal compression of a relativistic electron beam to about 15 fs (rms) is directly visualized with its arrival time determined with 3 fs accuracy. This technique bridges the gap between streaking of photoelectrons with optical lasers and deflection of relativistic electron beams with radio-frequency deflectors, and should have wide applications in many ultrashort electron-beam-based facilities.
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Affiliation(s)
- Lingrong Zhao
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhe Wang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Heng Tang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rui Wang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yun Cheng
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chao Lu
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Tao Jiang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pengfei Zhu
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
| | - Long Hu
- Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shanxi 710024, China
| | - Wei Song
- Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shanxi 710024, China
| | - Huida Wang
- Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shanxi 710024, China
| | - Jiaqi Qiu
- Nuctech Company Limited, Beijing 100084, China
| | - Roman Kostin
- Euclid Techlabs LLC, Bolingbrook, Illinois 60440, USA
| | | | | | - Peng Wang
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Jia Qi
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Ya Cheng
- State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
| | - Dao Xiang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
- Tsung-Dao Lee Institute, Shanghai 200240, China
| | - Jie Zhang
- Key Laboratory for Laser Plasmas (Ministry of Education), School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Collaborative Innovation Center of IFSA (CICIFSA), Shanghai Jiao Tong University, Shanghai 200240, China
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107
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Imaging the Renner-Teller effect using laser-induced electron diffraction. Proc Natl Acad Sci U S A 2019; 116:8173-8177. [PMID: 30952783 DOI: 10.1073/pnas.1817465116] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Structural information on electronically excited neutral molecules can be indirectly retrieved, largely through pump-probe and rotational spectroscopy measurements with the aid of calculations. Here, we demonstrate the direct structural retrieval of neutral carbonyl disulfide (CS2) in the [Formula: see text] excited electronic state using laser-induced electron diffraction (LIED). We unambiguously identify the ultrafast symmetric stretching and bending of the field-dressed neutral CS2 molecule with combined picometer and attosecond resolution using intrapulse pump-probe excitation and measurement. We invoke the Renner-Teller effect to populate the [Formula: see text] excited state in neutral CS2, leading to bending and stretching of the molecule. Our results demonstrate the sensitivity of LIED in retrieving the geometric structure of CS2, which is known to appear as a two-center scatterer.
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108
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Abstract
A review that summarizes the most recent technological developments in the field of ultrafast structural dynamics with focus on the use of ultrashort X-ray and electron pulses follows. Atomistic views of chemical processes and phase transformations have long been the exclusive domain of computer simulators. The advent of femtosecond (fs) hard X-ray and fs-electron diffraction techniques made it possible to bring such a level of scrutiny to the experimental area. The following review article provides a summary of the main ultrafast techniques that enabled the generation of atomically resolved movies utilizing ultrashort X-ray and electron pulses. Recent advances are discussed with emphasis on synchrotron-based methods, tabletop fs-X-ray plasma sources, ultrabright fs-electron diffractometers, and timing techniques developed to further improve the temporal resolution and fully exploit the use of intense and ultrashort X-ray free electron laser (XFEL) pulses.
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109
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Scarborough TD, McAcy CJ, Beck J, Uiterwaal CJGJ. Comparison of ultrafast intense-field photodynamics in aniline and nitrobenzene: stability under amino and nitro substitution. Phys Chem Chem Phys 2019; 21:6553-6558. [PMID: 30848265 DOI: 10.1039/c8cp07866a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report on the photoionization and photofragmentation of aniline (C6H5NH2) and nitrobenzene (C6H5NO2) under single-molecule conditions in the focus of 50 fs, 800 nm laser pulses. Ion mass spectra are recorded as a function of intensity ranging from 6 × 1012 to 3 × 1014 W cm-2. Ion yields are measured in the absence of the focal volume effect and without the need for additional deconvolution of data. We observe evidence of resonance-enhanced multiphoton ionization in aniline, in agreement with current literature. Phenyl-based ion fragments, singly-charged parent ions, and dissociative rearrangement processes are observed for both molecules. However, fragmentation in aniline is heavily suppressed in favor of parent ionization while the reverse is true for nitrobenzene, and multiply-charged parent ions are present in aniline and absent in nitrobenzene. We discuss the implications of these and other results as they relate to molecular stability against intense-field ionization and fragmentation, specifically with regards to the opposing behavior of the substituted amino and nitro functional groups.
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Affiliation(s)
- Timothy D Scarborough
- Physics Research Building, Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA.
| | - Collin J McAcy
- Theodore Jorgensen Hall, Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Joshua Beck
- Theodore Jorgensen Hall, Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
| | - Cornelis J G J Uiterwaal
- Theodore Jorgensen Hall, Department of Physics and Astronomy, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
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110
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Abstract
A proposal for building a Free Electron Laser, EuPRAXIA@SPARC_LAB, at the Laboratori Nazionali di Frascati, is at present under consideration. This FEL facility will provide a unique combination of a high brightness GeV-range electron beam generated in a X-band RF linac, a 0.5 PW-class laser system and the first FEL source driven by a plasma accelerator. The FEL will produce ultra-bright pulses, with up to 10 12 photons/pulse, femtosecond timescale and wavelength down to 3 nm, which lies in the so called “water window”. The experimental activity will be focused on the realization of a plasma driven short wavelength FEL able to provide high-quality photons for a user beamline. In this paper, we describe the main classes of experiments that will be performed at the facility, including coherent diffraction imaging, soft X-ray absorption spectroscopy, Raman spectroscopy, Resonant Inelastic X-ray Scattering and photofragmentation measurements. These techniques will allow studying a variety of samples, both biological and inorganic, providing information about their structure and dynamical behavior. In this context, the possibility of inducing changes in samples via pump pulses leading to the stimulation of chemical reactions or the generation of coherent excitations would tremendously benefit from pulses in the soft X-ray region. High power synchronized optical lasers and a TeraHertz radiation source will indeed be made available for THz and pump–probe experiments and a split-and-delay station will allow performing XUV-XUV pump–probe experiments.
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111
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Parrish RM, Martínez TJ. Ab Initio Computation of Rotationally-Averaged Pump-Probe X-ray and Electron Diffraction Signals. J Chem Theory Comput 2019; 15:1523-1537. [PMID: 30702882 DOI: 10.1021/acs.jctc.8b01051] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We develop a new algorithm for the computation of the rotationally averaged elastic molecular diffraction signal for the cases of perpendicular or parallel pump-probe geometries. The algorithm first collocates the charge density from an arbitrary ab initio wave function onto a Becke quadrature grid [A. Becke, J. Chem. Phys. 1988 , 88 , 2457 ], providing a high-fidelity multiresolution representation of the charge density. A double sum is then performed over the Becke grid points, and the interaction between points computed using the scattering kernels of Williamson and Zewail [J. C. Williamson and A. H. Zewail, J. Phys. Chem. 1994 , 98 , 2766 ]. These kernels analytically average over the molecular orientations with the cos2 γ selection factor appropriate for one-photon dipole absorption in a perpendicular pump-probe geometry. We show that the method is converged with small grids containing <500 points/atom. We implement the algorithm on a GPU for increased efficiency and emonstrate the algorithm for molecules with up to a few dozen atoms. We explore the accuracy of the independent atom model (IAM) by comparison with our new and more accurate method. We also investigate the possibility of detecting signatures of electronic transitions in polyatomic pump-probe diffraction experiments.
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Affiliation(s)
- Robert M Parrish
- Department of Chemistry and The PULSE Institute , Stanford University , Stanford , California 94305 , United States.,SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
| | - Todd J Martínez
- Department of Chemistry and The PULSE Institute , Stanford University , Stanford , California 94305 , United States.,SLAC National Accelerator Laboratory , 2575 Sand Hill Road , Menlo Park , California 94025 , United States
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112
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Ischenko AA, Kochikov IV, Miller RJD. The effect of Coulomb repulsion on the space-time resolution limits for ultrafast electron diffraction. J Chem Phys 2019; 150:054201. [PMID: 30736672 DOI: 10.1063/1.5060673] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The development of electron sources capable of temporal resolution on the order of 1 ps or less raises a number of questions associated with the estimation of the physical meaning and accuracy of the dynamic parameters based on the analysis of time-dependent scattering intensity. The use of low brightness ultrashort pulses with few electrons leads to the necessity for increasing the total exposure time and lengthening the time of data acquisition, with attendant problems with the limited sample. The sample restrictions can be mitigated by increasing the charge per pulse, i.e., by going to high brightness sources. Increasing in the number of electrons, however, is limited by the Coulomb repulsion between them, which leads on one hand to distortion of the diffraction pattern and on the other hand to an increase in the duration of the pulse. An analytical technique for estimating the deformation of the diffraction pattern caused by the Coulomb repulsion of the electrons in electron bunches with duration of less than 10 ps and the influence of this effect on the accuracy of determination of the interatomic distances is developed for the non-relativistic and relativistic regimes for electron energies.
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Affiliation(s)
- A A Ischenko
- Institute of Fine Chemical Technologies named after M.V. Lomonosov, Russian Technological University-MIREA, Prosp. Vernadskogo 86, 119571 Moscow, Russian Federation
| | - I V Kochikov
- Research Computing Center, Lomonosov Moscow State University, 119899 Moscow, Russian Federation
| | - R J Dwayne Miller
- The Max Planck Institute for the Structure and Dynamics of Matter Hamburg, Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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113
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Rather SR, Scholes GD. From Fundamental Theories to Quantum Coherences in Electron Transfer. J Am Chem Soc 2019; 141:708-722. [PMID: 30412671 DOI: 10.1021/jacs.8b09059] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Photoinduced electron transfer (ET) is a cornerstone of energy transduction from light to chemistry. The past decade has seen tremendous advances in the possible role of quantum coherent effects in the light-initiated energy and ET processes in chemical, biological, and materials systems. The prevalence of such coherence effects holds a promise to increase the efficiency and robustness of transport even in the face of energetic or structural disorder. A primary motive of this Perspective is to work out how to think about "coherence" in ET reactions. We will discuss how the interplay of basic parameters governing ET reactions-like electronic coupling, interactions with the environment, and intramolecular high-frequency quantum vibrations-impact coherences. This includes revisiting the insights from the seminal work on the theory of ET and time-resolved measurements on coherent dynamics to explore the role of coherences in ET reactions. We conclude by suggesting that in addition to optical spectroscopies, validating the functional role of coherences would require simultaneous mapping of correlated electron motion and atomically resolved nuclear structure.
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Affiliation(s)
- Shahnawaz R. Rather
- Frick Chemistry Laboratory , Princeton University , Princeton , New Jersey 08544 , United States
| | - Gregory D Scholes
- Frick Chemistry Laboratory , Princeton University , Princeton , New Jersey 08544 , United States
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114
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Warne EM, Downes-Ward B, Woodhouse J, Parkes MA, Bellshaw D, Springate E, Majchrzak P, Zhang Y, Karras G, Wyatt AS, Chapman RT, Kirrander A, Minns RS. Photodissociation dynamics of CH3I probed via multiphoton ionisation photoelectron spectroscopy. Phys Chem Chem Phys 2019; 21:11142-11149. [DOI: 10.1039/c9cp01477b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond photoelectron spectroscopy measurements of dissociation CH3I show complex dynamics in the high energy region of absorption band A.
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115
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Hada M, Shigeeda Y, Koshihara SY, Nishikawa T, Yamashita Y, Hayashi Y. Bond Dissociation Triggering Molecular Disorder in Amorphous H 2O. J Phys Chem A 2018; 122:9579-9584. [PMID: 30430832 DOI: 10.1021/acs.jpca.8b08455] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We developed a system to deposit H2O molecules onto ultrathin silicon nitride substrates in situ using time-resolved transmission electron diffraction apparatus and performed ultrafast time-resolved electron diffraction measurements in the noncrystalline (amorphous) H2O under near-ultraviolet photoexcitation. The observed dynamics directly represent O-H bond dissociation via multiphoton absorption and charge transfer, which trigger ionization and intermolecular disorder in the amorphous H2O. Our results illustrate the intriguing nature of light-matter and matter-matter interactions in H2O molecules.
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Affiliation(s)
- Masaki Hada
- Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - Yuho Shigeeda
- Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - Shin-Ya Koshihara
- School of Science , Tokyo Institute of Technology , Tokyo 152-8551 , Japan
| | - Takeshi Nishikawa
- Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - Yoshifumi Yamashita
- Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
| | - Yasuhiko Hayashi
- Graduate School of Natural Science and Technology , Okayama University , Okayama 700-8530 , Japan
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116
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Li F, Ma Y, Liu J, Wang F. Parent bending effects on nonadiabatic transition dynamics: Isotopomer-resolved imaging of photodissociation of CF 3Br at two source temperatures. J Chem Phys 2018; 149:124303. [PMID: 30278672 DOI: 10.1063/1.5047927] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nonadiabatic transition between electronic states plays a critical role in the photodissociation of the CX3Y (X = H and F; Y = Cl, Br, and I) system, and the transition probability was considered to be closely related to the X-C-Y bending motion. Hereby the effect of F-C-Br bending vibration on the nonadiabatic transition dynamics is studied by time-sliced ion velocity imaging of Br(2P1/2,3/2) isotopomers produced from the photodissociation of title molecules at two source temperatures, 298 K and 473 K, respectively. At the photolysis wavelength 234 nm, the anisotropy parameter (β) of the Br(2P3/2) products decreases from 1.3 at 298 K to 0.9 at 473 K, while the β of Br(2P1/2) remains at almost 2 at two temperatures, indicating the significant effect of bending excitation on the ground channel. Two nonadiabatic dissociation pathways are suggested in the Br(2P3/2) channel. One of them is the parallel excitation from the ground state to the 3 Q 0 state in C3V symmetry, and then transition to the 1 Q 1 state via conical intersection, and the other is the perpendicular excitation to the 3A' state in Cs symmetry and then decomposition along this state in the presence of the avoided crossing between 3A' and 4A' states. Closely related to the F-C-Br bending vibration of CF3Br is the latter transition.
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Affiliation(s)
- Fangfang Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials, Fudan University, Shanghai 200433, People's Republic of China
| | - Yujie Ma
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials, Fudan University, Shanghai 200433, People's Republic of China
| | - Jiaxing Liu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials, Fudan University, Shanghai 200433, People's Republic of China
| | - Fengyan Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials, Fudan University, Shanghai 200433, People's Republic of China
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117
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Li S, Cropp F, Kabra K, Lane TJ, Wetzstein G, Musumeci P, Ratner D. Electron Ghost Imaging. PHYSICAL REVIEW LETTERS 2018; 121:114801. [PMID: 30265113 DOI: 10.1103/physrevlett.121.114801] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Indexed: 06/08/2023]
Abstract
In this Letter we report a demonstration of electron ghost imaging. A digital micromirror device directly modulates the photocathode drive laser to control the transverse distribution of a relativistic electron beam incident on a sample. Correlating the structured illumination pattern to the total sample transmission then retrieves the target image, avoiding the need for a pixelated detector. In our example, we use a compressed sensing framework to improve the reconstruction quality and reduce the number of shots compared to raster scanning a small beam across the target. Compressed electron ghost imaging can reduce both acquisition time and sample damage in experiments for which spatially resolved detectors are unavailable (e.g., spectroscopy) or in which the experimental architecture precludes full frame direct imaging.
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Affiliation(s)
- S Li
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - F Cropp
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - K Kabra
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - T J Lane
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - G Wetzstein
- Department of Electrical Engineering, Stanford University, Stanford, California 94305, USA
| | - P Musumeci
- Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - D Ratner
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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118
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Affiliation(s)
- Helen H. Fielding
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
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