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Chang KF, Wang H, Poullain SM, Prendergast D, Neumark DM, Leone SR. Mapping wave packet bifurcation at a conical intersection in CH 3I by attosecond XUV transient absorption spectroscopy. J Chem Phys 2021; 154:234301. [PMID: 34241252 DOI: 10.1063/5.0056299] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Extreme ultraviolet (XUV) transient absorption spectroscopy has emerged as a sensitive tool for mapping the real-time structural and electronic evolution of molecules. Here, attosecond XUV transient absorption is used to track dynamics in the A-band of methyl iodide (CH3I). Gaseous CH3I molecules are excited to the A-band by a UV pump (277 nm, ∼20 fs) and probed by attosecond XUV pulses targeting iodine I(4d) core-to-valence transitions. Owing to the excellent temporal resolution of the technique, passage through a conical intersection is mapped through spectral signatures of nonadiabatic wave packet bifurcation observed to occur at 15 ± 4 fs following UV photoexcitation. The observed XUV signatures and time dynamics are in agreement with previous simulations [H. Wang, M. Odelius, and D. Prendergast, J. Chem. Phys. 151, 124106 (2019)]. Due to the short duration of the UV pump pulse, coherent vibrational motion in the CH3I ground state along the C-I stretch mode (538 ± 7 cm-1) launched by resonant impulsive stimulated Raman scattering and dynamics in multiphoton excited states of CH3I are also detected.
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Affiliation(s)
- Kristina F Chang
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Han Wang
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Sonia M Poullain
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Madrid 28040, Spain
| | - David Prendergast
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Stephen R Leone
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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2
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Loh ZH. Studies of Ultrafast Molecular Dynamics by Femtosecond Extreme Ultraviolet Absorption Spectroscopy. CHEM LETT 2021. [DOI: 10.1246/cl.200940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
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3
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Revealing electronic state-switching at conical intersections in alkyl iodides by ultrafast XUV transient absorption spectroscopy. Nat Commun 2020; 11:4042. [PMID: 32788648 PMCID: PMC7423985 DOI: 10.1038/s41467-020-17745-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/06/2020] [Indexed: 11/11/2022] Open
Abstract
Conical intersections between electronic states often dictate the chemistry of photoexcited molecules. Recently developed sources of ultrashort extreme ultraviolet (XUV) pulses tuned to element-specific transitions in molecules allow for the unambiguous detection of electronic state-switching at a conical intersection. Here, the fragmentation of photoexcited iso-propyl iodide and tert-butyl iodide molecules (i-C3H7I and t-C4H9I) through a conical intersection between 3Q0/1Q1 spin–orbit states is revealed by ultrafast XUV transient absorption measuring iodine 4d core-to-valence transitions. The electronic state-sensitivity of the technique allows for a complete mapping of molecular dissociation from photoexcitation to photoproducts. In both molecules, the sub-100 fs transfer of a photoexcited wave packet from the 3Q0 state into the 1Q1 state at the conical intersection is captured. The results show how differences in the electronic state-switching of the wave packet in i-C3H7I and t-C4H9I directly lead to differences in the photoproduct branching ratio of the two systems. The reaction trajectories of photoexcited molecules may involve transitions through conical intersections, which are ubiquitous in nature but challenging to characterize. Here the authors provide a complete mapping of molecular dissociation of two model alkyl halides by ultrafast XUV transient absorption.
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Schubert K, Guda AA, Mertens K, Schunck JO, Schippers S, Müller A, Bari S, Klumpp S, Martins M. Absorption spectra at the iodine 3d ionisation threshold following the CH xI + (x = 0-3) cation sequence. Phys Chem Chem Phys 2019; 21:25415-25424. [PMID: 31710320 DOI: 10.1039/c9cp04640b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Yields of atomic iodine Iq+ (q≥ 2) fragments resulting from photoexcitation and photoionisation of the target cations CHxI+ (x = 0-3) have been measured in the photon-energy range 610 eV to 670 eV, which comprises the threshold for iodine 3d ionisation. The measured ion-yield spectra show two strong and broad resonance features due to the excitation of the 3d3/2,5/2 electrons into εf states similar to atomic iodine. In the 3d pre-edge range, electrons are excited into molecular orbitals consisting of iodine, carbon, and hydrogen atomic orbitals. These transitions have been identified by comparison with literature data and by simulations using time-dependent density functional theory (TDDFT) with the KMLYP functional. The ion-yield spectrum for CH3I+ resembles the spectrum of IH+ [Klumpp et al., Phys. Rev. A, 2018, 97, 033401] because the highest occupied molecular orbitals (HOMO) of the H and CH3 fragments both contain a single vacancy, only. For the molecular cations with higher number of vacancies in the valence molecular orbitals CHxI+ (x = 0-2), a stronger hybridisation of the molecular orbitals occurs between the organic fragment and the iodine resulting in a change of bonding from a single σ bond in CH3I+ to a triple bond including two π orbitals in CI+. This is reflected in the resonance energies of the observed absorption lines below the iodine 3d excitation threshold.
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Affiliation(s)
- Kaja Schubert
- Department Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany. and Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Alexander A Guda
- The Smart Materials Research Institute, Southern Federal University, Sladkova 178/24, 344090 Rostov-on-Don, Russia
| | - Karolin Mertens
- Department Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
| | - Jan O Schunck
- Department Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany. and Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Stefan Schippers
- Justus-Liebig-Universität Gießen, I. Physikalisches Institut, Heinrich-Buff-Ring 16, 35392 Gießen, Germany
| | - Alfred Müller
- Justus-Liebig-Universität Gießen, Institut für Atom- und Molekülphysik, Leihgesterner Weg 217, 35392 Gießen, Germany
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Stephan Klumpp
- Department Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany. and Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Michael Martins
- Department Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
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Geneaux R, Marroux HJB, Guggenmos A, Neumark DM, Leone SR. Transient absorption spectroscopy using high harmonic generation: a review of ultrafast X-ray dynamics in molecules and solids. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2019; 377:20170463. [PMID: 30929624 PMCID: PMC6452051 DOI: 10.1098/rsta.2017.0463] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/27/2018] [Indexed: 05/07/2023]
Abstract
Attosecond science opened the door to observing nuclear and electronic dynamics in real time and has begun to expand beyond its traditional grounds. Among several spectroscopic techniques, X-ray transient absorption spectroscopy has become key in understanding matter on ultrafast time scales. In this review, we illustrate the capabilities of this unique tool through a number of iconic experiments. We outline how coherent broadband X-ray radiation, emitted in high-harmonic generation, can be used to follow dynamics in increasingly complex systems. Experiments performed in both molecules and solids are discussed at length, on time scales ranging from attoseconds to picoseconds, and in perturbative or strong-field excitation regimes. This article is part of the theme issue 'Measurement of ultrafast electronic and structural dynamics with X-rays'.
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Affiliation(s)
- Romain Geneaux
- Department of Chemistry, University of California, Berkeley 94720, CA, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720, CA, USA
| | - Hugo J. B. Marroux
- Department of Chemistry, University of California, Berkeley 94720, CA, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720, CA, USA
| | - Alexander Guggenmos
- Department of Chemistry, University of California, Berkeley 94720, CA, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720, CA, USA
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley 94720, CA, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720, CA, USA
| | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley 94720, CA, USA
- Department of Physics, University of California, Berkeley 94720, CA, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley 94720, CA, USA
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Bhattacherjee A, Leone SR. Ultrafast X-ray Transient Absorption Spectroscopy of Gas-Phase Photochemical Reactions: A New Universal Probe of Photoinduced Molecular Dynamics. Acc Chem Res 2018; 51:3203-3211. [PMID: 30462481 DOI: 10.1021/acs.accounts.8b00462] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Time-resolved spectroscopic investigations of light-induced chemical reactions with universal detection capitalize recently on single-photon molecular probing using laser pulses in the extreme ultraviolet or X-ray regimes. Direct and simultaneous mappings of the time-evolving populations of ground-state reactants, Franck-Condon (FC) and transition state regions, excited-state intermediates and conical intersections (CI), and photoproducts in photochemical reactions utilize probe pulses that are broadband and energy-tunable. The limits on temporal resolution are set by the transit- or dwell-time of the photoexcited molecules at specific locations on the potential energy surface, typically ranging from a few femtoseconds to several hundred picoseconds. Femtosecond high-harmonic generation (HHG) meets the stringent demands for a universal spectroscopic probe of large regions of the intramolecular phase-space in unimolecular photochemical reactions. Extreme-ultraviolet and soft X-ray pulses generated in this manner with few-femtosecond or sub-femtosecond durations have enormous bandwidths, allowing the probing of many elements simultaneously through excitation or ionization of core-electrons, creating molecular movies that shed light on entire photochemical pathways. At free electron lasers (FELs), powerful investigations are also possible, recognizing their higher flux and tunability but more limited bandwidths. Femtosecond time-resolved X-ray transient absorption spectroscopy, in particular, is a valuable universal probe of reaction pathways that maps changes via the fingerprint core-to-valence resonances. The particular power of this method over valence-ionization probes lies in its unmatched element and chemical-site specificities. The elements carbon, nitrogen, and oxygen constitute the fundamental building blocks of life; photochemical reactions involving these elements are ubiquitous, diverse, and manifold. However, table-top HHG sources in the "water-window" region (280-550 eV), which encompasses the 1s-absorption edges of carbon (284 eV), nitrogen (410 eV), and oxygen (543 eV), are far from abundant or trivial. Recent breakthroughs in the laboratory have embraced this region by using long driving-wavelength optical parametric amplifiers coupled with differentially pumped high-pressure gas source cells. This has opened avenues to study a host of photochemical reactions in organic molecules using femtosecond time-resolved transient absorption at the carbon K-edge. In this Account, we summarize recent efforts to deploy a table-top carbon K-edge source to obtain crucial chemical insights into ultrafast, ultraviolet-induced chemical reactions involving ring-opening, nonadiabatic excited-state relaxation, bond dissociation and radical formation. The X-ray probe provides a direct spectroscopic viewport into the electronic characters and configurations of the valence electronic states through spectroscopic core-level transitions into the frontier molecular orbitals of the photoexcited molecules, laying fertile ground for the real-time mapping of the evolving valence electronic structure. The profound detail and mechanistic insights emerging from the pioneering experiments at the carbon K-edge are outlined here. Comparisons of the experimental methodology with other techniques employed to study similar reactions are drawn, where applicable and relevant. We show that femtosecond time-resolved X-ray transient absorption spectroscopy blazes a new trail in the study of nonadiabatic molecular dynamics. Despite table-top implementations being largely in their infancy, future chemical applications of the technique will set the stage for widely applicable, universal probes of photoinduced molecular dynamics with unprecedented temporal resolution.
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Affiliation(s)
- Aditi Bhattacherjee
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
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Wei Z, Tian L, Li J, Lu Y, Yang M, Loh ZH. Tracking Ultrafast Bond Dissociation Dynamics at 0.1 Å Resolution by Femtosecond Extreme Ultraviolet Absorption Spectroscopy. J Phys Chem Lett 2018; 9:5742-5747. [PMID: 30212632 DOI: 10.1021/acs.jpclett.8b02547] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Visualizing the real-time dissociation of chemical bonds represents a challenge in the study of ultrafast molecular dynamics due to the simultaneous need for sub-angstrom spatial and femtosecond temporal resolution. Here, we follow the C-I dissociation dynamics of strong-field-ionized 2-iodopropane (2-C3H7I) with femtosecond extreme ultraviolet (XUV) absorption spectroscopy. By probing the iodine 4 d core-level absorption, we resolve a continuous XUV spectral shift on the sub-100 fs time scale that accompanies the dissociation of the 2-C3H7I+ spin-orbit-excited 2 E1/2 state to yield atomic I in the 2 P3/2 state. In combination with ab initio calculations of the C-I distance-dependent XUV transition energy, we reconstruct the temporal evolution of the C-I distance from the Franck-Condon region to the asymptotic region with 10 fs and 0.1 Å resolution. The C-I bond elongation appears to couple to coherent vibrational motion along the HC(CH3)2 umbrella mode of the 2-C3H7+ fragment, whose effect on the I 4 d XUV transition even at C-I distances of 3.5 Å points to the long-range nature of XUV absorption probing. Our results suggest that femtosecond XUV absorption spectroscopy, in combination with ab initio simulations of XUV transition energies, can be used to resolve the ultrafast structural dynamics of large polyatomic molecules.
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Affiliation(s)
- Zhengrong Wei
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
| | - Li Tian
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics , Chinese Academy of Sciences , Wuhan 430071 , China
| | - Jialin Li
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
| | - Yunpeng Lu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
| | - Minghui Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics , Chinese Academy of Sciences , Wuhan 430071 , China
| | - Zhi-Heng Loh
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , Singapore 637371
- Centre for Optical Fibre Technology, The Photonics Institute , Nanyang Technological University , Singapore 639798
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Bhattacherjee A, Schnorr K, Oesterling S, Yang Z, Xue T, de Vivie-Riedle R, Leone SR. Photoinduced Heterocyclic Ring Opening of Furfural: Distinct Open-Chain Product Identification by Ultrafast X-ray Transient Absorption Spectroscopy. J Am Chem Soc 2018; 140:12538-12544. [DOI: 10.1021/jacs.8b07155] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Aditi Bhattacherjee
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Kirsten Schnorr
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Sven Oesterling
- Department of Chemistry, Ludwig-Maximilians-Universität München, München 81377, Germany
| | - Zheyue Yang
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Tian Xue
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | | | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Physics, University of California, Berkeley, California 94720, United States
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Bhattacherjee A, Pemmaraju CD, Schnorr K, Attar AR, Leone SR. Ultrafast Intersystem Crossing in Acetylacetone via Femtosecond X-ray Transient Absorption at the Carbon K-Edge. J Am Chem Soc 2017; 139:16576-16583. [DOI: 10.1021/jacs.7b07532] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Aditi Bhattacherjee
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Chaitanya Das Pemmaraju
- Theory
Institute for Materials and Energy Spectroscopies, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Kirsten Schnorr
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew R. Attar
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Stephen R. Leone
- Department
of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical
Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department
of Physics, University of California, Berkeley, California 94720, United States
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Drescher L, Galbraith MCE, Reitsma G, Dura J, Zhavoronkov N, Patchkovskii S, Vrakking MJJ, Mikosch J. Communication: XUV transient absorption spectroscopy of iodomethane and iodobenzene photodissociation. J Chem Phys 2016; 145:011101. [DOI: 10.1063/1.4955212] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bhattacherjee A, Attar AR, Leone SR. Transition state region in the A-Band photodissociation of allyl iodide—A femtosecond extreme ultraviolet transient absorption study. J Chem Phys 2016; 144:124311. [DOI: 10.1063/1.4944930] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Aditi Bhattacherjee
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Andrew R. Attar
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Stephen R. Leone
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
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