1
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Cachón J, Recio P, Sorribes D, Marggi Poullain S, Rubio-Lago L, Bañares L. Structural Effects on the Energy Disposal and Atomic Photofragment Alignment for the Photodissociation of Alkyl Iodides at Excitation Wavelengths of 254 and 268 nm. J Phys Chem A 2024. [PMID: 39298671 DOI: 10.1021/acs.jpca.4c02217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2024]
Abstract
This work represents a step forward in the understanding of the widely studied photodynamics of alkyl iodides in the first absorption band. Ultraviolet (UV) photodissociation of several alkyl iodides (RI), specifically, a series of linear and ramified molecules with R = CnH2n+1, n = 1-4, at excitation wavelengths of 254 and 268 nm, which correspond to the maximum of the first absorption A-band, has been studied by combining resonance-enhanced multiphoton ionization (REMPI) detection of atomic photofragments I(2P3/2) and I*(2P1/2) and of pulsed slice imaging. Detailed examination of the total translational energy distributions of both atomic photofragments has been combined with stereodynamical information on the process obtained from the anisotropy β and alignment a02(∥) and Re[a12(∥, ⊥)] parameters to provide a description of the role played by the molecular structure of alkyl iodides in adiabatic and, especially, in nonadiabatic photodissociation dynamics through conical intersections or avoided crossings. The present results suggest that the linear structures couple more efficiently with the pure C-I reaction coordinate, whereas for the branched structures, the coupling with additional vibrational (bending) modes gains importance, showing the dissociation process a multidimensional character. In addition, a large degree of cofragment rotational alignment has been found for the small linear CH3I and C2H5I and, unexpectedly, for the branched t-C4H9I (C3v symmetry), whereas the rest of the alkyl iodides show low alignment parameters.
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Affiliation(s)
- Javier Cachón
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Pedro Recio
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - David Sorribes
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Sonia Marggi Poullain
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Luis Rubio-Lago
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanoscience), C/Faraday, 9, 28049 Madrid, Spain
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2
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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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3
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Razmus WO, Allum F, Harries J, Kumagai Y, Nagaya K, Bhattacharyya S, Britton M, Brouard M, Bucksbaum PH, Cheung K, Crane SW, Fushitani M, Gabalski I, Gejo T, Ghrist A, Heathcote D, Hikosaka Y, Hishikawa A, Hockett P, Jones E, Kukk E, Iwayama H, Lam HVS, McManus JW, Milesevic D, Mikosch J, Minemoto S, Niozu A, Orr-Ewing AJ, Owada S, Rolles D, Rudenko A, Townsend D, Ueda K, Unwin J, Vallance C, Venkatachalam A, Wada SI, Walmsley T, Warne EM, Woodhouse JL, Burt M, Ashfold MNR, Minns RS, Forbes R. Exploring the ultrafast and isomer-dependent photodissociation of iodothiophenes via site-selective ionization. Phys Chem Chem Phys 2024; 26:12725-12737. [PMID: 38616653 DOI: 10.1039/d3cp06079a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
C-I bond extension and fission following ultraviolet (UV, 262 nm) photoexcitation of 2- and 3-iodothiophene is studied using ultrafast time-resolved extreme ultraviolet (XUV) ionization in conjunction with velocity map ion imaging. The photoexcited molecules and eventual I atom products are probed by site-selective ionization at the I 4d edge using intense XUV pulses, which induce multiple charges initially localized to the iodine atom. At C-I separations below the critical distance for charge transfer (CT), charge can redistribute around the molecule leading to Coulomb explosion and charged fragments with high kinetic energy. At greater C-I separations, beyond the critical distance, CT is no longer possible and the measured kinetic energies of the charged iodine atoms report on the neutral dissociation process. The time and momentum resolved measurements allow determination of the timescales and the respective product momentum and kinetic energy distributions for both isomers, which are interpreted in terms of rival 'direct' and 'indirect' dissociation pathways. The measurements are compared with a classical over the barrier model, which reveals that the onset of the indirect dissociation process is delayed by ∼1 ps relative to the direct process. The kinetics of the two processes show no discernible difference between the two parent isomers, but the branching between the direct and indirect dissociation channels and the respective product momentum distributions show isomer dependencies. The greater relative yield of indirect dissociation products from 262 nm photolysis of 3-iodothiophene (cf. 2-iodothiophene) is attributed to the different partial cross-sections for (ring-centred) π∗ ← π and (C-I bond localized) σ∗ ← (n/π) excitation in the respective parent isomers.
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Affiliation(s)
- Weronika O Razmus
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | - Felix Allum
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
- PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
| | | | - Yoshiaki Kumagai
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Kiyonobu Nagaya
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Surjendu Bhattacharyya
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Mathew Britton
- PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Mark Brouard
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Philip H Bucksbaum
- PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Kieran Cheung
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Stuart W Crane
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Mizuho Fushitani
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
| | - Ian Gabalski
- PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Tatsuo Gejo
- Graduate School of Material Science, University of Hyogo, Kuoto 3-2-1, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Aaron Ghrist
- PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - David Heathcote
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Yasumasa Hikosaka
- Institute of Liberal Arts and Sciences, University of Toyama, Toyama 930-0194, Japan
| | - Akiyoshi Hishikawa
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
- Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi 464-8602, Japan
| | - Paul Hockett
- National Research Council of Canada, 100 Sussex Dr, Ottawa, ON K1A 0R6, Canada
| | - Ellen Jones
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Edwin Kukk
- Department of Physics and Astronomy, University of Turku, FI-20014 Turku, Finland
| | | | - Huynh V S Lam
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Joseph W McManus
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Dennis Milesevic
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Jochen Mikosch
- Department of Physics, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Shinichirou Minemoto
- Department of Physics, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Akinobu Niozu
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Shigeki Owada
- RIKEN SPring-8 Center, Sayo, Hyogo, 679-5148, Japan
- Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Daniel Rolles
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Artem Rudenko
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Dave Townsend
- Institute of Photonics and Quantum Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Kiyoshi Ueda
- Department of Chemistry, Tohoku University, Sendai 980-8578, Japan
- Department of Condensed Matter Physics and Photon Science, School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - James Unwin
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Claire Vallance
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Anbu Venkatachalam
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA
| | - Shin-Ichi Wada
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Tiffany Walmsley
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Emily M Warne
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Joanne L Woodhouse
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | - Michael Burt
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Michael N R Ashfold
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Russell S Minns
- School of Chemistry, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | - Ruaridh Forbes
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
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4
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González-Vázquez J, García GA, Chicharro DV, Bañares L, Poullain SM. Evidencing an elusive conical intersection in the dissociative photoionization of methyl iodide. Chem Sci 2024; 15:3203-3213. [PMID: 38425510 PMCID: PMC10901492 DOI: 10.1039/d3sc04065h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 12/23/2023] [Indexed: 03/02/2024] Open
Abstract
The valence-shell dissociative photoionization of methyl iodide (CH3I) is studied using double imaging photoelectron photoion coincidence (i2 PEPICO) spectroscopy in combination with highly-tunable synchrotron radiation from synchrotron SOLEIL. The experimental results are complemented by new high-level ab initio calculations of the potential energy curves of the relevant electronic states of the methyl iodide cation (CH3I+). An elusive conical intersection is found to mediate internal conversion from the initially populated first excited state, CH3I+(Ã2A1), into the ground cationic state, leading to the formation of methyl ions (CH3+). The reported threshold photoelectron spectrum for CH3+ reveals that the ν5 scissors vibrational mode promotes the access to this conical intersection and hence, the transfer of population. An intramolecular charge transfer takes place simultaneously, prior to dissociation. Upon photoionization into the second excited cationic state, CH3I+(B̃2E), a predissociative mechanism is shown to lead to the formation of atomic I+.
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Affiliation(s)
- Jesús González-Vázquez
- Departamento de Química, Facultad de Ciencias, Universidad Autónoma de Madrid Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid 28049 Madrid Spain
| | - Gustavo A García
- Synchrotron SOLEIL L'Orme des Merisiers, St. Aubin, BP 48 91192 Gif-sur-Yvette France
| | - David V Chicharro
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid 28040 Madrid Spain
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid 28040 Madrid Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience) Cantoblanco 28049 Madrid Spain
| | - Sonia Marggi Poullain
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid 28040 Madrid Spain
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5
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Toulson BW, Hait D, Faccialà D, Neumark DM, Leone SR, Head-Gordon M, Gessner O. Probing C-I bond fission in the UV photochemistry of 2-iodothiophene with core-to-valence transient absorption spectroscopy. J Chem Phys 2023; 159:034304. [PMID: 37466229 DOI: 10.1063/5.0151629] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 06/29/2023] [Indexed: 07/20/2023] Open
Abstract
The UV photochemistry of small heteroaromatic molecules serves as a testbed for understanding fundamental photo-induced chemical transformations in moderately complex compounds, including isomerization, ring-opening, and molecular dissociation. Here, a combined experimental-theoretical study of 268 nm UV light-induced dynamics in 2-iodothiophene (C4H3IS) is performed. The dynamics are experimentally monitored with a femtosecond extreme ultraviolet (XUV) probe that measures iodine N-edge 4d core-to-valence transitions. Experiments are complemented by density functional theory calculations of both the pump-pulse induced valence excitations and the XUV probe-induced core-to-valence transitions. Possible intramolecular relaxation dynamics are investigated by ab initio molecular dynamics simulations. Gradual absorption changes up to ∼0.5 to 1 ps after excitation are observed for both the parent molecular species and emerging iodine fragments, with the latter appearing with a characteristic rise time of 160 ± 30 fs. Comparison of spectral intensities and energies with the calculations identifies an iodine dissociation pathway initiated by a predominant π → π* excitation. In contrast, initial excitation to a nearby n⟂ → σ* state appears unlikely based on a significantly smaller oscillator strength and the absence of any corresponding XUV absorption signatures. Excitation to the π → π* state is followed by contraction of the C-I bond, enabling a nonadiabatic transition to a dissociative π→σC-I* state. For the subsequent fragmentation, a relatively narrow bond-length region along the C-I stretch coordinate between 230 and 280 pm is identified, where the transition between the parent molecule and the thienyl radical + iodine atom products becomes prominent in the XUV spectrum due to rapid localization of two singly occupied molecular orbitals on the two fragments.
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Affiliation(s)
- Benjamin W Toulson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Diptarka Hait
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Davide Faccialà
- CNR-Istituto di Fotonica e Nanotecnologie (CNR-IFN), 20133 Milano, Italy
| | - Daniel M Neumark
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Stephen R Leone
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Martin Head-Gordon
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
| | - Oliver Gessner
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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6
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Heald LF, Gosman RS, Rotteger CH, Jarman CK, Sayres SG. Nonadiabatic Photodissociation and Dehydrogenation Dynamics of n-Butyl Bromide Following p-Rydberg Excitation. J Phys Chem Lett 2023:6278-6285. [PMID: 37399455 DOI: 10.1021/acs.jpclett.3c01438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
Femtosecond time-resolved mass spectrometry, correlation mapping, and density functional theory calculations are employed to reveal the mechanism of C═C and C≡C formation (and related H2 production) following excitation to the p-Rydberg states of n-butyl bromide. Ultrafast pump-probe mass spectrometry shows that nonadiabatic relaxation operates as a multistep process reaching an intermediate state within ∼500 fs followed by relaxation to a final state within 10 ps of photoexcitation. Absorption of three ultraviolet photons accesses the dense p-Rydberg state manifold, which is further excited by the probe beam for C─C bond dissociation and dehydrogenation reactions. Rapid internal conversion deactivates the dehydrogenation pathways, while activating carbon backbone dissociation pathways. Thus, unsaturated carbon fragments decay with the lifetime of p-Rydberg (∼500 fs), matching the growth recorded in saturated hydrocarbon fragments. The saturated hydrocarbon signals subsequently decay on the picosecond time scale as the molecule relaxes below the Rydberg states and into halogen release channels.
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Affiliation(s)
- Lauren F Heald
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Robert S Gosman
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Chase H Rotteger
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Carter K Jarman
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
| | - Scott G Sayres
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287, United States
- Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona 85287, United States
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7
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Ling F, Wang Y, Cao L, Wei J, Liu D, Luo Z, Long J, Wang P, Song X, Zhang S. Structural dynamics upon photoinduced charge transfer in N,N,N',N'-tetramethylmethylenediamine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023; 293:122524. [PMID: 36821936 DOI: 10.1016/j.saa.2023.122524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/13/2023] [Accepted: 02/17/2023] [Indexed: 06/18/2023]
Abstract
The ultrafast structural motion linked to the charge transfer process in Rydberg excited N,N,N',N'-tetramethylmethylenediamine (TMMDA) has been monitored in real time using femtosecond time-resolved photoelectron imaging coupled with quantum chemical calculations. Optical excitation to the 3 s Rydberg state initially populates the charge on one of the two amine groups, resulting in a charge-localized structure in the Franck-Condon (FC) region. As the wavepacket evolves on the 3 s potential surface, the molecular geometry changes with time, leading to the corresponding variation in the charge distribution. The ensuing structural evolution yields two distinct conformers GG+ and TT+ (see text for nomenclature), both with the charge delocalized between the two nitrogen atoms. By virtue of the sensitivity of the Rydberg electron binding energy (BE) on the nuclear geometry, the time-dependent BE spectrum offers an intuitive mapping of the charge transfer reaction that leads from the initially prepared charge-localized GG-FC structure to the fully charge-delocalized GG+ and TT+ structures. Complementary computations provide evidence that through-space interaction is responsible for the charge delocalization in the GG+ and TT+ structures.
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Affiliation(s)
- Fengzi Ling
- School of Science, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China; Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Yanmei Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Ling Cao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Jie Wei
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Dejun Liu
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Zhigao Luo
- School of Science, Shenzhen Campus of Sun Yat-sen University, Shenzhen 518107, China
| | - Jinyou Long
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Pengfei Wang
- Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China; Key Laboratory of In-Fiber Integrated Optics, Ministry Education of China, Harbin Engineering University, Harbin 150001, China.
| | - Xinli Song
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Song Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
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8
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Heald LF, Loftus CL, Gosman RS, Sayres SG. Ion-Pair Formation in n-Butyl Bromide through 5p Ryberg State Predissociation. J Phys Chem A 2022; 126:9651-9657. [PMID: 36528811 DOI: 10.1021/acs.jpca.2c06777] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The ultrafast photodynamics of n-butyl bromide are explored with femtosecond time-resolved mass spectrometry. Absorption of two UV (400 nm) pump photons induces the direct dissociation of the C-Br bond from the A state within 160 fs. Absorption of three UV pump photons excites the molecule into the 5p Rydberg state which undergoes several relaxation pathways including to the ion-pair state. Relaxation to the ion-pair state is tracked through the transient of the C4H9+ fragment and suggests an E state lifetime of 10.8 ± 0.5 ps, in close agreement with the tunneling time of smaller molecules. Predissociation from the 5p Rydberg states leads to the β-elimination of H-Br and formation of C4H8+ within 3.0 ± 0.25 ps. A portion of the excited parent molecule avoids the ion-pair formation and instead relaxes through the Rydberg excited state manifold into the D state within 30.2 ± 0.21 ps.
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Affiliation(s)
- Lauren F Heald
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
| | - Colleen L Loftus
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
| | - Robert S Gosman
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
| | - Scott G Sayres
- School of Molecular Sciences, Arizona State University, Tempe, Arizona85287, United States.,Biodesign Center for Applied Structural Discovery, Arizona State University, Tempe, Arizona85287, United States
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9
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Gabalski I, Sere M, Acheson K, Allum F, Boutet S, Dixit G, Forbes R, Glownia JM, Goff N, Hegazy K, Howard AJ, Liang M, Minitti MP, Minns RS, Natan A, Peard N, Rasmus WO, Sension RJ, Ware MR, Weber PM, Werby N, Wolf TJA, Kirrander A, Bucksbaum PH. Transient vibration and product formation of photoexcited CS 2 measured by time-resolved x-ray scattering. J Chem Phys 2022; 157:164305. [PMID: 36319419 PMCID: PMC9625835 DOI: 10.1063/5.0113079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/03/2022] [Indexed: 11/14/2022] Open
Abstract
We have observed details of the internal motion and dissociation channels in photoexcited carbon disulfide (CS2) using time-resolved x-ray scattering (TRXS). Photoexcitation of gas-phase CS2 with a 200 nm laser pulse launches oscillatory bending and stretching motion, leading to dissociation of atomic sulfur in under a picosecond. During the first 300 fs following excitation, we observe significant changes in the vibrational frequency as well as some dissociation of the C-S bond, leading to atomic sulfur in the both 1D and 3P states. Beyond 1400 fs, the dissociation is consistent with primarily 3P atomic sulfur dissociation. This channel-resolved measurement of the dissociation time is based on our analysis of the time-windowed dissociation radial velocity distribution, which is measured using the temporal Fourier transform of the TRXS data aided by a Hough transform that extracts the slopes of linear features in an image. The relative strength of the two dissociation channels reflects both their branching ratio and differences in the spread of their dissociation times. Measuring the time-resolved dissociation radial velocity distribution aids the resolution of discrepancies between models for dissociation proposed by prior photoelectron spectroscopy work.
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Affiliation(s)
- Ian Gabalski
- Author to whom correspondence should be addressed:
| | | | - Kyle Acheson
- School of Chemistry, University of Edinburgh, Edinburgh EH8 9YL, United Kingdom
| | | | - Sébastien Boutet
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Gopal Dixit
- Department of Physics, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
| | | | - James M. Glownia
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Nathan Goff
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | | | | | - Mengning Liang
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Michael P. Minitti
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Russell S. Minns
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Adi Natan
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Nolan Peard
- Department of Applied Physics, Stanford University, Stanford, California 94305, USA
| | - Weronika O. Rasmus
- School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom
| | - Roseanne J. Sension
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Matthew R. Ware
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Peter M. Weber
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
| | | | | | - Adam Kirrander
- Physical and Theoretical Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, OX1 3QX Oxford, United Kingdom
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10
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McManus JW, Walmsley T, Nagaya K, Harries JR, Kumagai Y, Iwayama H, Ashfold MNR, Britton M, Bucksbaum PH, Downes-Ward B, Driver T, Heathcote D, Hockett P, Howard AJ, Kukk E, Lee JWL, Liu Y, Milesevic D, Minns RS, Niozu A, Niskanen J, Orr-Ewing AJ, Owada S, Rolles D, Robertson PA, Rudenko A, Ueda K, Unwin J, Vallance C, Burt M, Brouard M, Forbes R, Allum F. Disentangling sequential and concerted fragmentations of molecular polycations with covariant native frame analysis. Phys Chem Chem Phys 2022; 24:22699-22709. [PMID: 36106844 DOI: 10.1039/d2cp03029b] [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
We present results from an experimental ion imaging study into the fragmentation dynamics of 1-iodopropane and 2-iodopropane following interaction with extreme ultraviolet intense femtosecond laser pulses with a photon energy of 95 eV. Using covariance imaging analysis, a range of observed fragmentation pathways of the resulting polycations can be isolated and interrogated in detail at relatively high ion count rates (∼12 ions shot-1). By incorporating the recently developed native frames analysis approach into the three-dimensional covariance imaging procedure, contributions from three-body concerted and sequential fragmentation mechanisms can be isolated. The angular distribution of the fragment ions is much more complex than in previously reported studies for triatomic polycations, and differs substantially between the two isomeric species. With support of simple simulations of the dissociation channels of interest, detailed physical insights into the fragmentation dynamics are obtained, including how the initial dissociation step in a sequential mechanism influences rovibrational dynamics in the metastable intermediate ion and how signatures of this nuclear motion manifest in the measured signals.
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Affiliation(s)
- Joseph W McManus
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Tiffany Walmsley
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Kiyonobu Nagaya
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | | | - Yoshiaki Kumagai
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo 184-8588, Japan
| | - Hiroshi Iwayama
- UVSOR Synchrotron Facility, Institute for Molecular Science, Okazaki 444-8585, Japan
| | - Michael N R Ashfold
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Mathew Britton
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Philip H Bucksbaum
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Briony Downes-Ward
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Taran Driver
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - David Heathcote
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Paul Hockett
- National Research Council of Canada, 100 Sussex Dr., Ottawa, ON K1A 0R6, Canada
| | - Andrew J Howard
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Edwin Kukk
- Department of Physics and Astronomy, University of Turku, Turku, FI-20014, Finland
| | - Jason W L Lee
- Deutsches Elektronen-Synchrotron (DESY), Notkestraße 85, 22607 Hamburg, Germany
| | - Yusong Liu
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Dennis Milesevic
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Russell S Minns
- Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK
| | - Akinobu Niozu
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Johannes Niskanen
- Department of Physics and Astronomy, University of Turku, Turku, FI-20014, Finland
| | - Andrew J Orr-Ewing
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Shigeki Owada
- RIKEN SPring-8 Center, Sayo, Hyogo, 679-5148, Japan.,Japan Synchrotron Radiation Research Institute, Hyogo, Japan
| | - Daniel Rolles
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS, 66506, USA
| | - Patrick A Robertson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Artem Rudenko
- J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, KS, 66506, USA
| | - Kiyoshi Ueda
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, 980-8577, Japan
| | - James Unwin
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Claire Vallance
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Michael Burt
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Mark Brouard
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK
| | - Ruaridh Forbes
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
| | - Felix Allum
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, UK.,Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.,Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
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11
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Svoboda V, Ram NB, Baykusheva D, Zindel D, Waters MDJ, Spenger B, Ochsner M, Herburger H, Stohner J, Wörner HJ. Femtosecond photoelectron circular dichroism of chemical reactions. SCIENCE ADVANCES 2022; 8:eabq2811. [PMID: 35857523 PMCID: PMC9286499 DOI: 10.1126/sciadv.abq2811] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Understanding the chirality of molecular reaction pathways is essential for a broad range of fundamental and applied sciences. However, the current ability to probe chirality on the time scale of primary processes underlying chemical reactions remains very limited. Here, we demonstrate time-resolved photoelectron circular dichroism (TRPECD) with ultrashort circularly polarized vacuum-ultraviolet (VUV) pulses from a tabletop source. We demonstrate the capabilities of VUV-TRPECD by resolving the chirality changes in time during the photodissociation of atomic iodine from two chiral molecules. We identify several general key features of TRPECD, which include the ability to probe dynamical chirality along the complete photochemical reaction path, the sensitivity to the local chirality of the evolving scattering potential, and the influence of electron scattering off dissociating photofragments. Our results are interpreted by comparison with high-level ab-initio calculations of transient PECDs from molecular photoionization calculations. Our experimental and theoretical techniques define a general approach to femtochirality.
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Affiliation(s)
- Vít Svoboda
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Niraghatam Bhargava Ram
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
- Department of Physics, Indian Institute of Science Education and Research–Bhopal, Bhauri, Bhopal 462066, India
| | | | - Daniel Zindel
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Max D. J. Waters
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Benjamin Spenger
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Wädenswil 8820, Switzerland
| | - Manuel Ochsner
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Holger Herburger
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
| | - Jürgen Stohner
- Institute of Chemistry and Biotechnology, Zurich University of Applied Sciences, Wädenswil 8820, Switzerland
| | - Hans Jakob Wörner
- Laboratory of Physical Chemistry, ETH Zürich, 8093 Zürich, Switzerland
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12
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Allum F, Music V, Inhester L, Boll R, Erk B, Schmidt P, Baumann TM, Brenner G, Burt M, Demekhin PV, Dörner S, Ehresmann A, Galler A, Grychtol P, Heathcote D, Kargin D, Larsson M, Lee JWL, Li Z, Manschwetus B, Marder L, Mason R, Meyer M, Otto H, Passow C, Pietschnig R, Ramm D, Schubert K, Schwob L, Thomas RD, Vallance C, Vidanović I, von Korff Schmising C, Wagner R, Walter P, Zhaunerchyk V, Rolles D, Bari S, Brouard M, Ilchen M. A localized view on molecular dissociation via electron-ion partial covariance. Commun Chem 2022; 5:42. [PMID: 36697752 PMCID: PMC9814695 DOI: 10.1038/s42004-022-00656-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 02/21/2022] [Indexed: 02/01/2023] Open
Abstract
Inner-shell photoelectron spectroscopy provides an element-specific probe of molecular structure, as core-electron binding energies are sensitive to the chemical environment. Short-wavelength femtosecond light sources, such as Free-Electron Lasers (FELs), even enable time-resolved site-specific investigations of molecular photochemistry. Here, we study the ultraviolet photodissociation of the prototypical chiral molecule 1-iodo-2-methylbutane, probed by extreme-ultraviolet (XUV) pulses from the Free-electron LASer in Hamburg (FLASH) through the ultrafast evolution of the iodine 4d binding energy. Methodologically, we employ electron-ion partial covariance imaging as a technique to isolate otherwise elusive features in a two-dimensional photoelectron spectrum arising from different photofragmentation pathways. The experimental and theoretical results for the time-resolved electron spectra of the 4d3/2 and 4d5/2 atomic and molecular levels that are disentangled by this method provide a key step towards studying structural and chemical changes from a specific spectator site.
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Affiliation(s)
- Felix Allum
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK.
- Stanford PULSE Institute, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA.
| | - Valerija Music
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
- European XFEL, Holzkoppel 4, 22869, Schenefeld, Germany
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Ludger Inhester
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
| | - Rebecca Boll
- European XFEL, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Benjamin Erk
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Philipp Schmidt
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
- European XFEL, Holzkoppel 4, 22869, Schenefeld, Germany
| | | | - Günter Brenner
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Michael Burt
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Philipp V Demekhin
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
| | - Simon Dörner
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Arno Ehresmann
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
| | | | | | - David Heathcote
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Denis Kargin
- Institut für Chemie, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
| | - Mats Larsson
- Stockholm University, AlbaNova University Center, 114 21, Stockholm, Sweden
| | - Jason W L Lee
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Zheng Li
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing, 100871, China
| | - Bastian Manschwetus
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Lutz Marder
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
| | - Robert Mason
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Michael Meyer
- European XFEL, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Huda Otto
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
| | - Christopher Passow
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Rudolf Pietschnig
- Institut für Chemie, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
| | - Daniel Ramm
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Kaja Schubert
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Lucas Schwob
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Richard D Thomas
- Stockholm University, AlbaNova University Center, 114 21, Stockholm, Sweden
| | - Claire Vallance
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Igor Vidanović
- Institut für Chemie, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany
| | | | - René Wagner
- European XFEL, Holzkoppel 4, 22869, Schenefeld, Germany
| | - Peter Walter
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA
| | | | - Daniel Rolles
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, 1228 Martin Luther King Jr. Dr., Manhattan, KS, 66506, USA
| | - Sadia Bari
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
| | - Mark Brouard
- The Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Markus Ilchen
- Institut für Physik und CINSaT, Universität Kassel, Heinrich-Plett-Straße 40, D-34132, Kassel, Germany.
- European XFEL, Holzkoppel 4, 22869, Schenefeld, Germany.
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
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13
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Chang KF, Wang H, Poullain SM, González-Vázquez J, Bañares L, Prendergast D, Neumark DM, Leone SR. Conical intersection and coherent vibrational dynamics in alkyl iodides captured by attosecond transient absorption spectroscopy. J Chem Phys 2022; 156:114304. [DOI: 10.1063/5.0086775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The photodissociation dynamics of alkyl iodides along the C–I bond are captured by attosecond extreme-ultraviolet (XUV) transient absorption spectroscopy employing resonant ∼20 fs UV pump pulses. The methodology of previous experiments on CH3I [Chang et al., J. Chem. Phys. 154, 234301 (2021)] is extended to the investigation of a C–I bond-breaking reaction in the dissociative A-band of C2H5I, i-C3H7I, and t-C4H9I. Probing iodine 4 d core-to-valence transitions in the XUV enables one to map wave packet bifurcation at a conical intersection in the A-band as well as coherent vibrations in the ground state of the parent molecules. Analysis of spectroscopic bifurcation signatures yields conical intersection crossing times of 15 ± 4 fs for CH3I, 14 ± 5 fs for C2H5I, and 24 ± 4 fs for i-C3H7I and t-C4H9I, respectively. Observations of coherent vibrations, resulting from a projection of A-band structural dynamics onto the ground state by resonant impulsive stimulated Raman scattering, indirectly reveal multimode C–I stretch and CCI bend vibrations in the A-bands of C2H5I, i-C3H7I, and t-C4H9I.
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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
| | - Jesús González-Vázquez
- Departamento de Química, Universidad Autónoma de Madrid, Madrid 28049, Spain
- Institute of Advanced Research on Chemistry, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, Madrid 28040, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Cantoblanco 28049, Madrid, Spain
| | - David Prendergast
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Daniel M. Neumark
- 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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14
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Jochim B, DeJesus L, Dantus M. Ultrafast disruptive probing: Simultaneously keeping track of tens of reaction pathways. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:033003. [PMID: 35365005 DOI: 10.1063/5.0084837] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/07/2022] [Indexed: 06/14/2023]
Abstract
Ultrafast science depends on different implementations of the well-known pump-probe method. Here, we provide a formal description of ultrafast disruptive probing, a method in which the probe pulse disrupts a transient species that may be a metastable ion or a transient state of matter. Disruptive probing has the advantage of allowing for simultaneous tracking of the yield of tens of different processes. Our presentation includes a numerical model and experimental data on multiple products resulting from the strong-field ionization of two different molecules, partially deuterated methanol and norbornene. The correlated enhancement and depletion signals between all the different fragmentation channels offer comprehensive information on photochemical reaction pathways. In combination with ion imaging and/or coincidence momentum imaging or as complementary to atom-specific probing or ultrafast diffraction methods, disruptive probing is a particularly powerful tool for the study of strong-field laser-matter interactions.
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Affiliation(s)
- Bethany Jochim
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Lindsey DeJesus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA
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15
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Nag P, Anand N, Vennapusa SR. Ultrafast nonadiabatic excited-state intramolecular proton transfer in 3-hydroxychromone: A surface hopping approach. J Chem Phys 2021; 155:094301. [PMID: 34496583 DOI: 10.1063/5.0060934] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We employ the ab initio molecular dynamics within the surface hopping method to explore the excited-state intramolecular proton transfer taking place on the coupled "bright" S1 (ππ*) and "dark" S2 (nπ*) states of 3-hydroxychromone. The nonadiabatic population transfer between these states via an accessible conical intersection would open up multiple proton transfer pathways. Our findings reveal the keto tautomer formation via S1 on a timescale similar to the O-H in-plane vibrational period (<100 fs). Structural analysis indicates that a few parameters of the five-membered proton transfer geometry that constitute the donor (hydroxyl) and acceptor (carbonyl) groups would be adequate to drive the enol to keto transformation. We also investigate the role of O-H in-plane and out-of-plane vibrational motions in the excited-state dynamics of 3-hydroxychromone.
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Affiliation(s)
- Probal Nag
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, India
| | - Neethu Anand
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, India
| | - Sivaranjana Reddy Vennapusa
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Maruthamala PO, Vithura, Thiruvananthapuram 695551, India
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16
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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: 13] [Impact Index Per Article: 4.3] [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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17
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Chicharro DV, Zanchet A, Bouallagui A, Rubio-Lago L, García-Vela A, Bañares L, Marggi Poullain S. Site-specific hydrogen-atom elimination in photoexcited alkyl radicals. Phys Chem Chem Phys 2021; 23:2458-2468. [PMID: 33463638 DOI: 10.1039/d0cp05410k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A prompt site-specific hydrogen-atom elimination from the α-carbon atom (Cα) has been recently reported to occur in the photodissociation of ethyl radicals following excitation at 201 nm [Chicharro et al., Chem. Sci., 2019, 10, 6494]. Such pathway was accessed by means of an initial ro-vibrational energy characterizing the radicals produced by in situ photolysis of a precursor. Here, we present experimental evidence of a similar dynamics in a series of alkyl radicals (C2H5, n-C3H7, n-C4H9, and i-C3H7) containing the same reaction coordinate, but different extended structures. The main requirements for the site-specific mechanism in the studied radicals, namely a rather high content of internal energy prior to dissociation and the participation of vibrational promoting modes, is discussed in terms of the chemical structure of the radicals. The methyl deformation mode in all alkyl radicals along with the CH bending motion in i-C3H7 appear to promote this fast H-atom elimination channel. The photodissociation dynamics of the simplest unsaturated alkyl radical, the vinyl radical (C2H3), is also discussed, showing no signal of site-specific fast H-atom elimination. The results are complemented with high-level ab initio electronic structure calculations of potential energy curves of the vinyl radical, which are compared with those previously reported for the ethyl radical.
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Affiliation(s)
- David V Chicharro
- Departamento de Química Física (Unidad Asociada I + D + i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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18
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Vinklárek IS, Suchan J, Rakovský J, Moriová K, Poterya V, Slavíček P, Fárník M. Energy partitioning and spin-orbit effects in the photodissociation of higher chloroalkanes. Phys Chem Chem Phys 2021; 23:14340-14351. [PMID: 34169306 DOI: 10.1039/d1cp01371h] [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
We investigate the photodissociation dynamics of the C-Cl bond in chloroalkanes CH3Cl, n-C3H7Cl, i-C3H7Cl, n-C5H11Cl, combining velocity map imaging (VMI) experiment and direct ab initio dynamical simulations. The Cl fragment kinetic energy distributions (KEDs) from the VMI experiment exhibit a single peak with maximum close to 0.8 eV, irrespective of the alkyl chain length and C-Cl bond position. In contrary to CH3Cl, where less than 10% of the available energy is deposited into the internal excitation of the CH3 fragment, for all higher chloroalkanes around 40% to 60% of the available energy goes into the alkyl fragment excitation. We apply the classical hard spheres and spectator model to explain the energy partitioning, and compare the classical approach with direct ab initio dynamics simulations. The alkyl chain appears to be a soft, energy absorbing unit. We further investigate the role of the spin-orbit effects on the excitation and dynamics. Combining our experimental data with theory allows us to derive the probability of the direct absorption into the triplet electronic state as well as the probabilities for intersystem crossing. The results indicate an increasing direct absorption into the triplet state with increasing alkyl chain length.
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Affiliation(s)
- Ivo S Vinklárek
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Jiří Suchan
- University of Chemistry and Technology, 166 28 Prague 6, Czech Republic.
| | - Jozef Rakovský
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Kamila Moriová
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Viktoriya Poterya
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
| | - Petr Slavíček
- University of Chemistry and Technology, 166 28 Prague 6, Czech Republic.
| | - Michal Fárník
- J. Heyrovský Institute of Physical Chemistry, v.v.i., The Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic.
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19
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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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20
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Murillo-Sánchez ML, Zanchet A, Marggi Poullain S, González-Vázquez J, Bañares L. Structural dynamics effects on the electronic predissociation of alkyl iodides. Sci Rep 2020; 10:6700. [PMID: 32317645 PMCID: PMC7174404 DOI: 10.1038/s41598-020-62982-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 03/23/2020] [Indexed: 11/26/2022] Open
Abstract
The correlation between chemical structure and predissociation dynamics has been evaluated for a series of linear and branched alkyl iodides with increasing structural complexity by means of femtosecond time-resolved velocity map imaging experiments following excitation on the second absorption band (B-band) at around 201 nm. The time-resolved images for the iodine fragment are reported and analyzed in order to extract electronic predissociation lifetimes and the temporal evolution of the anisotropy while the experimental results are supported by ab initio calculations of the potential energy curves as a function of the C-I distance. Remarkable similarities are observed for all molecules consistent with a major predissociation of the initially populated bound Rydberg states 6A″ and 7A' through a crossing with the purely repulsive states 7A″, 8A' and 8A″ leading to a major R + I*(2P1/2) (R = CH3, C2H5, n-C3H7, n-C4H9, i-C3H7 and t-C4H9) dissociation channel. The reported electronic predissociation lifetimes are found to decrease for an increasing size of the linear radical, reflecting the shifts observed in the position of the crossings in the potential energy curves, and very likely a greater non-adiabatic coupling between the initially populated Rydberg states and the repulsive states leading to dissociation induced by other coordinates associated to key vibrational normal modes. The loss of anisotropy is fully accounted for by the parent molecular rotation during predissociation and the rotational temperature of the parent molecule in the molecular beam is reasonably derived.
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Affiliation(s)
- Marta L Murillo-Sánchez
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Alexandre Zanchet
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, 37003, Salamanca, Spain
- Instituto de Física Fundamental (IFF-CSIC), Consejo Superior de Investigaciones Científicas, Serrano 123, 28006, Madrid, Spain
| | - Sonia Marggi Poullain
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
- Department of Chemistry, University of California, Berkeley, California, 94720, United States
| | - Jesús González-Vázquez
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Institute for Advanced Research in Chemical Sciences (IAdChem), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain.
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Cantoblanco, 28049, Madrid, Spain.
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21
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MacDonell RJ, Corrales ME, Boguslavskiy AE, Bañares L, Stolow A, Schuurman MS. Substituent effects on nonadiabatic excited state dynamics: Inertial, steric, and electronic effects in methylated butadienes. J Chem Phys 2020; 152:084308. [DOI: 10.1063/1.5139446] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Ryan J. MacDonell
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
| | - María E. Corrales
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | | | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Albert Stolow
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- Department of Physics, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
| | - Michael S. Schuurman
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada
- National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
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22
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Murillo-Sánchez ML, González-Vázquez J, Corrales ME, de Nalda R, Martínez-Núñez E, García-Vela A, Bañares L. Femtochemistry under scrutiny: Clocking state-resolved channels in the photodissociation of CH3I in the A-band. J Chem Phys 2020; 152:014304. [DOI: 10.1063/1.5134473] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Marta L. Murillo-Sánchez
- Departamento de Química Física, Facultad de Ciencias Químicas (Unidad Asociada de I+D+i al Consejo Superior de Investigaciones Científicas), Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Jesús González-Vázquez
- Departamento de Química and Institute for Advanced Research in Chemical Sciences (IAdChem), Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - María E. Corrales
- Departamento de Química Física, Facultad de Ciencias Químicas (Unidad Asociada de I+D+i al Consejo Superior de Investigaciones Científicas), Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Rebeca de Nalda
- Instituto de Química Física Rocasolano, CSIC, C/ Serrano 119, 28006 Madrid, Spain
| | - Emilio Martínez-Núñez
- Departamento de Química Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
| | | | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas (Unidad Asociada de I+D+i al Consejo Superior de Investigaciones Científicas), Universidad Complutense de Madrid, 28040 Madrid, Spain
- Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Cantoblanco, 28049 Madrid, Spain
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23
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Todt MA, Datta S, Rose A, Leung K, Davis HF. Subpicosecond HI elimination in the 266 nm photodissociation of branched iodoalkanes. Phys Chem Chem Phys 2020; 22:27338-27347. [DOI: 10.1039/c9cp06460e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New experiments reveal a close connection between the nonadiabatic dynamics of C–I bond fission and HI elimination in the photodissociation of branched iodoalkanes.
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Affiliation(s)
- Michael A. Todt
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - Sagnik Datta
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - Alex Rose
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - Kiana Leung
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
| | - H. Floyd Davis
- Department of Chemistry and Chemical Biology
- Baker Laboratory
- Cornell University
- Ithaca
- USA
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24
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Warne EM, Downes-Ward B, Woodhouse J, Parkes MA, Springate E, Pearcy PAJ, Zhang Y, Karras G, Wyatt AS, Chapman RT, Minns RS. Photodissociation dynamics of methyl iodide probed using femtosecond extreme ultraviolet photoelectron spectroscopy. Phys Chem Chem Phys 2020; 22:25695-25703. [DOI: 10.1039/d0cp03478a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond pump–probe photoelectron spectroscopy measurements using an extreme ultraviolet probe have been made on the photodissociation dynamics of UV (269 nm) excited CH3I.
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Affiliation(s)
- Emily M. Warne
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ
- UK
| | | | - Joanne Woodhouse
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ
- UK
| | | | - Emma Springate
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | | | - Yu Zhang
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | - Gabriel Karras
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | - Adam S. Wyatt
- Central Laser Facility
- STFC Rutherford Appleton Laboratory
- Didcot
- UK
| | | | - Russell S. Minns
- School of Chemistry
- University of Southampton
- Southampton SO17 1BJ
- UK
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25
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Abstract
Chiral molecules interact and react differently, depending on their handedness (left vs. right). This chiral recognition is the principle governing most biomolecular interactions, such as the activity of drugs or our perception of scents. In spite of this fundamental importance, a real-time (femtosecond) observation of chirality during a chemical reaction has remained out of reach in the gas phase. In the present work, we report this breakthrough with a seemingly unlikely technique: high-harmonic generation (HHG) in tailored intense near-infrared laser fields. Combining the transient-grating technique with HHG in counterrotating circularly polarized laser fields, we follow the temporal evolution of molecular chirality during a chemical reaction from the unexcited electronic ground state through the transition-state region to the final achiral products. Chiral molecules interact and react differently with other chiral objects, depending on their handedness. Therefore, it is essential to understand and ultimately control the evolution of molecular chirality during chemical reactions. Although highly sophisticated techniques for the controlled synthesis of chiral molecules have been developed, the observation of chirality on the natural femtosecond time scale of a chemical reaction has so far remained out of reach in the gas phase. Here, we demonstrate a general experimental technique, based on high-harmonic generation in tailored laser fields, and apply it to probe the time evolution of molecular chirality during the photodissociation of 2-iodobutane. These measurements show a change in sign and a pronounced increase in the magnitude of the chiral response over the first 100 fs, followed by its decay within less than 500 fs, revealing the photodissociation to achiral products. The observed time evolution is explained in terms of the variation of the electric and magnetic transition-dipole moments between the lowest electronic states of the cation as a function of the reaction coordinate. These results open the path to investigations of the chirality of molecular-reaction pathways, light-induced chirality in chemical processes, and the control of molecular chirality through tailored laser pulses.
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26
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Wang H, Odelius M, Prendergast D. A combined multi-reference pump-probe simulation method with application to XUV signatures of ultrafast methyl iodide photodissociation. J Chem Phys 2019; 151:124106. [PMID: 31575206 DOI: 10.1063/1.5116816] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
UV pump-XUV/X-ray probe measurements have been successfully applied in the study of photo-induced chemical reactions. Although rich element-specific electronic structure information is accessible within XUV/X-ray (inner-shell) absorption spectra, it can be difficult to interpret the chemistry directly from the spectrum without supporting theoretical simulations. A multireference method to completely simulate UV pump-XUV/X-ray probe measurement has been developed and applied to study the methyl iodide photodissociation process. Multireference, fewest-switches surface hopping (FSSH) trajectories were used to explore the coupled electronic and ionic dynamics upon photoexcitation of methyl iodide. Interpretation of previous measurements is provided by associated multireference, restricted active space, inner-shell spectral simulations. This combination of multireference FSSH trajectories and XUV spectra provides an interpretation of transient features appearing in previous measurements within the first 100 fs after photoexcitation and validates the significant branching ratio in the final excited-state population. This methodology should prove useful for interpretation of the increasing number of inner-shell probe studies of molecular excited states or for directing new experiments toward interesting regions of the potential energy landscape.
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Affiliation(s)
- Han Wang
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Michael Odelius
- Department of Physics, Stockholm University, AlbaNova University Center, SE-106 91 Stockholm, Sweden
| | - David Prendergast
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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27
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Marggi Poullain S, Recio P, Chicharro DV, Rubio-Lago L, González-Vázquez J, Bañares L. Dynamics of the photodissociation of ethyl iodide from the origin of the B band. A slice imaging study. Phys Chem Chem Phys 2019; 21:14250-14260. [PMID: 30565605 DOI: 10.1039/c8cp06482b] [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
The photodissociation dynamics and stereodynamics of ethyl iodide from the origin of the second absorption B-band have been investigated combining pulsed slicFe imaging with resonance enhanced multiphoton ionization (REMPI) detection of all fragments, I(2P3/2), I*(2P1/2) and C2H5. The I*(2P1/2) atom action spectrum recorded as a function of the excitation wavelength permits one to identify and select the 0 origin of this band at 201.19 nm (49 704 cm-1). Translational energy distributions and angular distributions for all fragments and semiclassical Dixon's bipolar moments for the C2H5 fragment are presented and discussed along with high-level ab initio calculations of potential energy curves as a function of the C-I distance. A predissociative mechanism governs the dynamics where in a first step a bound Rydberg state corresponding to the 5pπI→ 6sI transition is populated by the 201.19 nm-photon absorption. A curve crossing with a repulsive state located within the Franck-Condon geometry leads to direct dissociation into the major channel C2H5 + I*(2P1/2). A small amount of I(2P3/2) atoms is nevertheless observed and presumably attributed to a second curve crossing with a repulsive state from the A-band.
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Affiliation(s)
- Sonia Marggi Poullain
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Pedro Recio
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - David V Chicharro
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Luis Rubio-Lago
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Jesús González-Vázquez
- Departamento de Química, Módulo 13, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain and Institute for Advanced Research in Chemical Sciences (IAdChem), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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28
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Malakar Y, Pearson WL, Zohrabi M, Kaderiya B, P. KR, Ziaee F, Xue S, Le AT, Ben-Itzhak I, Rolles D, Rudenko A. Time-resolved imaging of bound and dissociating nuclear wave packets in strong-field ionized iodomethane. Phys Chem Chem Phys 2019; 21:14090-14102. [DOI: 10.1039/c8cp07032f] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the results of a time-resolved coincident ion momentum imaging experiment probing nuclear wave packet dynamics in the strong-field ionization and dissociation of iodomethane (CH3I).
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29
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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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30
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Mai S, Marquetand P, González L. Nonadiabatic dynamics: The SHARC approach. WILEY INTERDISCIPLINARY REVIEWS. COMPUTATIONAL MOLECULAR SCIENCE 2018; 8:e1370. [PMID: 30450129 PMCID: PMC6220962 DOI: 10.1002/wcms.1370] [Citation(s) in RCA: 224] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/05/2018] [Accepted: 04/06/2018] [Indexed: 12/12/2022]
Abstract
We review the Surface Hopping including ARbitrary Couplings (SHARC) approach for excited-state nonadiabatic dynamics simulations. As a generalization of the popular surface hopping method, SHARC allows simulating the full-dimensional dynamics of molecules including any type of coupling terms beyond nonadiabatic couplings. Examples of these arbitrary couplings include spin-orbit couplings or dipole moment-laser field couplings, such that SHARC can describe ultrafast internal conversion, intersystem crossing, and radiative processes. The key step of the SHARC approach consists of a diagonalization of the Hamiltonian including these couplings, such that the nuclear dynamics is carried out on potential energy surfaces including the effects of the couplings-this is critical in any applications considering, for example, transition metal complexes or strong laser fields. We also give an overview over the new SHARC2.0 dynamics software package, released under the GNU General Public License, which implements the SHARC approach and several analysis tools. The review closes with a brief survey of applications where SHARC was employed to study the nonadiabatic dynamics of a wide range of molecular systems. This article is categorized under: Theoretical and Physical Chemistry > Reaction Dynamics and KineticsSoftware > Simulation MethodsSoftware > Quantum Chemistry.
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Affiliation(s)
- Sebastian Mai
- Institute of Theoretical Chemistry, Faculty of Chemistry University of Vienna Vienna Austria
| | - Philipp Marquetand
- Institute of Theoretical Chemistry, Faculty of Chemistry University of Vienna Vienna Austria
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry University of Vienna Vienna Austria
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31
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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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Multidimensional Analysis of Time-Resolved Charged Particle Imaging Experiments. APPLIED SCIENCES-BASEL 2018. [DOI: 10.3390/app8081227] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We present a tutorial to realize a multidimensional fitting procedure capable of extracting all the relevant information contained in a sequence of charged particle images acquired as a function of time in femtosecond pump–probe experiments. The images are reproduced using a 3D fitting method, which provides the velocity (or center-of-mass kinetic energy) and angular distributions contained in the images and their time evolution. A detailed example of the method is shown through the analysis of the time-resolved predissociation dynamics of CH3I on the B-band origin (Gitzinger et al., J. Chem. Phys.2010, 133, 234313). We show that the multidimensional approach is essential for the analysis of complex images that contain several overlapping contributions where reduced dimensionality analyses cannot provide a reliable description of the features present in the image sequence. This methodology can be generalized to many types of multidimensional data analysis.
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Baumann A, Rompotis D, Schepp O, Wieland M, Drescher M. Time-Resolved Dissociation Dynamics of Iodomethane Resulting from Rydberg and Valence Excitation. J Phys Chem A 2018; 122:4779-4784. [DOI: 10.1021/acs.jpca.8b01248] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arne Baumann
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
| | | | - Oliver Schepp
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
| | - Marek Wieland
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
- Center for Free-Electron Laser Science—CFEL, Hamburg 22607, Germany
| | - Markus Drescher
- Institute for Experimental Physics, University Hamburg, Hamburg 22761, Germany
- The Hamburg Centre for Ultrafast Imaging—CUI, Hamburg 22761, Germany
- Center for Free-Electron Laser Science—CFEL, Hamburg 22607, Germany
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Murillo-Sánchez ML, Marggi Poullain S, Bajo JJ, Corrales ME, González-Vázquez J, Solá IR, Bañares L. Halogen-atom effect on the ultrafast photodissociation dynamics of the dihalomethanes CH2ICl and CH2BrI. Phys Chem Chem Phys 2018; 20:20766-20778. [PMID: 30020280 DOI: 10.1039/c8cp03600d] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Real time photodissociation of dihalomethanes has been measured by femtosecond velocity map imaging to disentangle the effect of the halogen-atom on the carbon–iodine cleavage dynamics.
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Affiliation(s)
- Marta L. Murillo-Sánchez
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Sonia Marggi Poullain
- Departamento de Química
- Módulo 13
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
| | - Juan J. Bajo
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - María E. Corrales
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Jesús González-Vázquez
- Departamento de Química
- Módulo 13
- Facultad de Ciencias
- Universidad Autónoma de Madrid
- 28049 Madrid
| | - Ignacio R. Solá
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
| | - Luis Bañares
- Departamento de Química Física
- Facultad de Ciencias Químicas
- Universidad Complutense de Madrid
- 28040 Madrid
- Spain
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36
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Murillo-Sánchez M, Marggi Poullain S, González-Vázquez J, Corrales M, Balerdi G, Bañares L. Femtosecond photodissociation dynamics of chloroiodomethane in the first absorption band. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.02.037] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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37
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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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38
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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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39
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Attar AR, Bhattacherjee A, Leone SR. Direct Observation of the Transition-State Region in the Photodissociation of CH3I by Femtosecond Extreme Ultraviolet Transient Absorption Spectroscopy. J Phys Chem Lett 2015; 6:5072-7. [PMID: 26636176 DOI: 10.1021/acs.jpclett.5b02489] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Femtosecond extreme ultraviolet (XUV) pulses produced by high harmonic generation are used to probe the transition-state region in the 266 nm photodissociation of CH3I by the real-time evolution of core-to-valence transitions near the iodine N-edge at 45-60 eV. During C-I bond breaking, new core-to-valence electronic states appear in the spectra, which decay concomitantly with the rise of the atomic iodine resonances of I((2)P3/2) and I*((2)P1/2). The short-lived features are assigned to repulsive valence-excited transition-state regions of (3)Q0 and (1)Q1, which can connect to transient core-excited states via promotion of 4d(I) core electrons. A simplified one-electron transition picture is described that accurately predicts the relative energies of the transient states observed. The transition-state resonances reach a maximum at ∼40 fs and decay to complete C-I dissociation in ∼90 fs, representing the shortest-lived chemical transition state observed by core-level, XUV, or X-ray spectroscopy.
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Affiliation(s)
- 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
| | - 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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Richter M, Mai S, Marquetand P, González L. Ultrafast intersystem crossing dynamics in uracil unravelled by ab initio molecular dynamics. Phys Chem Chem Phys 2014; 16:24423-36. [PMID: 25301389 PMCID: PMC4391640 DOI: 10.1039/c4cp04158e] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 10/03/2014] [Indexed: 11/21/2022]
Abstract
Ab initio molecular dynamics simulations have been performed in order to investigate the relaxation dynamics of uracil after UV excitation in gas phase. Intersystem crossing (ISC) has been included for the first time into time-dependent simulations of uracil, allowing the system to relax in the singlet as well as in the triplet states. The results show a qualitatively different picture than similar simulations that include singlet states only. The inclusion of ISC effectively quenches the relaxation to the singlet ground state and instead privileges transitions from the low-lying nπ* state (S1) to a ππ* triplet state (T2) followed by rapid internal conversion to the lowest triplet state.
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Affiliation(s)
- Martin Richter
- Institute of Theoretical Chemistry , Währinger Str. 17 , 1090 Vienna , Austria .
| | - Sebastian Mai
- Institute of Theoretical Chemistry , Währinger Str. 17 , 1090 Vienna , Austria .
| | - Philipp Marquetand
- Institute of Theoretical Chemistry , Währinger Str. 17 , 1090 Vienna , Austria .
| | - Leticia González
- Institute of Theoretical Chemistry , Währinger Str. 17 , 1090 Vienna , Austria .
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41
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Kinzel D, Zilberg S, González L. Gas-phase electrophilic aromatic substitution mechanism with strong electrophiles explained by ab initio non-adiabatic dynamics. Phys Chem Chem Phys 2014; 16:18686-9. [PMID: 25080210 DOI: 10.1039/c4cp01456a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ab initio non-adiabatic dynamics is used to monitor the attack of CH3(+) to benzene. The results show that in the gas phase the reaction is ultrafast and is governed by a single electron transfer producing a radical pair.
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Affiliation(s)
- Daniel Kinzel
- Institute of Theoretical Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria.
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