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Walmsley T, McManus JW, Kumagai Y, Nagaya K, Harries J, Iwayama H, Ashfold MNR, Britton M, Bucksbaum PH, Downes-Ward B, Driver T, Heathcote D, Hockett P, Howard AJ, Lee JWL, Liu Y, Kukk E, Milesevic D, Minns RS, Niozu A, Niskanen J, Orr-Ewing AJ, Owada S, Robertson PA, Rolles D, Rudenko A, Ueda K, Unwin J, Vallance C, Brouard M, Burt M, Allum F, Forbes R. The Role of Momentum Partitioning in Covariance Ion Imaging Analysis. J Phys Chem A 2024. [PMID: 38713032 DOI: 10.1021/acs.jpca.4c00999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
We present results from a covariance ion imaging study, which employs extensive filtering, on the relationship between fragment momenta to gain deeper insight into photofragmentation dynamics. A new data analysis approach is introduced that considers the momentum partitioning between the fragments of the breakup of a molecular polycation to disentangle concurrent fragmentation channels, which yield the same ion species. We exploit this approach to examine the momentum exchange relationship between the products, which provides direct insight into the dynamics of molecular fragmentation. We apply these techniques to extensively characterize the dissociation of 1-iodopropane and 2-iodopropane dications prepared by site-selective ionization of the iodine atom using extreme ultraviolet intense femtosecond laser pulses with a photon energy of 95 eV. Our assignments are supported by classical simulations, using parameters largely obtained directly from the experimental data.
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Affiliation(s)
- Tiffany Walmsley
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Joseph W McManus
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Yoshiaki Kumagai
- Department of Applied Physics, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
| | - Kiyonobu Nagaya
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - James Harries
- National Institutes for Quantum Science and Technology (QST), SPring-8, Kouto 1-1-1, Sayo, Hyogo 679-5148, Japan
| | - Hiroshi Iwayama
- Institute for Molecular Science, Okazaki 444-8585, Japan
- Sokendai (The Graduate University for Advanced Studies), Okazaki 444-8585, Japan
| | | | - Mathew Britton
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Philip H Bucksbaum
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Briony Downes-Ward
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Taran Driver
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - David Heathcote
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Paul Hockett
- National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Andrew J Howard
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Jason W L Lee
- Deutsches Elektronen-Synchrotron (DESY), Hamburg 22607, Germany
| | - Yusong Liu
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Edwin Kukk
- Department of Physics and Astronomy, University of Turku, Turku FI-20014, Finland
| | - Dennis Milesevic
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Russell S Minns
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Akinobu Niozu
- Graduate School of Advanced Science and Engineering, Hiroshima University, Hiroshima 739-8526, Japan
| | - Johannes Niskanen
- Department of Physics and Astronomy, University of Turku, Turku FI-20014, Finland
| | | | - Shigeki Owada
- RIKEN SPring-8 Center, Sayo, Hyogo 679-5148, Japan
- Japan Synchrotron Radiation Research Institute, Sayo, Hyogo 679-5198, Japan
| | - Patrick A Robertson
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Daniel Rolles
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Artem Rudenko
- J.R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Kiyoshi Ueda
- Department of Chemistry, Tohoku University, Sendai 980-8578, Japan
| | - James Unwin
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Claire Vallance
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Mark Brouard
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Michael Burt
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
| | - Felix Allum
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
- PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
| | - Ruaridh Forbes
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, United States
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McManus JW, Allum F, Featherstone J, Lam CS, Brouard M. Two-Dimensional Projected-Momentum Covariance Mapping for Coulomb Explosion Imaging. J Phys Chem A 2024; 128:3220-3229. [PMID: 38607425 PMCID: PMC11056990 DOI: 10.1021/acs.jpca.4c01084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/13/2024]
Abstract
We introduce projected-momentum covariance mapping, an extension of recoil-frame covariance mapping for 2D ion imaging studies. By considering the two-dimensional projection of the ion momenta as recorded by the detector, one opens the door to a complex suite of analysis tools adapted from three-dimensional momentum imaging studies. This includes the use of different frames of reference to unravel the dynamics of fragmentation and the application of fragment momentum constraints to isolate specific fragmentation channels. The technique is demonstrated on data from a two-dimensional ion imaging study of the Coulomb explosion of the cis and trans isomers of 1,2-dichloroethene, following strong-field ionization by an intense near-infrared femtosecond laser pulse. Classical simulations are used to guide the interpretation of projected-momentum covariance maps. The results offer a detailed insight into the distinct Coulomb explosion dynamics for this pair of isomers and lay the groundwork for future time-resolved studies of photoisomerization dynamics in this molecular system.
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Affiliation(s)
- Joseph W. McManus
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
| | | | - Josh Featherstone
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
| | - Chow-Shing Lam
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
| | - Mark Brouard
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Wang XD, Robertson PA, Cascarini FJJ, Quinn MS, McManus JW, Orr-Ewing AJ. Observation of Rainbows in the Rotationally Inelastic Scattering of NO with CH 4. J Phys Chem A 2019; 123:7758-7767. [PMID: 31442046 DOI: 10.1021/acs.jpca.9b06806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Using a combination of velocity-map imaging and resonance-enhanced multiphoton ionization detection with crossed molecular beam scattering, the dynamics of rotational energy transfer have been examined for NO in collisions with CH4 at a mean collision energy of 700 cm-1. The images of NO scattered into individual rotational (jNO') and spin-orbit (Ω) levels typically exhibit a single broad maximum that gradually shifts from the forward to the backward scattering direction with increasing rotational excitation (i.e., larger ΔjNO). The rotational rainbow angles calculated with a two-dimensional hard ellipse model show reasonable agreement with the observed angles corresponding to the maxima in the differential cross sections extracted from the images for higher ΔjNO transitions, but there are clear discrepancies for lower ΔjNO (in particular, final rotational levels with jNO' = 7.5 and 8.5). The sharply forward scattered angular distributions for these lower ΔjNO transitions better agree with the predictions of an L-type rainbow model. The more highly rotationally excited NO appears to coincide with low rotational excitation of the co-product CH4, indicating a degree of rotational product-pair anticorrelation in this bimolecular scattering.
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Affiliation(s)
- Xu-Dong Wang
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , United Kingdom
| | - Patrick A Robertson
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , United Kingdom
| | - Frederick J J Cascarini
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , United Kingdom
| | - Mitchell S Quinn
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , United Kingdom
| | - Joseph W McManus
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , United Kingdom
| | - Andrew J Orr-Ewing
- School of Chemistry , University of Bristol , Cantock's Close , Bristol , BS8 1TS , United Kingdom
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