1
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Vacuum ultraviolet photodissociation dynamics of OCS via the F Rydberg state: The S( 3P J=2,1,0) product channels. CHINESE J CHEM PHYS 2022. [DOI: 10.1063/1674-0068/cjcp2112271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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2
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Ma Y, Liu J, Li F, Wang F, Kitsopoulos TN. Roaming Dynamics in the Photodissociation of Formic Acid at 230 nm. J Phys Chem A 2019; 123:3672-3677. [PMID: 30969120 DOI: 10.1021/acs.jpca.9b00724] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Roaming dynamics is observed in the photodissociation of formic acid (HCOOH) at 230 nm by using the slice imaging method. In combination with rotational state selective (2 + 1) resonance-enhanced multiphoton ionization of the CO fragments, the speed distributions of the CO fragments exhibit a low recoil velocity at low rotational levels of J = 9 and 20, while the velocity distributions of CO at high rotational levels of J = 30 and 48 show a relatively large recoil velocity. The experimental results indicate that the roaming of OH radical should be related with the formation of CO + H2O channel at the present photolysis energy. Unlike the roaming pathways occurring in H2CO that can be described by loose flat potential, our CO speed distribution analysis suggests the presence of a "tight" flat potential in the roaming dynamics of HCOOH molecules.
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Affiliation(s)
- Yujie Ma
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Jiaxing Liu
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Fangfang Li
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Fengyan Wang
- Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials , Fudan University , Shanghai 200433 , P. R. China
| | - Theofanis N Kitsopoulos
- Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Institute of Electronic Structure and Laser, FORTH, Heraklion, Greece; Department of Chemistry , University of Crete , Heraklion , Greece
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3
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Ashfold MNR, Ingle RA, Karsili TNV, Zhang J. Photoinduced C–H bond fission in prototypical organic molecules and radicals. Phys Chem Chem Phys 2019; 21:13880-13901. [DOI: 10.1039/c8cp07454b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We survey and assess current knowledge regarding the primary photochemistry of hydrocarbon molecules and radicals.
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Affiliation(s)
| | | | | | - Jingsong Zhang
- Department of Chemistry
- University of California at Riverside
- Riverside
- USA
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4
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Suits AG. Invited Review Article: Photofragment imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:111101. [PMID: 30501356 DOI: 10.1063/1.5045325] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Accepted: 10/25/2018] [Indexed: 06/09/2023]
Abstract
Photodissociation studies in molecular beams that employ position-sensitive particle detection to map product recoil velocities emerged thirty years ago and continue to evolve with new laser and detector technologies. These powerful methods allow application of tunable laser detection of single product quantum states, simultaneous measurement of velocity and angular momentum polarization, measurement of joint product state distributions for the detected and undetected products, coincident detection of multiple product channels, and application to radicals and ions as well as closed-shell molecules. These studies have permitted deep investigation of photochemical dynamics for a broad range of systems, revealed new reaction mechanisms, and addressed problems of practical importance in atmospheric, combustion, and interstellar chemistry. This review presents an historical overview, a detailed technical account of the range of methods employed, and selected experimental highlights illustrating the capabilities of the method.
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Affiliation(s)
- Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, USA
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5
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Lipciuc ML, Gardiner SH, Karsili TNV, Lee JWL, Heathcote D, Ashfold MNR, Vallance C. Photofragmentation dynamics of N,N-dimethylformamide following excitation at 193 nm. J Chem Phys 2018; 147:013941. [PMID: 28688414 DOI: 10.1063/1.4983704] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
N,N-dimethylformamide, HCON(CH3)2, is a useful model compound for investigating the peptide bond photofragmentation dynamics. We report data from a comprehensive experimental and theoretical study into the photofragmentation dynamics of N,N-dimethylformamide in the gas phase at 193 nm. Through a combination of velocity-map imaging and hydrogen atom Rydberg tagging photofragment translational spectroscopy we have identified two primary fragmentation channels, namely, fission of the N-CO "peptide" bond and N-CH3 bond fission leading to the loss of CH3. The possible fragmentation channels leading to the observed products are rationalised with recourse to CASPT2 calculations of the ground and first few excited-state potential energy curves along the relevant dissociation coordinates, and the results are compared with the data from previous experimental and theoretical studies on the same system.
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Affiliation(s)
- M Laura Lipciuc
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Sara H Gardiner
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Tolga N V Karsili
- School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, United Kingdom
| | - Jason W L Lee
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - David Heathcote
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Michael N R Ashfold
- School of Chemistry, University of Bristol, Cantocks Close, Bristol BS8 1TS, United Kingdom
| | - Claire Vallance
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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6
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Larsson HR, Riedel J, Wei J, Temps F, Hartke B. Resonance dynamics of DCO (X̃ A′2) simulated with the dynamically pruned discrete variable representation (DP-DVR). J Chem Phys 2018; 148:204309. [DOI: 10.1063/1.5026459] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Henrik R. Larsson
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Jens Riedel
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Jie Wei
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Friedrich Temps
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
| | - Bernd Hartke
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstraße 40, 24098 Kiel, Germany
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7
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Quinn MS, Andrews DU, Nauta K, Jordan MJT, Kable SH. The energy dependence of CO(v,J) produced from H2CO via the transition state, roaming, and triple fragmentation channels. J Chem Phys 2017; 147:013935. [DOI: 10.1063/1.4983138] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Mitchell S. Quinn
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | - Duncan U. Andrews
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Klaas Nauta
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
| | | | - Scott H. Kable
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia
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8
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Epshtein M, Monsa Y, Portnov A, Bar I. Velocity map ion imaging and velocity-resolved action spectroscopy of H atom photofragments via Doppler-free multiphoton ionization. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.03.075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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9
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Savee JD, Borkar S, Welz O, Sztáray B, Taatjes CA, Osborn DL. Multiplexed Photoionization Mass Spectrometry Investigation of the O(3P) + Propyne Reaction. J Phys Chem A 2015; 119:7388-403. [DOI: 10.1021/acs.jpca.5b00491] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- John D. Savee
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - Sampada Borkar
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Oliver Welz
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - Bálint Sztáray
- Department
of Chemistry, University of the Pacific, Stockton, California 95211, United States
| | - Craig A. Taatjes
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
| | - David L. Osborn
- Combustion
Research Facility, Sandia National Laboratories, Mail Stop 9055, Livermore, California 94551-0969, United States
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10
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Lu Z, Chang YC, Yin QZ, Ng CY, Jackson WM. Photochemistry. Evidence for direct molecular oxygen production in CO₂ photodissociation. Science 2014; 346:61-4. [PMID: 25278605 DOI: 10.1126/science.1257156] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Photodissociation of carbon dioxide (CO2) has long been assumed to proceed exclusively to carbon monoxide (CO) and oxygen atom (O) primary products. However, recent theoretical calculations suggested that an exit channel to produce C + O2 should also be energetically accessible. Here we report the direct experimental evidence for the C + O2 channel in CO2 photodissociation near the energetic threshold of the C((3)P) + O2(X(3)Σ(g)(-)) channel with a yield of 5 ± 2% using vacuum ultraviolet laser pump-probe spectroscopy and velocity-map imaging detection of the C((3)PJ) product between 101.5 and 107.2 nanometers. Our results may have implications for nonbiological oxygen production in CO2-heavy atmospheres.
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Affiliation(s)
- Zhou Lu
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Yih Chung Chang
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Qing-Zhu Yin
- Department of Earth and Planetary Sciences, University of California, Davis, CA 95616, USA
| | - C Y Ng
- Department of Chemistry, University of California, Davis, CA 95616, USA.
| | - William M Jackson
- Department of Chemistry, University of California, Davis, CA 95616, USA.
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11
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Epshtein M, Portnov A, Kupfer R, Rosenwaks S, Bar I. Enhanced sensitivity in H photofragment detection by two-color reduced-Doppler ion imaging. J Chem Phys 2013; 139:184201. [PMID: 24320267 DOI: 10.1063/1.4828891] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Two-color reduced-Doppler (TCRD) and one-color velocity map imaging (VMI) were used for probing H atom photofragments resulting from the ~243.1 nm photodissociation of pyrrole. The velocity components of the H photofragments were probed by employing two counterpropagating beams at close and fixed wavelengths of 243.15 and 243.12 nm in TCRD and a single beam at ~243.1 nm, scanned across the Doppler profile in VMI. The TCRD imaging enabled probing of the entire velocity distribution in a single pulse, resulting in enhanced ionization efficiency, as well as improved sensitivity and signal-to-noise ratio. These advantages were utilized for studying the pyrrole photodissociation at ~243.1 and 225 nm, where the latter wavelength provided only a slight increase in the H yield over the self-signal from the probe beams. The TCRD imaging enabled obtaining high quality H(+) images, even for the low H photofragment yields formed in the 225 nm photolysis process, and allowed determining the velocity distributions and anisotropy parameters and getting insight into pyrrole photodissociation.
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Affiliation(s)
- Michael Epshtein
- Department of Physics, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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12
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Hobday N, Quinn MS, Nauta K, Andrews DU, Jordan MJT, Kable SH. Experimental and Theoretical Investigation of Triple Fragmentation in the Photodissociation Dynamics of H2CO. J Phys Chem A 2013; 117:12091-103. [DOI: 10.1021/jp404895y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicholas Hobday
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | - Mitch S. Quinn
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | - Klaas Nauta
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | - Duncan U. Andrews
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
| | | | - Scott H. Kable
- School of Chemistry, University of Sydney, Sydney NSW 2006, Australia
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13
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Welz O, Zádor J, Savee JD, Sheps L, Osborn DL, Taatjes CA. Low-Temperature Combustion Chemistry of n-Butanol: Principal Oxidation Pathways of Hydroxybutyl Radicals. J Phys Chem A 2013; 117:11983-2001. [DOI: 10.1021/jp403792t] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oliver Welz
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Judit Zádor
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - John D. Savee
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Leonid Sheps
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - David L. Osborn
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Craig A. Taatjes
- Combustion
Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551-0969, United States
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14
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Steinbauer M, Giegerich J, Fischer KH, Fischer I. The photodissociation dynamics of the ethyl radical, C2H5, investigated by velocity map imaging. J Chem Phys 2012; 137:014303. [DOI: 10.1063/1.4731285] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Savee JD, Welz O, Taatjes CA, Osborn DL. New mechanistic insights to the O(3P) + propene reaction from multiplexed photoionization mass spectrometry. Phys Chem Chem Phys 2012; 14:10410-23. [DOI: 10.1039/c2cp41200d] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Chao MH, Tsai PY, Lin KC. Molecular elimination of methyl formate in photolysis at 234 nm: roaming vs. transition state-type mechanism. Phys Chem Chem Phys 2011; 13:7154-61. [DOI: 10.1039/c0cp02710c] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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17
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Silva R, Gichuhi WK, Kislov VV, Landera A, Mebel AM, Suits AG. UV photodissociation of cyanoacetylene: a combined ion imaging and theoretical investigation. J Phys Chem A 2009; 113:11182-6. [PMID: 19827850 DOI: 10.1021/jp904183a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photodissociation of cyanoacetylene, one of the key minor constituents in Titan's atmosphere, was studied in a molecular beam under collisionless conditions using direct current slice ion imaging at 121.6, 193.3, and 243.2 nm. The experimental results were augmented by high-level theoretical calculations of stationary points on the ground-state and second excited singlet potential surfaces, and by statistical calculations of the dissociation rates and product branching on the ground-state surface. Results at 121.6 and 243.2 nm are nearly identical, suggesting that the 243.2 nm photodissociation is the result of a two-photon process. The translational energy distributions show only a modest fraction of the available energy in translation and are consistent with barrierless dissociation from the ground state. The results at 193.3 nm are quite distinct, showing up to half of the available energy in translation, implying dissociation with an exit barrier. The 193 nm result is ascribed to dissociation on the S(1) potential energy surface. The theoretical calculations show significant rates for H loss on the ground state at 193 nm and significant branching to CN + CCH at 157 nm and higher.
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Affiliation(s)
- R Silva
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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18
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Chichinin AI, Gericke KH, Kauczok S, Maul C. Imaging chemical reactions – 3D velocity mapping. INT REV PHYS CHEM 2009. [DOI: 10.1080/01442350903235045] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Goncharov V, Herath N, Arregui A, Bañares L, Suits AG. Masked Velocity Map Imaging: A One-Laser-Beam Doppler-Free Spectroscopic Technique. J Phys Chem A 2009; 113:3840-3. [DOI: 10.1021/jp809711n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Vasiliy Goncharov
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Nuradhika Herath
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Andrés Arregui
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Luis Bañares
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Arthur G. Suits
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, and Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
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20
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Huang C, Estillore AD, Suits AG. State-selected imaging of HCCO radical photodissociation dynamics. J Chem Phys 2008; 128:134301. [DOI: 10.1063/1.2831788] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Goldberg NT, Koszinowski K, Pomerantz AE, Zare RN. Doppler-free ion imaging of hydrogen molecules produced in bimolecular reactions. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2006.11.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Rubio-Lago L, Amaral GA, Arregui A, Izquierdo JG, Wang F, Zaouris D, Kitsopoulos TN, Bañares L. Slice imaging of the photodissociation of acetaldehyde at 248 nm. Evidence of a roaming mechanism. Phys Chem Chem Phys 2007; 9:6123-7. [DOI: 10.1039/b708310f] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Koszinowski K, Goldberg NT, Pomerantz AE, Zare RN. Construction and calibration of an instrument for three-dimensional ion imaging. J Chem Phys 2006; 125:133503. [PMID: 17029486 DOI: 10.1063/1.2217742] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We describe a new instrument based on a delay-line detector for imaging the complete three-dimensional velocity distribution of photoionized products from photoinitiated reactions. Doppler-free [2+1] resonantly enhanced multiphoton ionization (REMPI) of H and D atoms formed upon photolysis of HBr and DBr in the range 203 nm < or = lambda photolysis < or = 243 nm yields radial speeds measured to be accurate within 1% of those calculated. The relative speed resolution is about 5% and limited by photoionization recoil broadening. A relative speed resolution of 3.4% is obtained for [3+1] REMPI, which minimizes the ionization recoil. We also determine the branching ratio between ground-state and spin-orbit-excited product channels and their associated anisotropies. We find that DBr photolysis dynamics differs slightly from its HBr counterpart.
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Affiliation(s)
- Konrad Koszinowski
- Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA
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24
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Abstract
We demonstrate a two-color reduced-Doppler probe for ion imaging that, in many applications, offers advantages over conventional 2+1 resonance-enhanced multiphoton ionization detection. Using counterpropagating beams of two different colors, one of which is broadband 266 nm, we achieve convenient and sensitive D atom detection without the need for Doppler scanning. We demonstrate the approach using 224 nm photodissociation of DBr. This method improves the sensitivity and signal-to-noise ratio and presents advantages and opportunities for use in the other systems.
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Affiliation(s)
- Cunshun Huang
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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25
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Huang C, Lahankar SA, Hwa Kim M, Zhang B, Suits AG. Doppler-free/Doppler-sliced ion imaging. Phys Chem Chem Phys 2006; 8:4652-4. [PMID: 17047761 DOI: 10.1039/b612324d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We demonstrate a hybrid Doppler-free/Doppler-sliced ion imaging approach that is well-suited for detection of H or D atoms. The method relies on 2 + 1 resonant ionization with identical, nearly counterpropagating beams that are coplanar but directed at a small angle relative to the detector face. This results in Doppler selection of the velocity component along the time of flight axis but Doppler-free detection in the plane perpendicular to this axis. The results show high signal level and excellent slicing ( approximately 5%), yielding velocity resolution completely determined by cation recoil in the ionization step.
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Affiliation(s)
- Cunshun Huang
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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