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Paul D, Yang Z, Goettl SJ, Thomas AM, He C, Suits AG, Parker DH, Kaiser RI. Photodissociation Dynamics of Astrophysically Relevant Propyl Derivatives (C 3H 7X; X = CN, OH, HCO) at 157 nm Exploiting an Ultracompact Velocity Map Imaging Spectrometer: The (Iso)Propyl Channel. J Phys Chem A 2022; 126:5768-5775. [PMID: 35993843 DOI: 10.1021/acs.jpca.2c04430] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The photodissociation dynamics of astrophysically relevant propyl derivatives (C3H7X; X = CN, OH, HCO) at 157 nm exploiting an ultracompact velocity map imaging (UVMIS) setup has been reported. The successful operation of UVMIS allowed the exploration of the 157 nm photodissociation of six (iso)propyl systems─n/i-propyl cyanide (C3H7CN), n/i-propyl alcohol (C3H7OH), and (iso)butanal (C3H7CHO)─to explore the C3H7 loss channel. The distinct center-of-mass translational energy distributions for the i-C3H7X (X= CN, OH, HCO) could be explained through preferential excitation of the low frequency C-H bending modes of the formyl moiety compared to the higher frequency stretching of the cyano and hydroxy moieties. Although the ionization energy of the n-C3H7 radical exceeds the energy of a 157 nm photon, C3H7+ was observed in the n-C3H7X (X = CN, OH, HCO) systems as a result of photoionization of vibrationally "hot" n-C3H7 fragments, photoionization of i-C3H7 after a hydrogen shift in vibrationally "hot" n-C3H7 radicals, and/or two-photon ionization. Our experiments reveal that at least the isopropyl radical (i-C3H7) and possibly the normal propyl radical (n-C3H7) should be present in the interstellar medium and hence searched for by radio telescopes.
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Affiliation(s)
- Dababrata Paul
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Zhenghai Yang
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Shane J Goettl
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Aaron M Thomas
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Chao He
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
| | - Arthur G Suits
- Department of Chemistry, University of Missouri, Columbia, Missouri 65211, United States
| | - David H Parker
- Department of Laser Physics, Institute for Molecules and Materials, Radboud University, Nijmegen 6500, The Netherlands
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, Hawaii 96822, United States
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Shi Y, Kamasah A, Joalland B, Suits AG. Crossed-beam DC slice imaging of fluorine atom reactions with linear alkanes. J Chem Phys 2015; 142:184309. [PMID: 25978893 DOI: 10.1063/1.4919099] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report the reaction dynamics of F atom with selected alkanes studied by crossed beam scattering with DC slice ion imaging. The target alkanes are propane, n-butane, and n-pentane. The product alkyl radicals are probed by 157 nm single photon ionization following reaction at a collision energy of ∼10 kcal mol(-1). The analyzed data are compared with the corresponding theoretical studies. Reduced translational energy distributions for each system show similar trends with little of the reaction exoergicity appearing in translation. However, the pentane reaction shows a somewhat smaller fraction of available energy in translation than the other two, suggesting greater energy channeled into pentyl internal degrees of freedom. The center-of-mass angular distributions all show backscattering as well as sharp forward scattering that decreases in relative intensity with the size of the molecule. Possible reasons for these trends are discussed.
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Affiliation(s)
- Yuanyuan Shi
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Alexander Kamasah
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Baptiste Joalland
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
| | - Arthur G Suits
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, USA
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Joalland B, Shi Y, Estillore AD, Kamasah A, Mebel AM, Suits AG. Dynamics of chlorine atom reactions with hydrocarbons: insights from imaging the radical product in crossed beams. J Phys Chem A 2014; 118:9281-95. [PMID: 25076054 DOI: 10.1021/jp504804n] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We present a comprehensive overview of our ongoing studies applying dc slice imaging in crossed molecular beams to probe the dynamics of chlorine atom reactions with polyatomic hydrocarbons. Our approach consists in measuring the full velocity-flux contour maps of the radical products using vacuum ultraviolet "soft" photoionization at 157 nm. Our overall goal is to extend the range of chemical dynamics investigations from simple triatomic or tetraatomic molecules to systematic investigations of a sequence of isomers or a homologous series of reactants of intermediate size. These experimental investigations are augmented by high-level ab initio calculations which, taken together, reveal trends in product energy and angular momentum partitioning and offer deep insight into the reaction mechanisms as a function of structure, bonding patterns, and kinematics. We explore these issues in alkanes, for which only direct reactive encounters are found, and in unsaturated hydrocarbons, for which an addition-elimination mechanism competes with direct abstraction. The results for alkene addition-elimination in particular suggest a new view of these reactions: The only pathway to HCl elimination is accessed by means of roaming excursions of the Cl atom from the strongly bound adduct.
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Affiliation(s)
- Baptiste Joalland
- Department of Chemistry, Wayne State University , Detroit, Michigan 48202, United States
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Estillore AD, Visger-Kiefer LM, Ghani TA, Suits AG. Dynamics of H and D abstraction in the reaction of Cl atom with butane-1,1,1,4,4,4-d6. Phys Chem Chem Phys 2011; 13:8433-40. [DOI: 10.1039/c1cp20137a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Estillore AD, Visger LM, Suits AG. Imaging the dynamics of chlorine atom reactions with alkenes. J Chem Phys 2010; 133:074306. [DOI: 10.1063/1.3473049] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Estillore AD, Visger LM, Suits AG. Crossed-beam dc slice imaging of chlorine atom reactions with pentane isomers. J Chem Phys 2010; 132:164313. [DOI: 10.1063/1.3414353] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
| | - Laura M. Visger
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
| | - Arthur G. Suits
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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