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Douglas KM, Lucas D, Walsh C, Blitz MA, Heard DE. Experimental and Theoretical Investigation of the Reaction of NH 2 with NO at Very Low Temperatures. J Phys Chem A 2023; 127:7205-7215. [PMID: 37589656 PMCID: PMC10476206 DOI: 10.1021/acs.jpca.3c03652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/24/2023] [Indexed: 08/18/2023]
Abstract
The first experimental study of the low-temperature kinetics of the gas-phase reaction between NH2 and NO has been performed. A pulsed laser photolysis-laser-induced fluorescence technique was used to create and monitor the temporal decay of NH2 in the presence of NO. Measurements were carried out over the temperature range of 24-106 K, with the low temperatures achieved using a pulsed Laval nozzle expansion. The negative temperature dependence of the reaction rate coefficient observed at higher temperatures in the literature continues at these lower temperatures, with the rate coefficient reaching 3.5 × 10-10 cm3 molecule-1 s-1 at T = 26 K. Ab initio calculations of the potential energy surface were combined with rate theory calculations using the MESMER software package in order to calculate and predict rate coefficients and branching ratios over a wide range of temperatures, which are largely consistent with experimentally determined literature values. These theoretical calculations indicate that at the low temperatures investigated for this reaction, only one product channel producing N2 + H2O is important. The rate coefficients determined in this study were used in a gas-phase astrochemical model. Models were run over a range of physical conditions appropriate for cold to warm molecular clouds (10 to 30 K; 104 to 106 cm-3), resulting in only minor changes (<1%) to the abundances of NH2 and NO at steady state. Hence, despite the observed increase in the rate at low temperatures, this mechanism is not a dominant loss mechanism for either NH2 or NO under dark cloud conditions.
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Affiliation(s)
| | - Daniel Lucas
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
| | - Catherine Walsh
- School
of Physics and Astronomy, University of
Leeds, Leeds LS2 9JT, U.K.
| | - Mark A. Blitz
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
- National
Centre for Atmospheric Science (NCAS), University
of Leeds, Leeds LS2 9JT, U.K.
| | - Dwayne E. Heard
- School
of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
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2
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Ziegler B, Rauhut G. Vibrational analysis of nitrosamine, a molecule with an almost constant potential along the inversion coordinate. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1522004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Benjamin Ziegler
- Institute for Theoretical Chemistry, University of Stuttgart, Stuttgart, Germany
| | - Guntram Rauhut
- Institute for Theoretical Chemistry, University of Stuttgart, Stuttgart, Germany
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3
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McCarthy MC, Lee KLK, Stanton JF. Detection and structural characterization of nitrosamide H 2NNO: A central intermediate in deNO x processes. J Chem Phys 2017; 147:134301. [PMID: 28987087 DOI: 10.1063/1.4992097] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The structure and bonding of H2NNO, the simplest N-nitrosamine, and a key intermediate in deNOx processes, have been precisely characterized using a combination of rotational spectroscopy of its more abundant isotopic species and high-level quantum chemical calculations. Isotopic spectroscopy provides compelling evidence that this species is formed promptly in our discharge expansion via the NH2 + NO reaction and is collisionally cooled prior to subsequent unimolecular rearrangement. H2NNO is found to possess an essentially planar geometry, an NNO angle of 113.67(5)°, and a N-N bond length of 1.342(3) Å; in combination with the derived nitrogen quadrupole coupling constants, its bonding is best described as an admixture of uncharged dipolar (H2N-N=O, single bond) and zwitterion (H2N+=N-O-, double bond) structures. At the CCSD(T) level, and extrapolating to the complete basis set limit, the planar geometry appears to represent the minimum of the potential surface, although the torsional potential of this molecule is extremely flat.
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Affiliation(s)
- Michael C McCarthy
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, Massachusetts 02138, USA
| | - Kin Long Kelvin Lee
- Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, USA and School of Engineering and Applied Sciences, Harvard University, 29 Oxford St., Cambridge, Massachusetts 02138, USA
| | - John F Stanton
- Department of Chemistry and Biochemistry, The University of Texas at Austin, 1 University Station A5300, Austin, Texas 78712-0165, USA
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Harding LB, Klippenstein SJ, Jasper AW. Separability of tight and roaming pathways to molecular decomposition. J Phys Chem A 2012; 116:6967-82. [PMID: 22671970 DOI: 10.1021/jp303581k] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent studies have questioned the separability of the tight and roaming mechanisms to molecular decomposition. We explore this issue for a variety of reactions including MgH(2) → Mg + H(2), NCN → CNN, H(2)CO → H(2) + CO, CH(3)CHO → CH(4) + CO, and HNNOH → N(2) + H(2)O. Our analysis focuses on the role of second-order saddle points in defining global dividing surfaces that encompass both tight and roaming first-order saddle points. The second-order saddle points define an energetic criterion for separability of the two mechanisms. Furthermore, plots of the differential contribution to the reactive flux along paths connecting the first- and second-order saddle points provide a dynamic criterion for separability. The minimum in the differential reactive flux in the neighborhood of the second-order saddle point plays the role of a mechanism divider, with the presence of a strong minimum indicating that the roaming and tight mechanisms are dynamically distinct. We show that the mechanism divider is often, but not always, associated with a second-order saddle point. For the formaldehyde and acetaldehyde reactions, we find that the minimum energy geometry on a conical intersection is associated with the mechanism divider for the tight and roaming processes. For HNNOH, we again find that the roaming and tight processes are dynamically separable but we find no intrinsic feature of the potential energy surface associated with the mechanism divider. Overall, our calculations suggest that roaming and tight mechanisms are generally separable over broad ranges of energy covering most kinetically relevant regimes.
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Affiliation(s)
- Lawrence B Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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5
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Wu YJ. Structure, stability, electron affinity, and electronic spectra of isomers of C6H. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2010.10.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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6
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Zhang F, Kim YS, Zhou L, Chang AHH, Kaiser RI. A crossed molecular beam study on the synthesis of the interstellar 2,4-pentadiynylidyne radical (HCCCCC). J Chem Phys 2009; 129:134313. [PMID: 19045096 DOI: 10.1063/1.2987366] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Crossed molecular beam experiments are performed to elucidate the synthesis of the 2,4-penta-diynylidyne [HCCCCC(X (2)Pi)] radical under single collision conditions--a crucial reaction intermediate to form polycyclic aromatic hydrocarbons and carbonaceous nanostructures in the interstellar medium and in combustion flames. The experiments demonstrate that the chemical dynamics of ground state carbon reacting with diacetylene [HCCCCH(X (1)Sigma(g)(+))] are indirect and proceed via addition of the electrophilic carbon atom to the pi electron density of the diacetylene molecule yielding ultimately the carbenelike HCCCCCH(X (3)Sigma(g)(-)) molecule. This intermediate fragments via hydrogen atom emission to yield the 2,4-pentadiynylidyne [HCCCCC(X (2)Pi)] radical. The chemical dynamics elucidated also allows us to predict that reaction of carbon atoms with polyynes of the generic formula H(C[triple bond]C)(n)H leads to the formation of hydrogen-terminated carbon clusters of the generic form HC(2n+1) in extreme environments. The acetylene-related reactivity and electronic structure of the diacetylene molecule also allow us to project that reactions of the diacetylene molecule with cyano and ethynyl radicals result in a stepwise extension of the carbon skeleton forming cyanodiacetylene (HCCCCCN) and triacetylene (HCCCCCCH) plus atomic hydrogen. These predictions open the door to extensive laboratory studies involving hitherto poorly understood reactions of the diacetylene molecule under single collision conditions.
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Affiliation(s)
- Fangtong Zhang
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822, USA
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Fernandez-Ramos A, Miller JA, Klippenstein SJ, Truhlar DG. Modeling the kinetics of bimolecular reactions. Chem Rev 2007; 106:4518-84. [PMID: 17091928 DOI: 10.1021/cr050205w] [Citation(s) in RCA: 393] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Antonio Fernandez-Ramos
- Departamento de Quimica Fisica, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain
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9
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Jacox ME, Thompson WE. Infrared spectra of NH2NO, NH2NO+, and NNOH+ and of the N2⋯H2O complex trapped in solid neon. J Chem Phys 2005; 123:64501. [PMID: 16122320 DOI: 10.1063/1.1993591] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
When a Ne:H2:N2O mixture is co-deposited at 4.3 K with a beam of neon atoms that have been excited in a microwave discharge, NH2NO+ is stabilized in sufficient concentration for detection of five of its vibrational fundamentals. Their assignments are supported by isotopic substitution studies and by the results of unrestricted B3LYP/cc-pVTZ calculations. Electron recombination results in the stabilization of NH2NO, for which the previously reported argon-matrix assignments are confirmed and extended. The OH-stretching fundamental of NNOH+ also is present in the spectrum of the initial sample deposit, but because of proton sharing with the neon matrix is shifted 43.3 cm(-1) from the gas-phase band center. The OD-stretching fundamental of NNOD+ is identified for the first time in the present study. An absorption at 2311.1 cm(-1) is contributed by the NN-stretching vibration of a complex of N2, probably with an ionic species. On prolonged visible and near-ultraviolet irradiation of the deposit, absorptions of the binary N2...H2O complex become increasingly prominent.
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Affiliation(s)
- Marilyn E Jacox
- Optical Technology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8441, USA.
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RRKM Theory and Its Implementation. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0069-8040(03)80004-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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11
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Schranz HW, Smith SC, Mebel AM, Lin SH. Prediction of absolute rate coefficients and product branching ratios for the C(3P)+allene reaction system. J Chem Phys 2002. [DOI: 10.1063/1.1506307] [Citation(s) in RCA: 7] [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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12
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Klippenstein SJ, Miller JA. From the Time-Dependent, Multiple-Well Master Equation to Phenomenological Rate Coefficients. J Phys Chem A 2002. [DOI: 10.1021/jp021175t] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen J. Klippenstein
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969
| | - James A. Miller
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969
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Marcy TP, Heard DE, Leone SR. Product Studies of Inelastic and Reactive Collisions of NH2 + NO: Effects of Vibrationally and Electronically Excited NH2†. J Phys Chem A 2002. [DOI: 10.1021/jp013997g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Timothy P. Marcy
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440
| | - Dwayne E. Heard
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440
| | - Stephen R. Leone
- JILA, National Institute of Standards and Technology and University of Colorado, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440
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