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Nguyen TL, Peeters J. The CH(X 2Π) + H 2O reaction: two transition state kinetics. Phys Chem Chem Phys 2021; 23:16142-16149. [PMID: 34296725 DOI: 10.1039/d1cp02234b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of ground state methylidyne (CH) with water vapor (H2O) is theoretically re-investigated using high-level coupled cluster computations in combination with semi-classical transition state theory (SCTST) and two-dimensional master equation simulations. Insertion of CH into a H-O bond of H2O over a submerged barrier via a well-skipping mechanism yielding solely H and CH2O is characterized. The reaction kinetics is effectively determined by the formation of a pre-reaction van der Waals complex (PRC, HC-OH2) and its subsequent isomerization to activated CH2OH in competition with PRC re-dissociation. The tunneling effects are found to be minor, while variational effects in the PRC → CH2OH step are negligible. The calculated rate coefficient k(T) is nearly pressure-independent, but strongly depends on temperature with pronounced down-up behavior: a high value of 2 × 10-10 cm3 s-1 at 50 K, followed by a fairly steep decrease down to 8 × 10-12 cm3 s-1 at 900 K, but increasing again to 5 × 10-11 cm3 s-1 at 3500 K. Over the T-range of this work, k(T) can be expressed as: k(T, P = 0) = 2.31 × 10-11 (T/300 K)-1.615 exp(-38.45/T) cm3 s-1 for T = 50-400 K k(T, P = 0) = 1.15 × 10-12 (T/300 K)0.8637 exp(892.6/T) cm3 s-1 for T = 400-1000 K k(T, P = 0) = 4.57 × 10-15 (T/300 K)3.375 exp(3477.4/T) cm3 s-1 for T = 1000-3500 K.
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Affiliation(s)
- Thanh Lam Nguyen
- Quantum Theory Project, Department of Chemistry and Physics, University of Florida, Gainesville, FL 32611, USA.
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Pearce BKD, Ayers PW, Pudritz RE. CRAHCN-O: A Consistent Reduced Atmospheric Hybrid Chemical Network Oxygen Extension for Hydrogen Cyanide and Formaldehyde Chemistry in CO 2-, N 2-, H 2O-, CH 4-, and H 2-Dominated Atmospheres. J Phys Chem A 2020; 124:8594-8606. [PMID: 32961050 DOI: 10.1021/acs.jpca.0c06804] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Hydrogen cyanide (HCN) and formaldehyde (H2CO) are key precursors to biomolecules such as nucleobases and amino acids in planetary atmospheres. However, many reactions which produce and destroy these species in atmospheres containing CO2 and H2O are still missing from the literature. We use a quantum chemistry approach to find these missing reactions and calculate their rate coefficients using canonical variational transition state theory and Rice-Ramsperger-Kassel-Marcus/master equation theory at the BHandHLYP/aug-cc-pVDZ level of theory. We calculate the rate coefficients for 126 total reactions and validate our calculations by comparing with experimental data in the 39% of available cases. Our calculated rate coefficients are most frequently within a factor of 2 of experimental values and generally always within an order of magnitude of these values. We discover 45 previously unknown reactions and identify 6 from this list that are most likely to dominate H2CO and HCN production and destruction in planetary atmospheres. We highlight 1O + CH3 → H2CO + H as a new key source and H2CO + 1O → HCO + OH as a new key sink, for H2CO in upper planetary atmospheres. In this effort, we develop an oxygen extension to our consistent reduced atmospheric hybrid chemical network (CRAHCN-O), building off our previously developed network for HCN production in N2-, CH4-, and H2-dominated atmospheres (CRAHCN). This extension can be used to simulate both HCN and H2CO production in atmospheres dominated by any of CO2, N2, H2O, CH4, and H2.
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Affiliation(s)
- Ben K D Pearce
- Origins Institute and Department of Physics and Astronomy, McMaster University, ABB 241, 1280 Main Street, Hamilton, Ontario L8S 4M1, Canada
| | - Paul W Ayers
- Origins Institute and Department of Chemistry and Chemical Biology, McMaster University, ABB 156, 1280 Main Street, Hamilton, Ontario L8S 4M1, Canada
| | - Ralph E Pudritz
- Origins Institute and Department of Physics and Astronomy, McMaster University, ABB 241, 1280 Main Street, Hamilton, Ontario L8S 4M1, Canada
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Mazarei E, Hosein Mousavipour S. Theoretical Study on the Dynamics and Kinetics of the Reaction of CH 2OH with OH. J Phys Chem A 2018; 122:9761-9777. [PMID: 30508487 DOI: 10.1021/acs.jpca.8b09621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The stochastic one-dimensional chemical master equation (CME) simulation method was used to investigate the dynamics of the reaction of CH2OH with OH. A multiwell multichannel potential energy surface (PES) was constructed at the CCSD(T)/Aug-cc-pVTZ//CBS-QB3 and QCISD(T)/Aug-cc-pVTZ//CBS-QB3 levels of theory. The constructed PES consisted of three chemically activated intermediates and two van der Waals complexes. The fractional population analysis unraveled the role of the energized intermediates and van der Waals complexes in the early stages of this complex reaction. The CME calculations provided the phenomenological rate constants through analysis of the eigenvalues and eigenvectors of collision matrices while Leonard-Jones potential was used to model the collisions. The CME results indicated that CH2O and H2O were the major products, in accordance with the literature. Also, the findings declared the temperature and pressure independence of the reaction over a wide range of temperature (250 to 2400 K) and pressure (0.1 to 7 atm). Furthermore, the efficiency of tunneling on the hydrogen transfer isomerization reaction of trans-HCOH to CH2O was confirmed over the temperature range of 250 to 3000 K. The rate constants for different reaction channels are reported.
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Affiliation(s)
- Elham Mazarei
- Department of Chemistry, College of Science , Shiraz University , Shiraz , Iran
| | - S Hosein Mousavipour
- Department of Chemistry, College of Science , Shiraz University , Shiraz , Iran.,Department of Chemistry, Faculty of Science , Sultan Qaboos University , Muscat , Sultanate of Oman
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Mazarei E, Mousavipour SH. A Theoretical Study on the Dynamics of the Reaction of CH Radicals with Water. J Phys Chem A 2017; 121:8033-8047. [DOI: 10.1021/acs.jpca.7b05504] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elham Mazarei
- Department of Chemistry,
College of Science, Shiraz University, Shiraz, Iran
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Daranlot J, Hu X, Xie C, Loison JC, Caubet P, Costes M, Wakelam V, Xie D, Guo H, Hickson KM. Low temperature rate constants for the N(4S) + CH(X2Πr) reaction. Implications for N2 formation cycles in dense interstellar clouds. Phys Chem Chem Phys 2013; 15:13888-96. [DOI: 10.1039/c3cp52535j] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hu R, Zhang Q, Chen Y. Reaction of C2(a Π3u) with methanol: Temperature dependence and deuterium isotope effect. J Chem Phys 2010; 133:114306. [DOI: 10.1063/1.3480395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Fockenberg C, Weston RE, Muckerman JT. Product Study of the Reaction of CH3 with OH Radicals at Low Pressures and Temperatures of 300 and 612 K†. J Phys Chem B 2005; 109:8415-27. [PMID: 16851988 DOI: 10.1021/jp045792o] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The product distribution for the title reaction was studied using our time-of-flight mass spectrometer (TOFMS) connected to a tubular flow reactor. The methyl and hydroxyl radicals were produced by an excimer laser pulse (lambda = 193 nm) photolyzing acetone and nitrous oxide in the presence of excess water or hydrogen. Helium was used as the bath gas; the total density was held constant at 1.2 x 10(17) cm(-3). At 300 K the observations were consistent with singlet methylene ((1)CH(2)) and water as the main product channel with a small contribution of methanol. In contrast, at about 610 K three channels-formaldehyde isomers and methanol in addition to (1)CH(2) + H(2)O-are formed with similar yields. When acetone-d(6) was used, the production of both CHDO and CD(2)O was observed, indicating that two different formaldehyde-producing channels are operating simultaneously. These experimental results are compared with RRKM and master equation calculations on the basis of the properties of the methanol potential energy surface from a recent ab initio study.
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Affiliation(s)
- Christopher Fockenberg
- Chemistry Department 555A, Brookhaven National Laboratory, P. O. Box 5000, Upton, New York 11973-5000, USA
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Gravestock T, Blitz MA, Heard DE. Kinetics study of the reaction of iodine monoxide radicals with dimethyl sulfide. Phys Chem Chem Phys 2005; 7:2173-81. [DOI: 10.1039/b502989a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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McKee K, Blitz MA, Hughes KJ, Pilling MJ, Qian HB, Taylor A, Seakins PW. H Atom Branching Ratios from the Reactions of CH with C2H2, C2H4, C2H6, and neo-C5H12 at Room Temperature and 25 Torr. J Phys Chem A 2003. [DOI: 10.1021/jp021613w] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Kenneth McKee
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Mark A. Blitz
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Kevin J. Hughes
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | | | - Hai-Bo Qian
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Andrew Taylor
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
| | - Paul W. Seakins
- School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K
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Marcy TP, Reid JP, Qian CXW, Leone SR. Addition-insertion-elimination reactions of O(3P) with halogenated iodoalkanes producing HF(v) and HCl(v). J Chem Phys 2001. [DOI: 10.1063/1.1337800] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Blitz M, Pesa M, Pilling M, Seakins P. Vibrational relaxation of the CH(D)(X2Π, v=1,2) radical by helium and argon: evidence for a curve crossing mechanism. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00409-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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