51
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Van Geem KM, Pyl SP, Marin GB, Harper MR, Green WH. Accurate High-Temperature Reaction Networks for Alternative Fuels: Butanol Isomers. Ind Eng Chem Res 2010. [DOI: 10.1021/ie1005349] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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52
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Thomas PS, Miller TA. Cavity ringdown spectroscopy of the NIR A∼-X∼ electronic transition of allyl peroxy radical (H2CCH–CH2OO·). Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.03.073] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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53
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Newby JJ, Müller CW, Liu CP, Zwier TS. Probing E/Z Isomerization on the C10H8 Potential Energy Surface with Ultraviolet Population Transfer Spectroscopy. J Am Chem Soc 2010; 132:1611-20. [PMID: 20067293 DOI: 10.1021/ja908103u] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Josh J. Newby
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
| | - Christian W. Müller
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
| | - Ching-Ping Liu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
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54
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Troy TP, Nakajima M, Chalyavi N, Clady RGCR, Nauta K, Kable SH, Schmidt TW. Identification of the Jet-Cooled 1-Indanyl Radical by Electronic Spectroscopy. J Phys Chem A 2009; 113:10279-83. [DOI: 10.1021/jp905831m] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Tyler P. Troy
- School of Chemistry, University of Sydney, NSW 2006, Australia
| | | | - Nahid Chalyavi
- School of Chemistry, University of Sydney, NSW 2006, Australia
| | | | - Klaas Nauta
- School of Chemistry, University of Sydney, NSW 2006, Australia
| | - Scott H. Kable
- School of Chemistry, University of Sydney, NSW 2006, Australia
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55
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Reilly NJ, Nakajima M, Troy TP, Chalyavi N, Duncan KA, Nauta K, Kable SH, Schmidt TW. Spectroscopic Identification of the Resonance-Stabilized cis- and trans-1-Vinylpropargyl Radicals. J Am Chem Soc 2009; 131:13423-9. [DOI: 10.1021/ja904521c] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Neil J. Reilly
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | | | - Tyler P. Troy
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Nahid Chalyavi
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Kieran A. Duncan
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Klaas Nauta
- School of Chemistry, The University of Sydney, NSW 2006, Australia
| | - Scott H. Kable
- School of Chemistry, The University of Sydney, NSW 2006, Australia
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56
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Frankcombe TJ, Smith SC. Numerical solution methods for large, difficult kinetic master equations. Theor Chem Acc 2009. [DOI: 10.1007/s00214-009-0623-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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57
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Goldsmith CF, Ismail H, Green WH. Pressure and Temperature Dependence of the Reaction of Vinyl Radical with Alkenes III: Measured Rates and Predicted Product Distributions for Vinyl + Butene. J Phys Chem A 2009; 113:13357-71. [DOI: 10.1021/jp9042039] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- C. Franklin Goldsmith
- Departments of Chemical Engineering and Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Huzeifa Ismail
- Departments of Chemical Engineering and Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - William H. Green
- Departments of Chemical Engineering and Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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58
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Sharma S, Green WH. Computed Rate Coefficients and Product Yields for c-C5H5 + CH3 → Products. J Phys Chem A 2009; 113:8871-82. [DOI: 10.1021/jp900679t] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sandeep Sharma
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - William H. Green
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
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59
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Vasiliou A, Nimlos MR, Daily JW, Ellison GB. Thermal Decomposition of Furan Generates Propargyl Radicals. J Phys Chem A 2009; 113:8540-7. [DOI: 10.1021/jp903401h] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- AnGayle Vasiliou
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
| | - Mark R. Nimlos
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
| | - John W. Daily
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, and Center for Combustion and Environmental Research, Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309-0427
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60
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Huynh LK, Zhang HR, Zhang S, Eddings E, Sarofim A, Law ME, Westmoreland PR, Truong TN. Kinetics of enol formation from reaction of OH with propene. J Phys Chem A 2009; 113:3177-85. [PMID: 19271758 DOI: 10.1021/jp808050j] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Kinetics of enol generation from propene has been predicted in an effort to understand the presence of enols in flames. A potential energy surface for reaction of OH with propene was computed by CCSD(T)/cc-pVDZ//B3LYP/cc-pVTZ calculations. Rate constants of different product channels and branching ratios were then calculated using the Master Equation formulation (J. Phys. Chem. A 2006, 110, 10528). Of the two enol products, ethenol is dominant over propenol, and its pathway is also the dominant pathway for the OH + propene addition reactions to form bimolecular products. In the temperature range considered, hydrogen abstraction dominated propene + OH consumption by a branching ratio of more than 90%. Calculated rate constants of enol formation were included in the Utah Surrogate Mechanism to model the enol profile in a cyclohexane premixed flame. The extended model shows consistency with experimental data and gives 5% contribution of ethenol formation from OH + propene reaction, the rest coming from ethene + OH.
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Affiliation(s)
- Lam K Huynh
- Henry Eyring Center for Theoretical Chemistry, Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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61
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Reilly NJ, Nakajima M, Gibson BA, Schmidt TW, Kable SH. Laser-induced fluorescence and dispersed fluorescence spectroscopy of jet-cooled 1-phenylpropargyl radical. J Chem Phys 2009; 130:144313. [DOI: 10.1063/1.3110682] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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62
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Papas BN, Schuurman MS, Yarkony DR. The simulated photoelectron spectrum of 1-propynide. J Chem Phys 2009; 130:064306. [PMID: 19222277 DOI: 10.1063/1.3072621] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The negative ion photoelectron spectrum of 1-propynide is computed by employing the multimode vibronic coupling approach. A three-state quasidiabatic Hamiltonian, H(d), is reported, which accurately represents the ab initio determined equilibrium geometries and harmonic frequencies of the ground X (2)A(1) state as well as the low-lying Jahn-Teller distorted components of the A (2)E excited state. It also reproduces both the minimum energy crossing point (MECP) on the symmetry-required (2)E(x)-(2)E(y) conical intersection seam and the MECP on the same symmetry (2)A(1)-(2)E(x) conical intersection seam. H(d) includes all terms through second order in internal coordinates for both the diagonal and off-diagonal blocks. It is centered at the (2)E(x)-(2)E(y) MECP and is determined using ab initio gradients and derivative couplings near both the (2)E(x)-(2)E(y) MECP and the X (2)A(1) equilibrium geometry. This construction is enabled by a recently reported normal equation based algorithm. The C(3v) symmetry of the system is used to significantly reduce the computational cost of the ab initio treatment. This H(d) is then expressed in a vibronic basis that is chosen for its ability to reduce the dimension of the vibronic expansion. The vibronic Hamiltonian matrix is diagonalized to obtain a negative ion photoelectron spectrum for 1-propynide-h(3). The determined spectrum compares favorably with previous spectroscopic results. In particular, the lines attributable to the (2)E state are found to be much weaker than those corresponding to the (2)A(1) state of 1-propynyl. This diminution of the (2)E state is attributable principally to the (2)E(x)-(2)A(1) conical intersection rather than an intrinsically small electronic transition moment for the production of the (2)E state.
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Affiliation(s)
- Brian N Papas
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA
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63
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Newby JJ, Liu CP, Müller CW, Zwier TS. Jet-cooled vibronic spectroscopy of potential intermediates along the pathway to PAH: phenylcyclopenta-1,3-diene. Phys Chem Chem Phys 2009; 11:8316-29. [DOI: 10.1039/b903827b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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64
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Selby TM, Meloni G, Goulay F, Leone SR, Fahr A, Taatjes CA, Osborn DL. Synchrotron Photoionization Mass Spectrometry Measurements of Kinetics and Product Formation in the Allyl Radical (H2CCHCH2) Self-Reaction. J Phys Chem A 2008; 112:9366-73. [DOI: 10.1021/jp802330k] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Talitha M. Selby
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Giovanni Meloni
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Fabien Goulay
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Stephen R. Leone
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Askar Fahr
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - Craig A. Taatjes
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
| | - David L. Osborn
- Sandia National Laboratories, Combustion Research Facility, MS 9055, Livermore, California 94551-0969, Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, and Department of Chemistry, Howard University, Washington, D.C. 20059
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65
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Reilly NJ, Kokkin DL, Nakajima M, Nauta K, Kable SH, Schmidt TW. Spectroscopic Observation of the Resonance-Stabilized 1-Phenylpropargyl Radical. J Am Chem Soc 2008; 130:3137-42. [DOI: 10.1021/ja078342t] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Neil J. Reilly
- School of Chemistry, University of Sydney, NSW 2006, Australia
| | | | | | - Klaas Nauta
- School of Chemistry, University of Sydney, NSW 2006, Australia
| | - Scott H. Kable
- School of Chemistry, University of Sydney, NSW 2006, Australia
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66
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Newby JJ, Stearns JA, Liu CP, Zwier TS. Photochemical and Discharge-Driven Pathways to Aromatic Products from 1,3-Butadiene. J Phys Chem A 2007; 111:10914-27. [PMID: 17929788 DOI: 10.1021/jp0752567] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Josh J. Newby
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
| | - Jaime A. Stearns
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
| | - Ching-Ping Liu
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
| | - Timothy S. Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084
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67
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Harding LB, Klippenstein SJ, Georgievskii Y. On the Combination Reactions of Hydrogen Atoms with Resonance-Stabilized Hydrocarbon Radicals. J Phys Chem A 2007; 111:3789-801. [PMID: 17388384 DOI: 10.1021/jp0682309] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Procedures for accurately predicting the kinetics of H atom associations with resonance stabilized hydrocarbon radicals are described and applied to a series of reactions. The approach is based on direct CASPT2/cc-pvdz evaluations of the orientation dependent interaction energies within variable reaction coordinate transition state theory. One-dimensional corrections to the interaction energies are estimated from a CASPT2/aug-cc-pvdz minimum energy path (MEP) on the specific reaction of interest and a CASPT2/aug-cc-pvtz MEP for the H + CH3 reaction. A dynamical correction factor of 0.9 is also applied. For the H + propargyl, allyl, cyclopentadienyl, and benzyl reactions, where the experimental values appear to be quite well determined, theory and experiment agree to within their error bars. Predictions are also made for the combinations with triplet propargylene, CH2CCCH, CH3CCCH2, CH2CHCCH2, CH3CHCCH, cyclic-C4H5, CH2CCCCH, and CHCCHCCH.
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Affiliation(s)
- Lawrence B Harding
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
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68
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Georgievskii Y, Miller JA, Klippenstein SJ. Association rate constants for reactions between resonance-stabilized radicals: C3H3 + C3H3, C3H3 + C3H5, and C3H5 + C3H5. Phys Chem Chem Phys 2007; 9:4259-68. [PMID: 17687474 DOI: 10.1039/b703261g] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reactions between resonance-stabilized radicals play an important role in combustion chemistry. The theoretical prediction of rate coefficients and product distributions for such reactions is complicated by the fact that the initial complex-formation steps and some dissociation steps are barrierless. In this paper direct variable reaction coordinate transition state theory (VRC-TST) is used to predict accurately the association rate constants for the self and cross reactions of propargyl and allyl radicals. For each reaction, a set of multifaceted dividing surfaces is used to account for the multiple possible addition channels. Because of their resonant nature the geometric relaxation of the radicals is important. Here, the effect of this relaxation is explicitly calculated with the UB3LYP/cc-pvdz method for each mutual orientation encountered in the configurational integrals over the transition state dividing surfaces. The final energies are obtained from CASPT2/cc-pvdz calculations with all pi-orbitals in the active space. Evaluations along the minimum energy path suggest that basis set corrections are negligible. The VRC-TST approach was also used to calculate the association rate constant and the corresponding number of states for the C(6)H(5) + H --> C(6)H(6) exit channel of the C(3)H(3) + C(3)H(3) reaction, which is also barrierless. For this reaction, the interaction energies were evaluated with the CASPT2(2e,2o)/cc-pvdz method and a 1-D correction is included on the basis of CAS+1+2+QC/aug-cc-pvtz calculations for the CH(3) + H reference system. For the C(3)H(3) + C(3)H(3) reaction, the VRC-TST results for the energy and angular momentum resolved numbers of states in the entrance channels and in the C(6)H(5) + H exit channel are incorporated in a master equation simulation to determine the temperature and pressure dependence of the phenomenological rate coefficients. The rate constants for the C(3)H(3) + C(3)H(3) and C(3)H(5) + C(3)H(5) self-reactions compare favorably with the available experimental data. To our knowledge there are no experimental rate data for the C(3)H(3) + C(3)H(5) reaction.
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Affiliation(s)
- Yuri Georgievskii
- Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551-0969, USA
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69
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Kislov VV, Nguyen TL, Mebel AM, Lin SH, Smith SC. Photodissociation of benzene under collision-free conditions: an ab initio/Rice-Ramsperger-Kassel-Marcus study. J Chem Phys 2006; 120:7008-17. [PMID: 15267601 DOI: 10.1063/1.1676275] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The ab initio/Rice-Ramsperger-Kassel-Marcus (RRKM) approach has been applied to investigate the photodissociation mechanism of benzene at various wavelengths upon absorption of one or two UV photons followed by internal conversion into the ground electronic state. Reaction pathways leading to various decomposition products have been mapped out at the G2M level and then the RRKM and microcanonical variational transition state theories have been applied to compute rate constants for individual reaction steps. Relative product yields (branching ratios) for C(6)H(5)+H, C(6)H(4)+H(2), C(4)H(4)+C(2)H(2), C(4)H(2)+C(2)H(4), C(3)H(3)+C(3)H(3), C(5)H(3)+CH(3), and C(4)H(3)+C(2)H(3) have been calculated subsequently using both numerical integration of kinetic master equations and the steady-state approach. The results show that upon absorption of a 248 nm photon dissociation is too slow to be observable in molecular beam experiments. In photodissociation at 193 nm, the dominant dissociation channel is H atom elimination (99.6%) and the minor reaction channel is H(2) elimination, with the branching ratio of only 0.4%. The calculated lifetime of benzene at 193 nm is about 11 micros, in excellent agreement with the experimental value of 10 micros. At 157 nm, the H loss remains the dominant channel but its branching ratio decreases to 97.5%, while that for H(2) elimination increases to 2.1%. The other channels leading to C(3)H(3)+C(3)H(3), C(5)H(3)+CH(3), C(4)H(4)+C(2)H(2), and C(4)H(3)+C(2)H(3) play insignificant role but might be observed. For photodissociation upon absorption of two UV photons occurring through the neutral "hot" benzene mechanism excluding dissociative ionization, we predict that the C(6)H(5)+H channel should be less dominant, while the contribution of C(6)H(4)+H(2) and the C(3)H(3)+C(3)H(3), CH(3)+C(5)H(3), and C(4)H(3)+C(2)H(3) radical channels should significantly increase.
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Affiliation(s)
- V V Kislov
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10764, Taiwan
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70
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Kwon LK, Nam MJ, Youn SE, Joo SK, Lee H, Choi JH. Crossed-beam radical-radical reaction dynamics of O(3P)+C3H3-->H(2S)+C3H2O. J Chem Phys 2006; 124:204320. [PMID: 16774345 DOI: 10.1063/1.2201996] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The radical-radical oxidation reaction, O(3P)+C3H3 (propargyl)-->H(2S)+C3H2O (propynal), was investigated using vacuum-ultraviolet laser-induced fluorescence spectroscopy in a crossed-beam configuration, together with ab initio and statistical calculations. The barrierless addition of O(3P) to C3H3 is calculated to form energy-rich addition complexes on the lowest doublet potential energy surface, which subsequently undergo direct decomposition steps leading to the major reaction products, H+C3H(2)O (propynal). According to the nascent H-atom Doppler-profile analysis, the average translational energy of the products and the fraction of the average transitional energy to the total available energy were determined to be 5.09+/-0.36 kcal/mol and 0.077, respectively. On the basis of a comparison with statistical prior calculations, the reaction mechanism and the significant internal excitation of the polyatomic propynal product can be rationalized in terms of the formation of highly activated, short-lived addition-complex intermediates and the adiabaticity of the excess available energy along the reaction coordinate.
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Affiliation(s)
- Lee-Kyoung Kwon
- Department of Chemistry and Center for Electro- and Photo-Responsive Molecules, Korea University, 1, Anam-dong, Seoul 136-701, Korea
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71
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Selby TM, Das A, Bekele T, Lee HD, Zwier TS. Conformation-specific spectroscopy of 3-benzyl-1,5-hexadiyne. J Phys Chem A 2005; 109:8497-506. [PMID: 16834246 DOI: 10.1021/jp052923s] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
3-Benzyl-1,5-hexadiyne (BHD) was studied by a combination of methods, including resonance-enhanced-two-photon ionization, UV-UV hole-burning spectroscopy, resonant ion-dip infrared spectroscopy, and rotational band contour analysis. There are five conformations of BHD observed in the expansion with their 1<-- S0 origins occurring at 37520, 37565, 37599, 37605, and 37631 cm(-1). DFT calculations predict six low energy conformations. Conformational assignments have been made by comparison of the experimental infrared spectra in the alkyl and acetylenic CH stretch region to DFT vibrational frequency and infrared intensity calculations. Rotational band contours provided further confirmation of these assignments. The electronic origin shifts of BHD compare favorably to the electronic origin shifts of 5-phenyl-1-pentyne with the exception of one conformation. This conformation is unique in that it is the only structure with both acetylenic groups in the gauche position over the ring. This gauche-gauche conformation exhibits a perpendicular (b-type) transition and produces extensive vibronic coupling reminiscent of symmetric monosubstituted benzenes.
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Affiliation(s)
- Talitha M Selby
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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72
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Tang W, Tranter RS, Brezinsky K. Isomeric Product Distributions from the Self-Reaction of Propargyl Radicals. J Phys Chem A 2005; 109:6056-65. [PMID: 16833941 DOI: 10.1021/jp050640u] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have investigated the isomeric C6H6 product distributions of the self-reaction of propargyl (C3H3) radicals at two nominal pressures of 25 and 50 bar over the temperature range 720-1350 K. Experiments were performed using propargyl iodide as the radical precursor in a high-pressure single-pulse shock tube with a residence time of 1.6-2.0 ms. The relative yields of the C6H6 products are strongly temperature dependent, and the main products are 1,5-hexadiyne (15HD), 1,2-hexadiene-5-yne (12HD5Y), 3,4-dimethylenecyclobutene (34DMCB), 2-ethynyl-1,3-butadiene (2E13BD), fulvene, and benzene, with the minor products being cis- and trans-1,3-hexadiene-5-yne (13HD5Y). 1,2,4,5-Hexatetraene (1245HT) was observed below 750 K but the concentrations were too low to be quantified. The experimentally determined entry branching ratios are: 44% 15HD, 38% 12HD5Y, and 18% 1245HT, which is efficiently converted to 34DMCB. Following the initial recombination step, various C6H6 isomers are formed by thermal rearrangement. The experimentally observed concentrations for the C6H6 species are in good agreement with earlier experiments on 15HD thermal rearrangement.
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Affiliation(s)
- Weiyong Tang
- Department of Mechanical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois, 60607, USA
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73
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Selby TM, Clarkson JR, Mitchell D, Fitzpatrick JAJ, Lee HD, Pratt DW, Zwier TS. Isomer-Specific Spectroscopy and Conformational Isomerization Energetics ofo-,m-, andp-Ethynylstyrenes. J Phys Chem A 2005; 109:4484-96. [PMID: 16833784 DOI: 10.1021/jp050858g] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The infrared and ultraviolet spectroscopy of o-, m-, and p-ethynylstyrene isomers (oES, mES, and pES) were studied by a combination of methods, including resonance-enhanced two-photon ionization (R2PI), UV-UV hole-burning spectroscopy (UVHB), resonant ion-dip infrared spectroscopy (RIDIRS), and rotationally resolved fluorescence excitation spectroscopy. In addition, the newly developed method of stimulated emission pumping-population transfer spectroscopy (SEP-PTS) was used to determine the energy threshold to conformational isomerization in m-ethynylstyrene. The S(1) <-- S(0) origin transitions of oES and pES occur at 32 369 and 33 407 cm(-1), respectively. In mES, the cis and trans conformations are calculated to be close in energy. In the R2PI spectrum of mES, the two most prominent peaks (32672 and 32926 cm(-1)) were confirmed by UVHB spectroscopy to be S(1) <-- S(0) origins of these two conformers. The red-shifted conformer was identified as the cis structure by least-squares fitting of the rotationally resolved fluorescence excitation spectrum of the origin band. There are also two possible conformations in oES, but transitions due to only one were observed experimentally, as confirmed by UVHB spectroscopy. Density functional theory calculations (B3LYP/6-31+G) predict that the cis-ortho conformer, in which the substituents point toward each other, is about 8 kJ/mol higher in energy than the trans-ortho isomer, and should only be about 5% of the room temperature population of oES. Ground-state infrared spectra in the C-H stretch region (3000-3300 cm(-1)) of each isomer were obtained with RIDIRS. In all three structural isomers, the acetylenic C-H stretch fundamental was split by Fermi resonance. Infrared spectra were also recorded in the excited electronic state, using a UV-IR-UV version of RIDIR spectroscopy. In all three isomers the acetylenic C-H stretch fundamental was unshifted from the ground state, but no Fermi resonance was seen. The first observed and last unobserved transitions in the SEP-PT spectrum were used to place lower and upper bounds on the barrier to cis --> trans isomerization in m-ethynylstyrene of 990-1070 cm(-1). Arguments are given for the lack of a kinetic shift in the measurement. The analogous trans --> cis barrier is in the same range (989-1065 cm(-1)), indicating that the relative energies of the zero-point levels of the two isomers are (E(ZPL)(cis) - E(ZPL)(trans))= -75 to +81 cm(-1). Both the barrier heights and relative energies of the minima are close to those determined by DFT (Becke3LYP/6-31+G) calculations.
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Affiliation(s)
- Talitha M Selby
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, USA
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74
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Yu HG, Muckerman JT. Ab Initio and Direct Dynamics Studies of the Reaction of Singlet Methylene with Acetylene and the Lifetime of the Cyclopropene Complex. J Phys Chem A 2005; 109:1890-6. [PMID: 16833521 DOI: 10.1021/jp045049w] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The energetics of the (1)CH(2) + C(2)H(2) --> H + C(3)H(3) reaction are accurately calculated using an extrapolated coupled-cluster/complete basis set (CBS) method based on the cc-pVDZ, cc-pVTZ, and cc-pVQZ basis sets. The reaction enthalpy (0 K) is predicted to be -20.33 kcal/mol. This reaction has no classical barrier in either the entrance or exit channel. However, there are several stable intermediates-cyclopropene (c-C(3)H(4)), allene (CH(2)CCH(2)), and propyne (CH(3)CCH)-along the minimum energy path. These intermediates with zero-point energy corrections lie below the reactants by 87.11 (c-C(3)H(4)), 109.69 (CH(2)CCH(2)), and 110.78 kcal/mol (CH(3)CCH). The vibrationally adiabatic ground-state (VAG) barrier height for c-C(3)H(4) isomerization to allene is obtained as 45.2 kcal/mol, and to propyne as 37.2 kcal/mol. In addition, the (1)CH(2) + C(2)H(2) reaction is investigated utilizing the dual-level "scaling all correlation" (SAC) ab initio method of Truhlar et al., i.e., the UCCSD(SAC)/cc-pVDZ theory. Results show that the reaction occurs via long-lived complexes. The lifetime of the cyclopropene intermediate is obtained as 3.2 +/- 0.4 ps. It is found that the intermediate propyne can be formed directly from reactants through the insertion of (1)CH(2) into a C-H bond of C(2)H(2). However, compared to the major mechanism in which the propyne is produced through a ring-opening of the cyclopropene complex, this reaction pathway is much less favorable. Finally, the theoretical thermal rate constant exhibits a negative temperature dependence, which is in excellent agreement with the previous results. The temperature dependence is consistent with the earlier RRKM results but weaker than the experimental observations at high temperatures.
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Affiliation(s)
- Hua-Gen Yu
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973-5000, USA
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75
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Wheeler SE, Allen WD, Schaefer HF. Thermochemistry of disputed soot formation intermediates C4H3 and C4H5. J Chem Phys 2004; 121:8800-13. [PMID: 15527344 DOI: 10.1063/1.1787496] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Accurate isomeric energy differences and standard enthalpies of formation for disputed intermediates in soot formation, C(4)H(3) and C(4)H(5), have been determined through systematic extrapolations of ab initio energies. Electron correlation has been included through second-order Z-averaged perturbation theory (ZAPT2), and spin-restricted, open-shell coupled-cluster methods through triple excitations [ROCCSD, ROCCSD(T), and ROCCSDT] utilizing the correlation-consistent hierarchy of basis sets, cc-pVXZ (X = D, T, Q, 5, and 6), followed by extrapolations to the complete basis set limit via the focal point method of Allen and co-workers. Reference geometries were fully optimized at the ROCCSD(T) level with a TZ(2d1f,2p1d) basis set. Our analysis finds that the resonance-stabilized i-C(4)H(3) and i-C(4)H(5) isomers lie 11.8 and 10.7 kcal mol(-1) below E-n-C(4)H(3) and E-n-C(4)H(5), respectively, several kcal mol(-1) (more, less) than reported in recent (diffusion Monte Carlo, B3LYP density-functional) studies. Moreover, in these systems Gaussian-3 (G3) theory suffers from large spin contamination in electronic wave functions, poor reference geometries, and anomalous vibrational frequencies, but fortuitous cancellation of these sizable errors leads to isomerization energies apparently accurate to 1 kcal mol(-1). Using focal-point extrapolations for isodesmic reactions, we determine the enthalpies of formation (delta(f)H(0) (composite function)) for i-C(4)H(3), Z-n-C(4)H(3), E-n-C(4)H(3), i-C(4)H(5), Z-n-C(4)H(5), and E-n-C(4)H(5) to be 119.0, 130.8, 130.8, 78.4, 89.7, and 89.1 kcal mol(-1), respectively. These definitive values remove any remaining uncertainty surrounding the thermochemistry of these isomers in combustion models, allowing for better assessment of whether even-carbon pathways contribute to soot formation.
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Affiliation(s)
- Steven E Wheeler
- Center for Computational Chemistry, University of Georgia, Athens, Georgia 30602-2525, USA
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76
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Davis HF, Shu J, Peterka DS, Ahmed M. Crossed beams study of the reaction 1CH2+C2H2→C3H3+H. J Chem Phys 2004; 121:6254-7. [PMID: 15446918 DOI: 10.1063/1.1785152] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The reaction of electronically excited singlet methylene (1CH2) with acetylene (C2H2) was studied using the method of crossed molecular beams at a mean collision energy of 3.0 kcal/mol. The angular and velocity distributions of the propargyl radical (C3H3) products were measured using single photon ionization (9.6 eV) at the advanced light source. The measured distributions indicate that the mechanism involves formation of a long-lived C3H4 complex followed by simple C-H bond fission producing C3H3+H. This work, which is the first crossed beams study of a reaction involving an electronically excited polyatomic molecule, demonstrates the feasibility of crossed molecular beam studies of reactions involving 1CH2.
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Affiliation(s)
- H Floyd Davis
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853-1301, USA
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77
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Tranter RS, Tang W, Anderson KB, Brezinsky K. Shock Tube Study of Thermal Rearrangement of 1,5-Hexadiyne over Wide Temperature and Pressure Regime. J Phys Chem A 2004. [DOI: 10.1021/jp037310z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Robert S. Tranter
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Weiyong Tang
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Ken B. Anderson
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - Kenneth Brezinsky
- Departments of Mechanical Engineering and Chemical Engineering, University of Illinois at Chicago, 842 West Taylor Street, M/C 251, Chicago, Illinois 60607, and Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
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78
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Lee H, Joo SK, Kwon LK, Choi JH. A combined crossed beam and theoretical investigation of O(3P)+C3H3→C3H2+OH. J Chem Phys 2004; 120:2215-24. [PMID: 15268360 DOI: 10.1063/1.1636458] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The radical-radical reaction dynamics of ground-state atomic oxygen [O(3P)] with propargyl radicals (C3H3) has first been investigated in a crossed beam configuration. The radical reactants O(3P) and C3H3 were produced by the photodissociation of NO2 and the supersonic flash pyrolysis of precursor propargyl bromide, respectively. A new exothermic channel of O(3P) + C3H3 --> C3H2 + OH was identified and the nascent distributions of the product OH in the ground vibrational state (X 2Pi:nu" = 0) showed bimodal rotational excitations composed of the low- and high-N" components without spin-orbit propensities. The averaged ratios of Pi(A')/Pi(A") were determined to be 0.60 +/- 0.28. With the aid of ab initio theory it is predicted that on the lowest doublet potential energy surface, the reaction proceeds via the addition complexes formed through the barrierless addition of O(3P) to C3H3. The common direct abstraction pathway through a collinear geometry does not occur due to the high entrance barrier in our low collision energy regime. In addition, the major reaction channel is calculated to be the formation of propynal (CHCCHO) + H, and the counterpart C3H2 of the probed OH product in the title reaction is cyclopropenylidene (1c-C3H2) after considering the factors of barrier height, reaction enthalpy and structural features of the intermediates formed along the reaction coordinate. On the basis of the statistical prior and rotational surprisal analyses, the ratio of population partitioning for the low- and high-N" is found to be about 1:2, and the reaction is described in terms of two competing addition-complex mechanisms: a major short-lived dynamic complex and a minor long-lived statistical complex. The observed unusual reaction mechanism stands in sharp contrast with the reaction of O(3P) with allyl radical (C3H5), a second significant conjugated hydrocarbon radical, which shows totally dynamic processes [J. Chem. Phys. 117, 2017 (2002)], and should be understood based upon the characteristic electronic structures and reactivity of the intermediates on the potential energy surface.
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Affiliation(s)
- Hohjai Lee
- Department of Chemistry and Center for Electro- and Photo-Responsive Molecules, Korea University, 1, Anam-dong, Seoul 136-701, Korea
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79
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Frankcombe TJ, Smith SC. Fast, scalable master equation solution algorithms. III. Direct time propagation accelerated by a diffusion approximation preconditioned iterative solver. J Chem Phys 2003. [DOI: 10.1063/1.1628213] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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80
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Howe PT, Fahr A. Pressure and Temperature Effects on Product Channels of the Propargyl (HC⋮CCH2) Combination Reaction and the Formation of the “First Ring”. J Phys Chem A 2003. [DOI: 10.1021/jp0307497] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Pui-Teng Howe
- Department of Chemistry, American University, Washington, D.C., 20016-8014
| | - Askar Fahr
- Physical and Chemical Properties Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899
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81
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Shafir EV, Slagle IR, Knyazev VD. Kinetics and Products of the Self-Reaction of Propargyl Radicals. J Phys Chem A 2003. [DOI: 10.1021/jp035648n] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Eugene V. Shafir
- Research Center for Chemical Kinetics, Department of Chemistry, The Catholic University of America, Washington, DC 20064
| | - Irene R. Slagle
- Research Center for Chemical Kinetics, Department of Chemistry, The Catholic University of America, Washington, DC 20064
| | - Vadim D. Knyazev
- Research Center for Chemical Kinetics, Department of Chemistry, The Catholic University of America, Washington, DC 20064
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82
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DeSain JD, Taatjes CA. Infrared Laser Absorption Measurements of the Kinetics of Propargyl Radical Self-Reaction and the 193 nm Photolysis of Propyne. J Phys Chem A 2003. [DOI: 10.1021/jp034047t] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- John D. DeSain
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969
| | - Craig A. Taatjes
- Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969
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83
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Giri BR, Hippler H, Olzmann M, Unterreiner AN. The rate coefficient of the C3H3 + C3H3reaction from UV absorption measurements after photolysis of dipropargyl oxalate. Phys Chem Chem Phys 2003. [DOI: 10.1039/b308518j] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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84
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Fahr A, Tardy DC. Rate Coefficients and Products of Ethyl and Vinyl Cross-Radical Reactions. J Phys Chem A 2002. [DOI: 10.1021/jp021497x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Askar Fahr
- Physical and Chemical Properties Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8381
| | - Dwight C. Tardy
- Department of Chemistry, The University of Iowa, Iowa City, Iowa 52242
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85
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Davis MJ, Klippenstein SJ. Geometric Investigation of Association/Dissociation Kinetics with an Application to the Master Equation for CH3 + CH3 ↔ C2H6. J Phys Chem A 2002. [DOI: 10.1021/jp014136a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michael J. Davis
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, and Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969
| | - Stephen J. Klippenstein
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, and Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969
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86
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Davis MJ, Kiefer JH. Modeling of nonlinear vibrational relaxation of large molecules in shock waves with a nonlinear, temperature-varying master equation. J Chem Phys 2002. [DOI: 10.1063/1.1467904] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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87
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Miller JA, Klippenstein SJ. The reaction between ethyl and molecular oxygen II: Further analysis. INT J CHEM KINET 2001. [DOI: 10.1002/kin.1063] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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