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Sivaramakrishnan R, Michael JV, Harding LB, Klippenstein SJ. Shock tube explorations of roaming radical mechanisms: the decompositions of isobutane and neopentane. J Phys Chem A 2012; 116:5981-9. [PMID: 22394380 DOI: 10.1021/jp210959j] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The thermal decompositions of isobutane and neopentane have been studied using both shock tube experiments and ab initio transition state theory based master equation calculations. Dissociation rate constants for these molecules have been measured at high temperatures (1260-1566 K) behind reflected shock waves using high-sensitivity H-ARAS detection. The two major dissociation channels at high temperature are iso-C(4)H(10) → CH(3) + i-C(3)H(7) (1a) and neo-C(5)H(12) → CH(3) + t-C(4)H(9) (2a). Ultrahigh-sensitivity ARAS detection of H-atoms produced from the rapid decomposition of the product radicals, i-C(3)H(7) in (1a) and t-C(4)H(9) in (2a), through i-C(3)H(7) + M → H + C(3)H(6) + M (3a) and t-C(4)H(9) + M → H + i-C(4)H(8) + M (4a) allowed measurements of both the total decomposition rate constants, k(total), and the branching to radical products, which were observed to be equivalent in both systems, k(1a)/k(total) and k(2a)/k(total) = 0.79 ± 0.05. Theoretical analyses indicate that in isobutane, the non-H-atom fraction has two contributions, the dominant fraction being due to the roaming radical mechanism leading to molecular products through iso-C(4)H(10) → CH(4) + C(3)H(6) (1b) with k(1b)/k(total) = 0.16, and a minor fraction that involves the isomerization of i-C(3)H(7) to n-C(3)H(7) that then subsequently forms methyl radicals, i-C(3)H(7) + M → n-C(3)H(7) + M → CH(3) + C(2)H(4) + M (3b). In contrast to isobutane, in neopentane, the contribution to the non-H-atom fraction is exclusively through the roaming radical mechanism that leads to neo-C(5)H(12) → CH(4) + i-C(4)H(8) (2b) with k(2b)/k(total) = 0.21. These quantitative measurements of larger contributions from the roaming mechanism for larger molecules are in agreement with the qualitative theoretical arguments that suggest long-range dispersion interactions (which become increasingly important for larger molecules) may enhance roaming.
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Affiliation(s)
- R Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Sivaramakrishnan R, Su MC, Michael JV, Klippenstein SJ, Harding LB, Ruscic B. Shock Tube and Theoretical Studies on the Thermal Decomposition of Propane: Evidence for a Roaming Radical Channel. J Phys Chem A 2011; 115:3366-79. [DOI: 10.1021/jp2006205] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- R. Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - M.-C. Su
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - J. V. Michael
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - S. J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - L. B. Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - B. Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
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Sivaramakrishnan R, Su MC, Michael JV, Klippenstein SJ, Harding LB, Ruscic B. Rate Constants for the Thermal Decomposition of Ethanol and Its Bimolecular Reactions with OH and D: Reflected Shock Tube and Theoretical Studies. J Phys Chem A 2010; 114:9425-39. [DOI: 10.1021/jp104759d] [Citation(s) in RCA: 126] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - M.-C. Su
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - J. V. Michael
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - S. J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - L. B. Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - B. Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
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Kiefer JH, Gupte KS, Harding LB, Klippenstein SJ. Shock tube and theory investigation of cyclohexane and 1-hexene decomposition. J Phys Chem A 2010; 113:13570-83. [PMID: 19842681 DOI: 10.1021/jp905891q] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The decomposition of cyclohexane (c-C(6)H(12)) was studied in a shock tube using the laser-schlieren technique over the temperature range 1300-2000 K and for 25-200 Torr in mixtures of 2%, 4%, 10%, and 20% cyclohexane in Kr. Vibrational relaxation of the cyclohexane was also examined in 10 experiments covering 1100-1600 K for pressures below 20 Torr, and relaxation was found to be too fast to allow resolution of incubation times. The dissociation of 1-hexene (1- C(6)H(12)), apparently the sole initial product of cyclohexane decomposition, was also studied over 1220-1700 K for 50 and 200 Torr using 2% and 3% 1-hexene in Kr. On heating, cyclohexane simply isomerizes to 1-hexene, and this then dissociates almost entirely by a more rapid C-C scission to allyl and n-propyl radicals. This two-step reaction results in an initial small density gradient from the slight endothermicity of the isomerization. The gradient then rises strongly as the product 1-hexene dissociates. For the lower temperatures, this behavior is fully resolved here. For the higher pressures, 1-hexene decomposition generates negative gradients (exothermic reaction) as the radicals formed begin to recombine. Cyclohexane also generates such gradients, but these are now much smaller because the radical pool is depleted by abstraction from the reactant. A complete mechanism for the 1-hexene decomposition and for that of cyclohexane involving 79 reactions and 30 species is used in the final modeling of the gradients. Rate constants and RRKM fit parameters for the initial reactions are provided for the entire range of conditions. The possibility of direct reaction to allyl and n-propyl radicals, without stabilization of the intermediate 1-hexene, is examined down to pressures as low as 25 Torr, without a clear resolution of the issue. High-pressure limit rate constants from RRKM extrapolation are k(infinity)(c-C(6)H(12) --> 1-C(6)H(12)) = (8.76 x 10(17)) exp((-91.94 kcal/mol)/RT) s(-1) (T = 1300-2000 K) and k(infinity)(1-C(6)H(12) --> (*)C(3)H(7) + (*)C(3)H(5)) = (1.46 x 10(16)) exp((-69.12 kcal/mol)/RT) s(-1) (T = 1200-1700 K). This high-pressure rate for cyclohexane is entirely consistent with the notion that the isomerization involves initial C-C fission to a diradical. These extrapolated high-pressure rates are in good agreement with much of the literature.
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Affiliation(s)
- J H Kiefer
- Department of Chemical Engineering, University of Illinois at Chicago, Chicago, Illinois 60607, USA.
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Klippenstein SJ, Harding LB, Ruscic B, Sivaramakrishnan R, Srinivasan NK, Su MC, Michael JV. Thermal Decomposition of NH2OH and Subsequent Reactions: Ab Initio Transition State Theory and Reflected Shock Tube Experiments. J Phys Chem A 2009; 113:10241-59. [PMID: 19722533 DOI: 10.1021/jp905454k] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- S. J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - L. B. Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B. Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - R. Sivaramakrishnan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - N. K. Srinivasan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M.-C. Su
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - J. V. Michael
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Gannon KL, Blitz MA, Pilling MJ, Seakins PW, Klippenstein SJ, Harding LB. Kinetics and product branching ratios of the reaction of (1)CH2 with H2 and D2. J Phys Chem A 2008; 112:9575-83. [PMID: 18714945 DOI: 10.1021/jp803038s] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reactions of singlet methylene (a(1)A1 (1)CH2) with hydrogen and deuterium have been studied by experimental and theoretical techniques. The rate coefficients for the removal of singlet methylene with H2 (k1) and D2 (k2) have been measured from 195 to 798 K and are essentially temperature-independent with values of k1 = (10.48 +/- 0.32) x 10(-11) cm(3) molecule(-1) s(-1) and k2 = (5.98 +/- 0.34) x 10(-11) cm(3) molecule(-1) s(-1), where the errors represent 2sigma, giving a ratio of k1/k2 = 1.75 +/- 0.11. In the reaction with H2, singlet methylene can be removed by reaction giving CH3 + H or deactivated to ground-state triplet methylene. Direct measurement of the H atom product showed that the fraction of relaxation decreased from 0.3 at 195 K to essentially zero at 398 K. For the reaction with deuterium, either H or D may be eliminated. Experimentally, the H:D ratio was determined to be 1.8 +/- 0.5 over the range 195-398 K. Theoretically, the reaction kinetics has been predicted with variable reaction coordinate transition state theory and with rigid-body trajectory simulations employing various high-level, ab initio-determined potential energy surfaces. The magnitudes of the calculated rate coefficients are in agreement with experiment, but the calculations show a significant negative temperature dependence that is not observed in the experimental results. The calculated and experimental H to D ratios from the reaction of singlet methylene with D2 are in good agreement, suggesting that the reaction proceeds entirely through the formation of a long-lived methane intermediate with a statistical distribution of energy.
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Affiliation(s)
- K L Gannon
- School of Chemistry, University of Leeds, Leeds, LS2 9JT, United Kingdom
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Srinivasan NK, Su MC, Michael JV, Jasper AW, Klippenstein SJ, Harding LB. Thermal Decomposition of CF3 and the Reaction of CF2 + OH → CF2O + H. J Phys Chem A 2007; 112:31-7. [DOI: 10.1021/jp076344u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- N. K. Srinivasan
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - M.-C. Su
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - J. V. Michael
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - A. W. Jasper
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - S. J. Klippenstein
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - L. B. Harding
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439
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Srinivasan NK, Su MC, Michael JV, Klippenstein SJ, Harding LB. Reflected Shock Tube and Theoretical Studies of High-Temperature Rate Constants for OH + CF3H ⇆ CF3 + H2O and CF3 + OH → Products. J Phys Chem A 2007; 111:6822-31. [PMID: 17503789 DOI: 10.1021/jp0706228] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reflected shock tube technique with multipass absorption spectrometric detection of OH radicals at 308 nm, using either 36 or 60 optical passes corresponding to total path lengths of 3.25 or 5.25 m, respectively, has been used to study the bimolecular reactions, OH+CF3H-->CF3+H2O (1) and CF3+H2O-->OH+CF3H (-1), between 995 and 1663 K. During the course of the study, estimates of rate constants for CF3+OH-->products (2) could also be determined. Experiments on reaction -1 were transformed through equilibrium constants to k1, giving the Arrhenius expression k1=(9.7+/-2.1)x10(-12) exp(-4398+/-275K/T) cm3 molecule(-1) s(-1). Over the temperature range, 1318-1663 K, the results for reaction 2 were constant at k2=(1.5+/-0.4)x10(-11) cm3 molecule(-1) s(-1). Reactions 1 and -1 were also studied with variational transition state theory (VTST) employing QCISD(T) properties for the transition state. These a priori VTST predictions were in good agreement with the present experimental results but were too low at the lower temperatures of earlier experiments, suggesting that either the barrier height was overestimated by about 1.3 kcal/mol or that the effect of tunneling was greatly underestimated. The present experimental results have been combined with the most accurate earlier studies to derive an evaluation over the extended temperature range of 252-1663 K. The three parameter expression k1=2.08x10(-17) T1.5513 exp(-1848 K/T) cm3 molecule(-1) s(-1) describes the rate behavior over this temperature range. Alternatively, the expression k1,th=1.78x10(-23) T3.406 exp(-837 K/T) cm3 molecule(-1) s(-1) obtained from empirically adjusted VTST calculations over the 250-2250 K range agrees with the experimental evaluation to within a factor of 1.6. Reaction 2 was also studied with direct CASPT2 variable reaction coordinate transition state theory. The resulting predictions for the capture rate are found to be in good agreement with the mean of the experimental results and can be represented by the expression k2,th=2.42x10(-11) T-0.0650 exp(134 K/T) cm3 molecule(-1) s(-1) over the 200-2500 K temperature range. The products of this reaction are predicted to be CF2O+HF.
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Affiliation(s)
- N K Srinivasan
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Townsend D, Lahankar SA, Lee SK, Chambreau SD, Suits AG, Zhang X, Rheinecker J, Harding LB, Bowman JM. The Roaming Atom: Straying from the Reaction Path in Formaldehyde Decomposition. Science 2004; 306:1158-61. [PMID: 15498970 DOI: 10.1126/science.1104386] [Citation(s) in RCA: 432] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We present a combined experimental and theoretical investigation of formaldehyde (H2CO) dissociation to H2 and CO at energies just above the threshold for competing H elimination. High-resolution state-resolved imaging measurements of the CO velocity distributions reveal two dissociation pathways. The first proceeds through a well-established transition state to produce rotationally excited CO and vibrationally cold H2. The second dissociation pathway yields rotationally cold CO in conjunction with highly vibrationally excited H2. Quasi-classical trajectory calculations performed on a global potential energy surface for H2CO suggest that this second channel represents an intramolecular hydrogen abstraction mechanism: One hydrogen atom explores large regions of the potential energy surface before bonding with the second H atom, bypassing the saddle point entirely.
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Affiliation(s)
- D Townsend
- Department of Chemistry, Stony Brook University, Stony Brook, NY 11794, USA
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Michael JV, Su MC, Sutherland JW, Harding LB, Wagner AF. Rate Constants for D + C2H2 → C2HD + H at High Temperature: Implications to the High Pressure Rate Constant for H + C2H2 → C2H3. J Phys Chem A 2003. [DOI: 10.1021/jp035170n] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- J. V. Michael
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - M.-C. Su
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - J. W. Sutherland
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - L. B. Harding
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - A. F. Wagner
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
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Fang DC, Harding LB, Klippenstein SJ, Miller JA. A direct transition state theory based analysis of the branching in NH2 + NO. Faraday Discuss 2002:207-22; discussion 255-74. [PMID: 11877992 DOI: 10.1039/b102235k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A combination of high-level quantum-chemical simulations and sophisticated transition state theory analyses is employed in a study of the temperature dependence of the N2H + OH-->HNNOH recombination reaction. The implications for the branching between N2H + OH and N2 + H2O in the NH2 + NO reaction are also explored. The transition state partition function for the N2H + OH recombination reaction is evaluated with a direct implementation of variable reaction coordinate (VRC) transition state theory (TST). The orientation dependent interaction energies are directly determined at the CAS + 1 + 2/cc-pvdz level. Corrections for basis set limitations are obtained via calculations along the cis and trans minimum energy paths employing an approximately aug-pvtz basis set. The calculated rate constant for the N2H + OH-->HNNOH recombination is found to decrease significantly with increasing temperature, in agreement with the predictions of our earlier theoretical study. Conventional transition state theory analyses, employing new coupled cluster estimates for the vibrational frequencies and energies at the saddlepoints along the NH2 + NO reaction pathway, are coupled with the VRC-TST analyses for the N2H + OH channels to provide estimates for the branching in the NH2 + NO reaction. Modest variations in the exothermicity of the reaction (1-2 kcal mol-1), and in a few of the saddlepoint energies (2-4 kcal mol-1), yield TST based predictions for the branching fraction that are in satisfactory agreement with related experimental results. The unmodified results are in reasonable agreement for higher temperatures, but predict too low a branching ratio near room temperature, as well as too steep an initial rise.
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Affiliation(s)
- D C Fang
- Chemistry Division, Argonne National Laboratory, Argonne, IL 60439, USA
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Su MC, Kumaran SS, Lim KP, Michael JV, Wagner AF, Harding LB, Fang DC. Rate Constants, 1100 ≤ T ≤ 2000 K, for H + NO2 → OH + NO Using Two Shock Tube Techniques: Comparison of Theory to Experiment. J Phys Chem A 2002. [DOI: 10.1021/jp0141023] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- M.-C. Su
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - S. S. Kumaran
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - K. P. Lim
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - J. V. Michael
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - A. F. Wagner
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - L. B. Harding
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - D.-C. Fang
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
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Lester MI, Pond BV, Marshall MD, Anderson DT, Harding LB, Wagner AF. Mapping the OH + CO-->HOCO reaction pathway through IR spectroscopy of the OH-CO reactant complex. Faraday Discuss 2002:373-85; discussion 419-31. [PMID: 11605276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
A hydrogen-bonded complex composed of the OH and CO reactants has been identified along the OH + CO-->HOCO reaction pathway. IR action spectroscopy in the OH overtone region has been used to examine the vibrational modes of the linear OH-CO complex, including intermolecular bending modes that probe portions of the reaction path leading to HOCO. The spectroscopic measurements have accessed highly excited intermolecular levels, with energies up to 250 cm-1 above the zero-point level, which lie in close proximity to the transition state for reaction. The OH-CO binding energy, D0 < or = 430 cm-1, has also been established from the quantum state distribution of the OH fragments following vibrational predissociation of the OH-CO complex. Complementary electronic structure calculations have been performed to characterize the OH-CO and OH-OC complexes, the transition state for HOCO formation, and the direct reaction path that connects the experimentally observed OH-CO complex to the HOCO intermediate.
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Affiliation(s)
- M I Lester
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA.
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Harding LB, Troe J, Ushakov VG. Comment on “On the high pressure rate constants for the H/Mu + O2 addition reactions’' by J. M. C. Marques and A. J. C. Varandas, Phys. Chem. Chem. Phys., 2001, 3, 505. Phys Chem Chem Phys 2001. [DOI: 10.1039/b102050l] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Harding LB, Maergoiz AI, Troe J, Ushakov VG. Statistical rate theory for the HO+O⇔HO2⇔H+O2 reaction system: SACM/CT calculations between 0 and 5000 K. J Chem Phys 2000. [DOI: 10.1063/1.1314374] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wu GS, Schatz GC, Lendvay G, Fang DC, Harding LB. Erratum: “A new potential surface and quasiclassical trajectory study of H+H2O→OH+H2” [J. Chem. Phys. 113, 3150 (2000)]. J Chem Phys 2000. [DOI: 10.1063/1.1311968] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Wu GS, Schatz GC, Lendvay G, Fang DC, Harding LB. A new potential surface and quasiclassical trajectory study of H+H2O→OH+H2. J Chem Phys 2000. [DOI: 10.1063/1.1287329] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Harding LB, Troe J, Ushakov VG. Classical trajectory calculations of the high pressure limiting rate constants and of specific rate constants for the reaction H+O2→HO2: dynamic isotope effects between tritium+O2 and muonium+O2. Phys Chem Chem Phys 2000. [DOI: 10.1039/a908929b] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Alagia M, Balucani N, Cartechini L, Casavecchia P, Volpi GG, Pederson LA, Schatz GC, Lendvay G, Harding LB, Hollebeek T, Ho TS, Rabitz H. Exploring the reaction dynamics of nitrogen atoms: A combined crossed beam and theoretical study of N(2D)+D2→ND+D. J Chem Phys 1999. [DOI: 10.1063/1.478806] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Schatz GC, Wu G, Lendvay G, Fang DC, Harding LB. Reaction of H with highly vibrationally excited water: activated or not? Faraday Discuss 1999. [DOI: 10.1039/a901950b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Kumaran SS, Su MC, Lim KP, Michael JV, Wagner AF, Harding LB, Dixon DA. Ab Initio Calculations and Three Different Applications of Unimolecular Rate Theory for the Dissociations of CCl4, CFCl3, CF2Cl2, and CF3Cl. ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp9600470] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. S. Kumaran
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - M.-C. Su
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - K. P. Lim
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - J. V. Michael
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - A. F. Wagner
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - L. B. Harding
- Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439
| | - D. A. Dixon
- DuPont Central Research and Development Experimental Station, Wilmington, Delaware 19880-0328
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Ma Z, Liu K, Harding LB, Komotos M, Schatz GC. Differential cross sections for fine structure transitions in O(3P2)+Ar collisions. J Chem Phys 1994. [DOI: 10.1063/1.466796] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Computational studies of basic chemical processes not only provide numbers for comparison with experiment or for use in modeling complex chemical phenomena such as combustion, but also provide insight into the fundamental factors that govern molecular structure and change which cannot be obtained from experiment alone. We summarize the results of three case studies, on HCO, OH + H(2), and O + C(2)H(2), which illustrate the range of problems that can be addressed by using modern theoretical techniques. In all cases, the potential energy surfaces were characterized by using ab initio electronic structure methods. Collisions between molecules leading to reaction or energy transer were described with quantum dynamical methods (HCO), classical trajectory techniques (HCO and OH + H(2)), and statistical methods (HCO, OH + H(2), and O + C(2)H(2)). We can anticipate dramatic increases in the scope of this work as new generations of computers are introduced and as new chemistry software is developed to exploit these computers.
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