1
|
Field-Theodore TE, Taylor PR. Interstellar hide and go seek: C 3H 4O. There and back (again). Phys Chem Chem Phys 2022; 24:19184-19198. [PMID: 35730752 DOI: 10.1039/d2cp00995a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular species C3H4O represents a striking example of an astrochemical conundrum. With more than 60 structural isomers theoretically possible, to date only acrolein (CH2CHCHO) has been identified in the Sgr B2(N) region of the interstellar medium (ISM). The topography of the singlet potential energy surface is complicated, with three low-lying minima predicted to be almost isoenergetic: cis and trans-acrolein, and methylketene (CH3CHCO). Our CCSD(T)/cc-pVTZ calculations confirm that methylketene is energetically lower than cis-acrolein, lying only 1.9 kJ mol-1 above the trans-isomer, which is the global minimum. In this respect, methylketene is a promising candidate for interstellar observation. Unfortunately, however, despite several searches its astronomical detection has been unsuccessful. To this end, the key question is whether in fact methylketene exists as a discrete chemical entity in the ISM at all? In this paper, we present a detailed examination of the C3H4O potential energy surface, with specific focus on formation pathways. CCSD(T)/cc-pVTZ calculations enable a more elaborate interpretation of reaction mechanisms than was published hitherto. Our results show that gauche-propargyl alcohol and syn and anti-allenol emerge as interesting new targets for observational astronomers in TMC-1: given the recent discovery of the propargyl radical in this region, barrierless product channels involving OH˙ lend support to their candidacy as possible interstellar species. Finally, this work provides accurate spectral data of these three potential molecules, to be used for searches in interstellar space.
Collapse
Affiliation(s)
| | - Peter R Taylor
- School of Pharmaceutical Science and Technology, Tianjin University, Tianjin, China.
| |
Collapse
|
2
|
Li RR, Hoffmann MR. Theoretical Calculations of the 242 nm Absorption of Propargyl Radical. J Phys Chem A 2021; 125:8595-8602. [PMID: 34570514 DOI: 10.1021/acs.jpca.1c05672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The propargyl radical, the most stable isomer of neutral C3H3, is important in combustion reactions, and a number of spectroscopic and reaction dynamics studies have been performed over the years. However, theoretical calculations have never been able to find a state that can generate strong absorption around 242 nm as seen in experiments. In this study, we calculated the low-lying electronic energy levels of the propargyl radical using the highly accurate multireference configuration interaction singles and doubles method with triples and quadruples treated perturbatively [denoted as MRCISD(TQ)]. Calculations indicate that this absorption can be attributed to a Franck-Condon-allowed electronic transition from the ground 2B1 state to the Rydberg-like excited state 12A1. Further insight into the behavior of the multireference perturbative theory methods, GVVPT2 and GVVPT3, on a very challenging system are also obtained.
Collapse
Affiliation(s)
- Run R Li
- Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202, United States
| | - Mark R Hoffmann
- Department of Chemistry, University of North Dakota, Grand Forks, North Dakota 58202, United States
| |
Collapse
|
3
|
Ashfold MNR, Ingle RA, Karsili TNV, Zhang J. Photoinduced C–H bond fission in prototypical organic molecules and radicals. Phys Chem Chem Phys 2019; 21:13880-13901. [DOI: 10.1039/c8cp07454b] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We survey and assess current knowledge regarding the primary photochemistry of hydrocarbon molecules and radicals.
Collapse
Affiliation(s)
| | | | | | - Jingsong Zhang
- Department of Chemistry
- University of California at Riverside
- Riverside
- USA
| |
Collapse
|
4
|
Broderick BM, Suas-David N, Dias N, Suits AG. Isomer-specific detection in the UV photodissociation of the propargyl radical by chirped-pulse mm-wave spectroscopy in a pulsed quasi-uniform flow. Phys Chem Chem Phys 2018; 20:5517-5529. [PMID: 29165455 DOI: 10.1039/c7cp06211g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Isomer-specific detection and product branching fractions in the UV photodissociation of the propargyl radical is achieved through the use of chirped-pulse Fourier-transform mm-wave spectroscopy in a pulsed quasi-uniform flow (CPUF). Propargyl radicals are produced in the 193 nm photodissociation of 1,2-butadiene. Absorption of a second photon leads to H atom elimination giving three possible C3H2 isomers: singlets cyclopropenylidene (c-C3H2) and propadienylidene (l-C3H2), and triplet propargylene (3HCCCH). The singlet products and their appearance kinetics in the flow are directly determined by rotational spectroscopy, but due to the negligible dipole moment of propargylene, it is not directly monitored. However, we exploit the time-dependent kinetics of H-atom catalyzed isomerization to infer the branching to propargylene as well. We obtain the overall branching among H loss channels to be 2.9% (+1.1/-0.5) l-C3H2 + H, 16.8% (+3.2/-1.3) c-C3H2 + H, and 80.2 (+1.8/-4.2) 3HCCCH + H. Our findings are qualitatively consistent with earlier RRKM calculations in that the major channel in the photodissociation of the propargyl radical at 193 nm is to 3HCCCH + H; however, a greater contribution to the energetically most favorable isomer, c-C3H2 + H is observed in this work. We do not detect the predicted HCCC + H2 channel, but place an upper bound on its yield of 1%.
Collapse
Affiliation(s)
- Bernadette M Broderick
- Department of Chemistry, University of Missouri, 601 S. College Ave, Columbia MO 65211, USA.
| | | | | | | |
Collapse
|
5
|
Garcia GA, Gans B, Krüger J, Holzmeier F, Röder A, Lopes A, Fittschen C, Alcaraz C, Loison JC. Valence shell threshold photoelectron spectroscopy of C3Hx (x = 0–3). Phys Chem Chem Phys 2018. [DOI: 10.1039/c8cp00510a] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the photoelectron spectra of C3Hx (x = 0–3) formed in a microwave discharge flow-tube reactor by consecutive H abstractions from C3H4 (C3Hx + F → C3Hx−1 + HF (x = 1–4)), but also from F + CH4 schemes by secondary reactions.
Collapse
Affiliation(s)
| | | | - Julia Krüger
- Synchrotron SOLEIL
- L'Orme des Merisiers
- Gif sur Yvette
- France
| | - Fabian Holzmeier
- Synchrotron SOLEIL
- L'Orme des Merisiers
- Gif sur Yvette
- France
- Laboratoire de Chimie Physique d'Orsay
| | - Anja Röder
- Synchrotron SOLEIL
- L'Orme des Merisiers
- Gif sur Yvette
- France
| | - Allan Lopes
- CNRS – Université Paris-Sud et Paris-Saclay
- Laboratoire de Chimie Physique
- UMR 8000
- Centre Universitaire Paris-Sud
- 91405 Orsay
| | | | - Christian Alcaraz
- CNRS – Université Paris-Sud et Paris-Saclay
- Laboratoire de Chimie Physique
- UMR 8000
- Centre Universitaire Paris-Sud
- 91405 Orsay
| | | |
Collapse
|
6
|
Loison JC, Agúndez M, Wakelam V, Roueff E, Gratier P, Marcelino N, Nuñez Reyes D, Cernicharo J, Gerin M. The interstellar chemistry of C 3H and C 3H 2 isomers. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 2017; 470:4075-4088. [PMID: 29142332 PMCID: PMC5683352 DOI: 10.1093/mnras/stx1265] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report the detection of linear and cyclic isomers of C3H and C3H2 towards various starless cores and review the corresponding chemical pathways involving neutral (C3Hx with x=1,2) and ionic (C3Hx+ with x = 1,2,3) isomers. We highlight the role of the branching ratio of electronic Dissociative Recombination (DR) reactions of C3H2+ and C3H3+ isomers showing that the statistical treatment of the relaxation of C3H* and C3H2* produced in these DR reactions may explain the relative c,l-C3H and c,l-C3H2 abundances. We have also introduced in the model the third isomer of C3H2 (HCCCH). The observed cyclic-to-linear C3H2 ratio vary from 110 ± 30 for molecular clouds with a total density around 1×104 molecules.cm-3 to 30 ± 10 for molecular clouds with a total density around 4×105 molecules.cm-3, a trend well reproduced with our updated model. The higher ratio for low molecular cloud densities is mainly determined by the importance of the H + l-C3H2 → H + c-C3H2 and H + t-C3H2 → H + c-C3H2 isomerization reactions.
Collapse
Affiliation(s)
- Jean-Christophe Loison
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, 33400, Talence, France
| | - Marcelino Agúndez
- Instituto de Ciencia de Materiales de Madrid, CSIC, C\ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - Valentine Wakelam
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - Evelyne Roueff
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, F-92190 Meudon, France
| | - Pierre Gratier
- Laboratoire d'astrophysique de Bordeaux, Univ. Bordeaux, CNRS, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
| | - Núria Marcelino
- INAF, Osservatorio di Radioastronomia, via P. Gobetti 101, 40129 Bologna, Italy
| | - Dianailys Nuñez Reyes
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, 33400, Talence, France
| | - José Cernicharo
- Instituto de Ciencia de Materiales de Madrid, CSIC, C\ Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Spain
| | - Maryvonne Gerin
- LERMA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Ecole Normale Supérieure, F-75005 Paris, France
| |
Collapse
|
7
|
Jiang X, Chen GH, Gu MQ, Wang Q, Wu D. Theoretical Study and Design of Phosphorescent Cyclometalated (C ∧C*)Pt II(acac) Complexes: The Substituent Effect Controls the Radiative and Nonradiative Decay Processes. J Phys Chem A 2017; 121:6231-6242. [PMID: 28763208 DOI: 10.1021/acs.jpca.7b04329] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Density functional theory (DFT) and time-dependent DFT calculations were performed to evaluate the influence of substituent effect of (1) R = 4-Me, (2) R = 4-OMe, and (3) R = 2,3-OC6H4 on the phenyl ring of (C∧C*)PtII(acac) (C∧C* = phenylimidazole, acac = acetylacetone), respectively, on absorption and phosphorescent spectra properties, as well as the radiative and nonradiative processes. We found that emissions of complexes 2 and 3 originate from the Kasha-like T1 state, whereas that of complex 1 originates from non-Kasha T2 state. Compared with the emission of complex 1, the emission peaks of 2 and 3 are red-shifted, which is attributed to p-π and π-π conjugation effects resulting from the electron-donating groups -OCH3 and -OC6H4 with ligand C∧C*, respectively. The radiative rate constants (κr) of 2 and 3 are larger than that of 1, namely, κr(1) < κr(2) < κr(3), indicating that κr can be efficiently increased by enlarging π-conjugation at the main ligand of (C∧C*)PtII(acac), which can cause the increase of spin-orbit coupling (SOC) matrix elements. At the same time, the activation energy barriers for the rate-limiting step can be largely raised accompanied by enlarging the ability of electron-donation of the substituent group at the main ligand of (C∧C*)PtII(acac), which can cause the decrease of the nonradiative rate constant (κnr), namely, κnr(1) > κnr(2) > κnr(3). According to ΦP = κr/(κr + κnr), the quantum yields should have the sequence ΦP(1) < ΦP(2) < ΦP(3), which is in accordance with the experiment. In addition, to guide experimental synthesis of highly efficient (C∧C*)PtII(acac), a new complex 4 through extending the π-conjugation in the C∧C* ligand of (C∧C*)PtII(acac) was theoretically designed, which has a larger quantum yield than 1-3.
Collapse
Affiliation(s)
| | | | | | - Qiang Wang
- Department of Applied Chemistry, Nanjing Tech University , Nanjing 210009, China
| | - Di Wu
- Institute of Theoretical Chemistry, Jilin University , Changchun 130023, China
| |
Collapse
|
8
|
Yang T, Dangi BB, Thomas AM, Kaiser RI. Untangling the reaction dynamics of the silylidyne radical (SiH; X2Π) with acetylene (C2H2; X1Σg+). Chem Phys Lett 2016. [DOI: 10.1016/j.cplett.2016.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
9
|
Trevitt AJ, Goulay F. Insights into gas-phase reaction mechanisms of small carbon radicals using isomer-resolved product detection. Phys Chem Chem Phys 2016; 18:5867-82. [DOI: 10.1039/c5cp06389b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Gas-phase radical reactions of CN and CH with small hydrocarbons are overviewed with emphasis on isomer-resolved product detection.
Collapse
Affiliation(s)
- Adam J. Trevitt
- School of Chemistry
- University of Wollongong
- Wollongong
- Australia
| | - Fabien Goulay
- Department of Chemistry
- West Virginia University
- Morgantown
- USA
| |
Collapse
|
10
|
Sun YL, Huang WJ, Lee SH. Formation of C3H2, C5H2, C7H2, and C9H2 from reactions of CH, C3H, C5H, and C7H radicals with C2H2. Phys Chem Chem Phys 2016; 18:2120-9. [DOI: 10.1039/c5cp06072a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A three-dimensional velocity distribution contour of C2n+1H2 produced from the reaction of C2n−1H (n = 1–4) with C2H2 in crossed molecular beams.
Collapse
Affiliation(s)
- Yi-Lun Sun
- National Synchrotron Radiation Research Center (NSRRC)
- Hsinchu 30076
- Taiwan
| | - Wen-Jian Huang
- National Synchrotron Radiation Research Center (NSRRC)
- Hsinchu 30076
- Taiwan
| | - Shih-Huang Lee
- National Synchrotron Radiation Research Center (NSRRC)
- Hsinchu 30076
- Taiwan
| |
Collapse
|
11
|
Abstract
Due to the prominent role of the propargyl radical for hydrocarbon growth within combustion environments, it is important to understand the kinetics of its formation and loss. The ab initio transition state theory-based master equation method is used to obtain theoretical kinetic predictions for the temperature and pressure dependence of the thermal decomposition of propargyl, which may be its primary loss channel under some conditions. The potential energy surface for the decomposition of propargyl is first mapped at a high level of theory with a combination of coupled cluster and multireference perturbation calculations. Variational transition state theory is then used to predict the microcanonical rate coefficients, which are subsequently implemented within the multiple-well multiple-channel master equation. A variety of energy transfer parameters are considered, and the sensitivity of the thermal rate predictions to these parameters is explored. The predictions for the thermal decomposition rate coefficient are found to be in good agreement with the limited experimental data. Modified Arrhenius representations of the rate constants are reported for utility in combustion modeling.
Collapse
Affiliation(s)
- Stephen J Klippenstein
- †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - James A Miller
- †Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Ahren W Jasper
- ‡Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551, United States
| |
Collapse
|
12
|
Osborn DL, Vogelhuber KM, Wren SW, Miller EM, Lu YJ, Case AS, Sheps L, McMahon RJ, Stanton JF, Harding LB, Ruscic B, Lineberger WC. Electronic States of the Quasilinear Molecule Propargylene (HCCCH) from Negative Ion Photoelectron Spectroscopy. J Am Chem Soc 2014; 136:10361-72. [DOI: 10.1021/ja5039984] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- David L. Osborn
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Kristen M. Vogelhuber
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Scott W. Wren
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Elisa M. Miller
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Yu-Ju Lu
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Amanda S. Case
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| | - Leonid Sheps
- Combustion Research Facility, Sandia National Laboratories, Livermore, California 94551-0969, United States
| | - Robert J. McMahon
- Department
of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706-1322, United States
| | - John F. Stanton
- Institute
for Theoretical Chemistry, Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Lawrence B. Harding
- Division
of Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Branko Ruscic
- Division
of Chemical Sciences and Engineering, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - W. Carl Lineberger
- JILA
and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0440, United States
| |
Collapse
|
13
|
Ribeiro JM, Mebel AM. Reaction Mechanism and Product Branching Ratios of the CH + C3H8 Reaction: A Theoretical Study. J Phys Chem A 2014; 118:9080-6. [DOI: 10.1021/jp502128z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joao Marcelo Ribeiro
- Department of Chemistry and
Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Alexander M. Mebel
- Department of Chemistry and
Biochemistry, Florida International University, Miami, Florida 33199, United States
| |
Collapse
|
14
|
Maity S, Parker DSN, Kaiser RI, Ganoe B, Fau S, Perera A, Bartlett RJ. Gas-Phase Synthesis of Boronylallene (H 2CCCH(BO)) under Single Collision Conditions: A Crossed Molecular Beams and Computational Study. J Phys Chem A 2014; 118:3810-3819. [PMID: 24806514 DOI: 10.1021/jp501595n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The gas phase reaction between the boron monoxide radical (11BO; X2Σ+) and allene (H2CCCH2; X1A1) was investigated experimentally under single collision conditions using the crossed molecular beam technique and theoretically exploiting ab initio electronic structure and statistical (RRKM) calculations. The reaction was found to follow indirect (complex forming) scattering dynamics and proceeded via the formation of a van der Waals complex (11BOC3H4). This complex isomerized via addition of the boron monoxide radical (11BO; X2Σ+) with the radical center located at the boron atom to the terminal carbon atom of the allene molecule forming a H2CCCH211BO intermediate on the doublet surface. The chemically activated H2CCCH211BO intermediate underwent unimolecular decomposition via atomic hydrogen elimination from the terminal carbon atom holding the boronyl group through a tight exit transition state to synthesize the boronylallene product (H2CCCH11BO) in a slightly exoergic reaction (55 ± 11 kJ mol-1). Statistical (RRKM) calculations suggest that minor reaction channels lead to the products 3-propynyloxoborane (CH2(11BO)CCH) and 1-propynyloxoborane (CH3CC11BO) with fractions of 1.5% and 0.2%, respectively. The title reaction was also compared with the cyano (CN; X2Σ+)-allene and boronyl-methylacetylene reactions to probe similarities, but also differences of these isoelectronic systems. Our investigation presents a novel gas phase synthesis and characterization of a hitherto elusive organyloxoborane (RBO) monomer-boronylallene-which is inherently tricky to isolate in the condensed phase except in matrix studies; our work further demonstrates that the crossed molecular beams approach presents a useful tool in investigating the chemistry and synthesis of highly reactive organyloxoboranes.
Collapse
Affiliation(s)
- Surajit Maity
- Department of Chemistry, University of Hawaii at Manoa , Honolulu, Hawaii 96822, United States
| | - Dorian S N Parker
- Department of Chemistry, University of Hawaii at Manoa , Honolulu, Hawaii 96822, United States
| | - Ralf I Kaiser
- Department of Chemistry, University of Hawaii at Manoa , Honolulu, Hawaii 96822, United States
| | - Brad Ganoe
- Quantum Theory Project, University of Florida , Gainesville, Florida 32611, United States
| | - Stefan Fau
- Quantum Theory Project, University of Florida , Gainesville, Florida 32611, United States
| | - Ajith Perera
- Quantum Theory Project, University of Florida , Gainesville, Florida 32611, United States
| | - Rodney J Bartlett
- Quantum Theory Project, University of Florida , Gainesville, Florida 32611, United States
| |
Collapse
|
15
|
Maity S, Parker DSN, Dangi BB, Kaiser RI, Fau S, Perera A, Bartlett RJ. A crossed molecular beam and ab-initio investigation of the reaction of boron monoxide (BO; X2Σ+) with methylacetylene (CH3CCH; X1A1): competing atomic hydrogen and methyl loss pathways. J Phys Chem A 2013; 117:11794-807. [PMID: 23651442 DOI: 10.1021/jp402743y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The gas-phase reaction of boron monoxide ((11)BO; X(2)Σ(+)) with methylacetylene (CH3CCH; X(1)A1) was investigated experimentally using crossed molecular beam technique at a collision energy of 22.7 kJ mol(-1) and theoretically using state of the art electronic structure calculation, for the first time. The scattering dynamics were found to be indirect (complex forming reaction) and the reaction proceeded through the barrier-less formation of a van-der-Waals complex ((11)BOC3H4) followed by isomerization via the addition of (11)BO(X(2)Σ(+)) to the C1 and/or C2 carbon atom of methylacetylene through submerged barriers. The resulting (11)BOC3H4 doublet radical intermediates underwent unimolecular decomposition involving three competing reaction mechanisms via two distinct atomic hydrogen losses and a methyl group elimination. Utilizing partially deuterated methylacetylene reactants (CD3CCH; CH3CCD), we revealed that the initial addition of (11)BO(X(2)Σ(+)) to the C1 carbon atom of methylacetylene was followed by hydrogen loss from the acetylenic carbon atom (C1) and from the methyl group (C3) leading to 1-propynyl boron monoxide (CH3CC(11)BO) and propadienyl boron monoxide (CH2CCH(11)BO), respectively. Addition of (11)BO(X(2)Σ(+)) to the C1 of methylacetylene followed by the migration of the boronyl group to the C2 carbon atom and/or an initial addition of (11)BO(X(2)Σ(+)) to the sterically less accessible C2 carbon atom of methylacetylene was followed by loss of a methyl group leading to the ethynyl boron monoxide product (HCC(11)BO) in an overall exoergic reaction (78 ± 23 kJ mol(-1)). The branching ratios of these channels forming CH2CCH(11)BO, CH3CC(11)BO, and HCC(11)BO were derived to be 4 ± 3%, 40 ± 5%, and 56 ± 15%, respectively; these data are in excellent agreement with the calculated branching ratios using statistical RRKM theory yielding 1%, 38%, and 61%, respectively.
Collapse
Affiliation(s)
- Surajit Maity
- Department of Chemistry, University of Hawai'i at Manoa , Honolulu, Hawaii 96822, United States
| | | | | | | | | | | | | |
Collapse
|
16
|
Lockyear JF, Welz O, Savee JD, Goulay F, Trevitt AJ, Taatjes CA, Osborn DL, Leone SR. Isomer Specific Product Detection in the Reaction of CH with Acrolein. J Phys Chem A 2013; 117:11013-26. [DOI: 10.1021/jp407428v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Jessica F. Lockyear
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Oliver Welz
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California, 94551, United States
| | - John D. Savee
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California, 94551, United States
| | - Fabien Goulay
- Department
of Chemistry, West Virginia University, Morgantown, West Virginia, 26506, United States
| | - Adam J. Trevitt
- School
of Chemistry, University of Wollongong, Wollongong, NSW 2522 Australia
| | - Craig A. Taatjes
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California, 94551, United States
| | - David L. Osborn
- Combustion
Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California, 94551, United States
| | - Stephen R. Leone
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
- Departments
of Chemistry and Physics, University of California, Berkeley, California 94720, United States
| |
Collapse
|
17
|
Wilson AV, Parker DSN, Zhang F, Kaiser RI. Crossed beam study of the atom-radical reaction of ground state carbon atoms (C(3P)) with the vinyl radical (C2H3(X2A')). Phys Chem Chem Phys 2012; 14:477-81. [PMID: 22120638 DOI: 10.1039/c1cp22993a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The atom-radical reaction of ground state carbon atoms (C((3)P)) with the vinyl radical (C(2)H(3)(X(2)A')) was conducted under single collision conditions at a collision energy of 32.3 ± 2.9 kJ mol(-1). The reaction dynamics were found to involve a complex forming reaction mechanism, which is initiated by the barrier-less addition of atomic carbon to the carbon-carbon-double bond of the vinyl radical forming a cyclic C(3)H(3) radical intermediate. The latter has a lifetime of at least 1.5 times its rotational period and decomposes via a tight exit transition state located about 45 kJ mol(-1) above the separated products through atomic hydrogen loss to the cyclopropenylidene isomer (c-C(3)H(2)) as detected toward cold molecular clouds and in star forming regions.
Collapse
Affiliation(s)
- Antony V Wilson
- Department of Chemistry, University of Hawai'i at Manoa, Honolulu, HI 96822, USA
| | | | | | | |
Collapse
|
18
|
Kaiser RI, Gu X, Zhang F, Maksyutenko P. Crossed beam reactions of methylidyne [CH(X2Π)] with D2-acetylene [C2D2(X1Σg+)] and of D1-methylidyne [CD(X2Π)] with acetylene [C2H2(X1Σg+)]. Phys Chem Chem Phys 2012; 14:575-88. [DOI: 10.1039/c1cp22635e] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
19
|
Maksyutenko P, Zhang F, Gu X, Kaiser RI. A crossed molecular beam study on the reaction of methylidyne radicals [CH(X2Π)] with acetylene [C2H2(X1Σg+)]—competing C3H2+ H and C3H + H2channels. Phys Chem Chem Phys 2011; 13:240-52. [DOI: 10.1039/c0cp01529f] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
20
|
Li Y, Liu HL, Zhou ZJ, Huang XR, Sun CC. Reaction Mechanism of CH + C3H6: A Theoretical Study. J Phys Chem A 2010; 114:9496-506. [DOI: 10.1021/jp102029w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan Li
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People’s Republic of China
| | - Hui-ling Liu
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People’s Republic of China
| | - Zhong-Jun Zhou
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People’s Republic of China
| | - Xu-ri Huang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People’s Republic of China
| | - Chia-chung Sun
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People’s Republic of China
| |
Collapse
|
21
|
Castiglioni L, Vukovic S, Crider PE, Lester WA, Neumark DM. Intramolecular competition in the photodissociation of C3D3 radicals at 248 and 193 nm. Phys Chem Chem Phys 2010; 12:10714-22. [DOI: 10.1039/c0cp00380h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
22
|
Leonori F, Petrucci R, Balucani N, Hickson KM, Hamberg M, Geppert WD, Casavecchia P, Rosi M. Crossed-beam and theoretical studies of the S(1D) + C2H2 reaction. J Phys Chem A 2009; 113:4330-9. [PMID: 19260670 DOI: 10.1021/jp810989p] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction dynamics of excited sulfur atoms, S((1)D), with acetylene has been investigated by the crossed-beam scattering technique with mass spectrometric detection and time-of-flight (TOF) analysis at the collision energy of 35.6 kJ mol(-1). These studies have been made possible by the development of intense continuous supersonic beams of S((3)P,(1)D) atoms. From product angular and TOF distributions, center-of-mass product angular and translational energy distributions are derived. The S((1)D) + C(2)H(2) reaction is found to lead to formation of HCCS (thioketenyl) + H, while the only other energetically allowed channels, those leading to CCS((3)Sigma(-), (1)Delta) + H(2), are not observed to occur to an appreciable extent. The dynamics of the H-elimination channel is discussed and elucidated. The interpretation of the scattering results is assisted by synergic high-level ab initio electronic structure calculations of stationary points and product energetics for the C(2)H(2)S ground-state singlet potential energy surface. In addition, by exploiting the novel capability of performing product detection by means of a tunable electron-impact ionizer, we have obtained the first experimental information on the ionization energy of thioketenyl radical, HCCS, as synthesized in the reactive scattering experiment. This has been complemented by ab initio calculations of the adiabatic and vertical ionization energies for the ground-state radical. The theoretically derived value of 9.1 eV confirms very recent, accurate calculations and is corroborated by the experimentally determined ionization threshold of 8.9 +/- 0.3 eV for the internally warm HCCS produced from the title reaction.
Collapse
Affiliation(s)
- Francesca Leonori
- Dipartimento di Chimica, Universita degli Studi di Perugia, 06123 Perugia, Italy
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Zheng X, Song Y, Zhang J. Ultraviolet Photodissociation Dynamics of the Propargyl Radical. J Phys Chem A 2009; 113:4604-12. [DOI: 10.1021/jp8113336] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xianfeng Zheng
- Department of Chemistry, University of California at Riverside, Riverside, California 92521
| | - Yu Song
- Department of Chemistry, University of California at Riverside, Riverside, California 92521
| | - Jingsong Zhang
- Department of Chemistry, University of California at Riverside, Riverside, California 92521
| |
Collapse
|
24
|
Crider PE, Castiglioni L, Kautzman KE, Neumark DM. Photodissociation of the propargyl and propynyl (C3D3) radicals at 248 and 193 nm. J Chem Phys 2009; 130:044310. [DOI: 10.1063/1.3067705] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
25
|
Goulay F, Trevitt AJ, Meloni G, Selby TM, Osborn DL, Taatjes CA, Vereecken L, Leone SR. Cyclic Versus Linear Isomers Produced by Reaction of the Methylidyne Radical (CH) with Small Unsaturated Hydrocarbons. J Am Chem Soc 2009; 131:993-1005. [DOI: 10.1021/ja804200v] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fabien Goulay
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Adam J. Trevitt
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Giovanni Meloni
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Talitha M. Selby
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - David L. Osborn
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Craig A. Taatjes
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Luc Vereecken
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| | - Stephen R. Leone
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, California 94720, Departments of Chemistry and Physics, University of California, Berkeley, California 94720, Combustion Research Facility, Mail Stop 9055, Sandia National Laboratories, Livermore, California 94551-0969, and Department of Chemistry, K. U. Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
| |
Collapse
|
26
|
Loison JC, Bergeat A. Rate constants and the H atom branching ratio of the reactions of the methylidyne CH(X2Π) radical with C2H2, C2H4, C3H4(methylacetylene and allene), C3H6(propene) and C4H8(trans-butene). Phys Chem Chem Phys 2009; 11:655-64. [DOI: 10.1039/b812810c] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
27
|
Poully B, Bergeat A, Hannachi Y. Theoretical Study of the Mechanism and Rate Constant of the B + CO2 Reaction. J Phys Chem A 2008; 112:8148-53. [DOI: 10.1021/jp804504g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Benjamin Poully
- ISM Groupe de Spectroscopie Moléculaire and ISM Groupe d’Astrochimie, Université Bordeaux, Institut des Sciences Moléculaires (UMR 5255 CNRS), 351, cours de la Libération, F-33405 Talence cedex, France, and CNRS UMR 5255, ISM, Talence, France
| | - Astrid Bergeat
- ISM Groupe de Spectroscopie Moléculaire and ISM Groupe d’Astrochimie, Université Bordeaux, Institut des Sciences Moléculaires (UMR 5255 CNRS), 351, cours de la Libération, F-33405 Talence cedex, France, and CNRS UMR 5255, ISM, Talence, France
| | - Yacine Hannachi
- ISM Groupe de Spectroscopie Moléculaire and ISM Groupe d’Astrochimie, Université Bordeaux, Institut des Sciences Moléculaires (UMR 5255 CNRS), 351, cours de la Libération, F-33405 Talence cedex, France, and CNRS UMR 5255, ISM, Talence, France
| |
Collapse
|
28
|
Goncher SJ, Moore DT, Sveum NE, Neumark DM. Photofragment translational spectroscopy of propargyl radicals at 248nm. J Chem Phys 2008; 128:114303. [DOI: 10.1063/1.2840350] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
29
|
Zhang F, Gu X, Guo Y, Kaiser RI. Reaction Dynamics of Phenyl Radicals (C6H5) with Propylene (CH3CHCH2) and Its Deuterated Isotopologues. J Phys Chem A 2008; 112:3284-90. [DOI: 10.1021/jp711146a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Fangtong Zhang
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - Xibin Gu
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - Ying Guo
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| | - Ralf I. Kaiser
- Department of Chemistry, University of Hawaii at Manoa, Honolulu, Hawaii 96822
| |
Collapse
|
30
|
Woon DE. Quantum Chemical Evaluation of the Astrochemical Significance of Reactions between S Atom and Acetylene or Ethylene. J Phys Chem A 2007; 111:11249-53. [PMID: 17536790 DOI: 10.1021/jp0708392] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Addition-elimination reactions of S atom in its 3P ground state with acetylene (C2H2) and ethylene (C2H4) were characterized with both molecular orbital and density functional theory calculations employing correlation consistent basis sets in order to assess the likelihood that either reaction might play a general role in astrochemistry or a specific role in the formation of S2 (X3Sigmag-) via a mechanism proposed by Saxena, P. P.; Misra, A. Mon. Not. R. Astron. Soc. 1995, 272, 89. The acetylene and ethylene reactions proceed through C2H2S (3A' ') and C2H4S (3A' ') intermediates, respectively, to yield HCCS (2Pi) and C2H3S (2A'). Substantial barriers were found in the exit channels for every combination of method and basis set considered in this work, which effectively precludes hydrogen elimination pathways for both S + C2H2 and S + C2H4 in the ultracold interstellar medium where only very modest barriers can be surmounted and processes without barriers tend to predominate. However, if one or both intermediates are formed and stabilized efficiently under cometary or dense interstellar cloud conditions, they could serve as temporary reservoirs for the S atom and participate in reactions such as S + C2H2S --> S2 + C2H2 or S + C2H4S --> S2 + C2H4. For formation and stabilization to be efficient, the reaction must possess a barrier height small enough to be surmountable at low temperatures yet large enough to prevent redissociation to reactants. Barrier heights computed with B3LYP and large basis sets are very low, but more rigorous QCISD(T) and RCCSD(T) results indicate that the barrier heights are closer to 3-4 kcal/mol. The calculations therefore indicate that S + C2H2 or S + C2H4 could contribute to the formation of S2 in comets and may serve as a means to gauge coma temperature. The energetics of the ethylene reaction are more favorable.
Collapse
Affiliation(s)
- David E Woon
- Molecular Research Institute, 1000 Elwell Court, Suite 105, Palo Alto, California 94303, USA.
| |
Collapse
|
31
|
McCunn LR, FitzPatrick BL, Krisch MJ, Butler LJ, Liang CW, Lin JJ. Unimolecular dissociation of the propargyl radical intermediate of the CH+C2H2 and C+C2H3 reactions. J Chem Phys 2006; 125:133306. [PMID: 17029459 DOI: 10.1063/1.2353821] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
This paper examines the unimolecular dissociation of propargyl (HCCCH2) radicals over a range of internal energies to probe the CH+HCCH and C+C2H3 bimolecular reactions from the radical intermediate to products. The propargyl radical was produced by 157 nm photolysis of propargyl chloride in crossed laser-molecular beam scattering experiments. The H-loss and H2 elimination channels of the nascent propargyl radicals were observed. Detection of stable propargyl radicals gave an experimental determination of 71.5 (+5-10) kcal/mol as the lowest barrier to dissociation of the radical. This barrier is significantly lower than predictions for the lowest barrier to the radical's dissociation and also lower than calculated overall reaction enthalpies. Products from both H2+HCCC and H+C3H2 channels were detected at energies lower than what has been theoretically predicted. An HCl elimination channel and a minor C-H fission channel were also observed in the photolysis of propargyl chloride.
Collapse
Affiliation(s)
- Laura R McCunn
- The James Franck Institute and Department of Chemistry, University of Chicago, Chicago, Illinois 60637, USA
| | | | | | | | | | | |
Collapse
|
32
|
Smith IWM, Sage AM, Donahue NM, Herbst E, Quan D. The temperature-dependence of rapid low temperature reactions: experiment, understanding and prediction. Faraday Discuss 2006; 133:137-56; discussion 191-230, 449-52. [PMID: 17191447 DOI: 10.1039/b600721j] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Despite the success of the CRESU (Cinétique de Réaction en Ecoulement Supersonique Uniforme) method in measuring rate coefficients for neutral-neutral reactions of radicals down close to the very low temperatures prevalent in dense interstellar clouds (ISCs), there are still many reactions of potential importance in the chemistry of these objects for which there have been no measurements of low temperature rate coefficients. One important class of reactions is that between atomic and molecular free radicals and unsaturated hydrocarbons; that is, alkynes and alkenes. Based on semi-empirical arguments and correlations of 'room temperature' rate coefficients, k(298 K), for reactions of this type with the difference between the ionisation energy of the alkyne/alkene and the electron affinity of the radical, we suggest which reactions between the radicals, C(3P), O(3P), N(4S), CH, C2H and CN, and carbon chain molecules (Cn) and cyanopolyynes (HC2nCN and NCC2nCN) are likely to be fast at the temperature of dense ISCs. These reactions and rate coefficients have been incorporated into a purely gas-phase model (osu2005) of ISC chemistry. The results of these calculations are presented and discussed.
Collapse
Affiliation(s)
- Ian W M Smith
- University Chemical Laboratories, Lensfield Road, Cambridge, UK.
| | | | | | | | | |
Collapse
|
33
|
Mebel AM, Kislov VV, Kaiser RI. Potential Energy Surface and Product Branching Ratios for the Reaction of Dicarbon, C2(XΣg+), with Methylacetylene, CH3CCH(X1A1): An Ab Initio/RRKM Study. J Phys Chem A 2005; 110:2421-33. [PMID: 16480301 DOI: 10.1021/jp054309m] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Ab initio calculations of the potential energy surface for the C(2)(X(1)Sigma(g)(+)) + CH(3)CCH(X(1)A(1)) reaction have been carried at the G2M level of theory. The calculations show that the dicarbon molecule in the ground singlet electronic state can add to methylacetylene without a barrier producing a three-member or a four-member ring intermediate, which can rapidly rearrange to the most stable H(3)CCCCCH isomer on the C(5)H(4) singlet surface. This isomer can then lose a hydrogen atom (H) or molecular hydrogen (H(2)) from the CH(3) group with the formation of H(2)CCCCCH and HCCCCCH, respectively. Alternatively, H atom migrations and three-member-ring closure/opening rearrangements followed by H and H(2) losses can lead to other isomers of the C(5)H(3) and C(5)H(2) species. According to the calculated energetics, the C(2)(X(1)Sigma(g)(+)) + CH(3)CCH reaction is likely to be a major source of the C(5)H(3) radicals (in particular, the most stable H(2)CCCCCH and HCCCHCCH isomers, which are relevant to the formation of benzene through the reactions with CH(3)). Among heavy-fragment product channels, only C(3)H(3) + C(2)H and c-C(3)H(2) + C(2)H(2) might compete with C(5)H(3) + H and C(5)H(2) + H(2). RRKM calculations of reaction rate constants and product branching ratios depending on the reactive collision energy showed that the major reaction products are expected to be H(2)CCCCCH + H (64-66%) and HCCCHCCH + H (34-30%), with minor contributions from HCCCCCH + H(2) (1-2%), HCCCHCC + H(2) (up to 1%), C(3)H(3) + C(2)H (up to 1%), and c-C(3)H(2) + C(2)H(2) (up to 0.1%) if the energy randomization is complete. The calculations also indicate that the C(2)(X(1)Sigma(g)(+)) + CH(3)CCH(X(1)A(1)) reaction can proceed by direct H-abstraction of a methyl hydrogen to form C(3)H(3) + C(2)H almost without a barrier.
Collapse
Affiliation(s)
- A M Mebel
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, USA
| | | | | |
Collapse
|
34
|
Daugey N, Caubet P, Retail B, Costes M, Bergeat A, Dorthe G. Kinetic measurements on methylidyne radical reactions with several hydrocarbons at low temperatures. Phys Chem Chem Phys 2005; 7:2921-7. [PMID: 16189612 DOI: 10.1039/b506096f] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The temperature dependences of the methylidyne radical reactions with methane, allene, methylacetylene and propene were studied. This work was carried out in a supersonic flow reactor coupled with pulsed laser photolysis (PLP) and laser-induced fluorescence (LIF) techniques. Three Laval nozzles were designed to provide uniform supersonic expansions of nitrogen at Mach 2 and of argon at Mach 2 and 3 to reach low temperatures, e.g. 170, 128 and 77 K, respectively. CH radicals were produced by PLP of CHBr3 at 266 nm and probed by LIF. The exponential decays of the CH fluorescence were acquired, hydrocarbons being introduced in excess. The rate constants for the CH+CH4 reaction are in good agreement with the temperature dependence proposed by Canosa et al. (A. Canosa, I. R. Sims, D. Travers, I. W. M. Smith and B. R. Rowe, Astron. Astrophys., 1997, 323, 644-651, ) i.e. 3.96x10(-8)(T/K)(-1.04) exp(-36.1 K/T) in the range 23-298 K. The rate constants of the CH+C3H4(allene), CH+C3H4(methylacetylene) and CH+C3H6(propene) reactions exhibit a small temperature dependence between 77 and 170 K, with a maximum rate around 100 K close to (4.3-4.6)x10(-10) cm3 molecule-1 s-1.
Collapse
Affiliation(s)
- Nicolas Daugey
- Laboratoire de Physico-Chimie Moléculaire, CNRS UMR5803, Université Bordeaux 1, F-33405, Talence Cedex, France
| | | | | | | | | | | |
Collapse
|
35
|
Sun YC, Wang IT, Nguyen TL, Lu HF, Yang X, Mebel AM. A Combined Quantum Chemistry and RRKM Calculation Predicts the O(1D) + C2H6 Reaction Can Produce Water Molecule in a Collision-Free Crossed Molecular Beam Environment. J Phys Chem A 2003. [DOI: 10.1021/jp027439t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ying-Chieh Sun
- Department of Chemistry, National Taiwan Normal University, 88 Tingchow Road Sec. 4, Taipei 11718, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, Republic of China, and Chemistry Department, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - I-Ting Wang
- Department of Chemistry, National Taiwan Normal University, 88 Tingchow Road Sec. 4, Taipei 11718, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, Republic of China, and Chemistry Department, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Thanh Lam Nguyen
- Department of Chemistry, National Taiwan Normal University, 88 Tingchow Road Sec. 4, Taipei 11718, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, Republic of China, and Chemistry Department, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Hsiu-Feng Lu
- Department of Chemistry, National Taiwan Normal University, 88 Tingchow Road Sec. 4, Taipei 11718, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, Republic of China, and Chemistry Department, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Xueming Yang
- Department of Chemistry, National Taiwan Normal University, 88 Tingchow Road Sec. 4, Taipei 11718, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, Republic of China, and Chemistry Department, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - Alexander M. Mebel
- Department of Chemistry, National Taiwan Normal University, 88 Tingchow Road Sec. 4, Taipei 11718, Taiwan, Republic of China, Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan, Republic of China, and Chemistry Department, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| |
Collapse
|
36
|
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
| |
Collapse
|
37
|
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
| |
Collapse
|