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Gore JPP, Mahoney EJD, Smith JA, Ashfold MNR, Mankelevich YA. Imaging and Modeling C 2 Radical Emissions from Microwave Plasma-Activated Methane/Hydrogen Gas Mixtures: Contributions from Chemiluminescent Reactions and Investigations of Higher-Pressure Effects and Plasma Constriction. J Phys Chem A 2021; 125:4184-4199. [PMID: 33966382 DOI: 10.1021/acs.jpca.1c01924] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Wavelength and spatially resolved imaging and 2D plasma chemical modeling methods have been used to study the emission from electronically excited C2 radicals in microwave-activated dilute methane/hydrogen gas mixtures under processing conditions relevant to the chemical vapor deposition (CVD) of diamond. Obvious differences in the spatial distributions of the much-studied C2(d3Πg-a3Πu) Swan band emission and the little-studied, higher-energy C2(C1Πg-A1Πu) emission are rationalized by invoking a chemiluminescent (CL) reactive source, most probably involving collisions between H atoms and C2H radicals, that acts in tandem with the widely recognized electron impact excitation source term. The CL source is relatively much more important for forming C2(d) state radicals and is deduced to account for >40% of C2(d) production in the hot plasma core under base operating conditions, which should encourage caution when estimating electron or gas temperatures from C2 Swan band emission measurements. Studies at higher pressures (p ≈ 400 Torr) offer new insights into the plasma constriction that hampers efforts to achieve higher diamond CVD rates by using higher processing pressures. Plasma constriction is proposed as being inevitable in regions where the local electron density (ne) exceeds some critical value (nec) and electron-electron collisions enhance the rates of H2 dissociation, H-atom excitation, and related associative ionization processes relative to those prevailing in the neighboring nonconstricted plasma region. The 2D modeling identifies a further challenge to high-p operation. The radial uniformities of the CH3 radical and H-atom concentrations above the growing diamond surface both decline with increasing p, which are likely to manifest as less spatially uniform diamond growth (in terms of both rate and quality).
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Affiliation(s)
- Joseph P P Gore
- School of Chemistry, University of Bristol, Bristol, U.K. BS8 1TS
| | - Edward J D Mahoney
- School of Chemistry, University of Bristol, Bristol, U.K. BS8 1TS.,Centre for Doctoral Training in Diamond Science and Technology, University of Warwick, Gibbet Hill Road, Coventry, U.K. CV4 7AL
| | - James A Smith
- School of Chemistry, University of Bristol, Bristol, U.K. BS8 1TS
| | | | - Yuri A Mankelevich
- Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia
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2
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Jiang J, Du Z, Liévin J, Field RW. One-colour (∼220 nm) resonance-enhanced (S 1 − S 0) multi-photon dissociation of acetylene: probe of the C 2 A1 Π u − X1 Σ +g band by frequency-modulation spectroscopy. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1724340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Jun Jiang
- Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA, USA
| | - Zhenhui Du
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, People's Republic of China
| | - Jacques Liévin
- Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
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3
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Jiang J, Du Z, Field RW. Determination of the sign of the population difference in a two-level system by frequency-modulation spectroscopy. Mol Phys 2020. [DOI: 10.1080/00268976.2019.1660007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Jun Jiang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Zhenhui Du
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin, People's Republic of China
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA
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4
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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.
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Affiliation(s)
| | | | | | - Jingsong Zhang
- Department of Chemistry
- University of California at Riverside
- Riverside
- USA
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5
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Aguirre NF, Díaz-Tendero S, Hervieux PA, Alcamí M, Martín F. M 3C: A Computational Approach To Describe Statistical Fragmentation of Excited Molecules and Clusters. J Chem Theory Comput 2017; 13:992-1009. [PMID: 28005371 DOI: 10.1021/acs.jctc.6b00984] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Microcanonical Metropolis Monte Carlo method, based on a random sampling of the density of states, is revisited for the study of molecular fragmentation in the gas phase (isolated molecules, atomic and molecular clusters, complex biomolecules, etc.). A random walk or uniform random sampling in the configurational space (atomic positions) and a uniform random sampling of the relative orientation, vibrational energy, and chemical composition of the fragments is used to estimate the density of states of the system, which is continuously updated as the random sampling populates individual states. The validity and usefulness of the method is demonstrated by applying it to evaluate the caloric curve of a weakly bound rare gas cluster (Ar13), to interpret the fragmentation of highly excited small neutral and singly positively charged carbon clusters (Cn, n = 5,7,9 and Cn+, n = 4,5) and to simulate the mass spectrum of the acetylene molecule (C2H2).
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Affiliation(s)
- Néstor F Aguirre
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid , 28049 Madrid, Spain
| | - Sergio Díaz-Tendero
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid , 28049 Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , 28049 Madrid, Spain
| | - Paul-Antoine Hervieux
- Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg , 67000 Strasbourg, France
| | - Manuel Alcamí
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid , 28049 Madrid, Spain.,Instituto Madrileño de Estudios Avanzados en Nanociencias (IMDEA-Nanociencia) , 28049 Madrid, Spain
| | - Fernando Martín
- Departamento de Química, Módulo 13, Universidad Autónoma de Madrid , 28049 Madrid, Spain.,Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid , 28049 Madrid, Spain.,Instituto Madrileño de Estudios Avanzados en Nanociencias (IMDEA-Nanociencia) , 28049 Madrid, Spain
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6
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Limbu TB, Quintero KJP, Hidalgo A, Makarov VI, Huang D, Morell G, Weiner BR. Observation of the C 2 H radical using (1 + 2) REMPI via theB̃2A′←X̃2Σ+transition. Chem Phys 2016. [DOI: 10.1016/j.chemphys.2016.09.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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7
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Morgan WJ, Fortenberry RC. Theoretical Rovibronic Treatment of the X̃ 2Σ+ and à 2Π States of C2H and the X̃ 1Σ+ State of C2H– from Quartic Force Fields. J Phys Chem A 2015; 119:7013-25. [DOI: 10.1021/acs.jpca.5b03489] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- W. James Morgan
- Department of Chemistry, Georgia Southern University, Statesboro, Georgia 30460, United States
| | - Ryan C. Fortenberry
- Department of Chemistry, Georgia Southern University, Statesboro, Georgia 30460, United States
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8
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Najar F, Ben Abdallah D, Jaidane N. Potential energy surfaces for the C2 (X1Σg+,a3Πu)+H (2S) system. Application: Rotational dynamics of C2 (X1Σg+) on the ground adiabatic and diabatic 2A′ surfaces. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.05.052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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9
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Canneaux S, Wallet A, Ribaucour M, Louis F. A theoretical study of the NCN (3Σ−) biradical thermochemical properties: Implications for combustion chemistry. COMPUT THEOR CHEM 2011. [DOI: 10.1016/j.comptc.2011.03.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Zhang Y, Yuan K, Yu S, Parker DH, Yang X. Photodissociation dynamics of acetylene via the C̃ Π1u electronic state. J Chem Phys 2010; 133:014307. [DOI: 10.1063/1.3456738] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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11
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Fortenberry RC, King RA, Stanton JF, Crawford TD. A benchmark study of the vertical electronic spectra of the linear chain radicals C2H and C4H. J Chem Phys 2010; 132:144303. [DOI: 10.1063/1.3376073] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
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12
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Joseph S, Varandas AJC. Ab initio Based DMBE Potential Energy Surface for the Ground Electronic State of the C2H Molecule. J Phys Chem A 2010; 114:2655-64. [DOI: 10.1021/jp910269w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Joseph
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
| | - A. J. C. Varandas
- Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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14
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van Hemert M, van Dishoeck E. Photodissociation of small carbonaceous molecules of astrophysical interest. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2007.08.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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15
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Apaydin G, Fink WH, Jackson WM. Photodissociation of CCH: Classical trajectory calculations involving seven electronic states. J Chem Phys 2004; 121:9368-77. [PMID: 15538856 DOI: 10.1063/1.1793912] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The photodissociation dynamics of ethynyl radical, C(2)H, involving seven electronic states is studied by classical trajectory calculations. Initial values of the trajectories are selected based on relative absorption intensities calculated by Mebel et al. The energies and the derivatives are interpolated by three-dimensional cubic spline interpolator using an extended data pool. Mean square errors and standard deviations in interpolation of energies for 450 data points are found to be in the range 3.1 x 10(-6)-1.4 x 10(-5) and 1.7 x 10(-3)-3.8 x 10(-3) hartrees, respectively. The photofragments of C(2) and H are produced mainly in the X (1)Sigma(g) (+), a (3)Pi(u), b (3)Sigma(g) (-), c (3)Sigma(u) (+), A (1)Pi(u), B (1)Delta(g) electronic states of C(2) as product. The avoided crossings do not appear to be in the main dissociation pathways. The internal distributions are in good accord with the experimental results where comparison is possible, suggesting that the fragmentation mechanism of C(2)H(2) into C(2) and H is a two step process involving C(2)H radical as an intermediate with a life time long enough to allow complete collection of the phase space in the experiments.
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Affiliation(s)
- Gökşin Apaydin
- Department of Chemistry, University of California, Davis, California 95616, USA
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16
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Sumiyoshi Y, Ueno T, Endo Y. Characterization of the CCCl radical in the X̃ 2A′ state by Fourier-transform microwave spectroscopy and ab initio calculations. J Chem Phys 2003. [DOI: 10.1063/1.1581851] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
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17
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Baer M, Mebel AM, Billing GD. Necessary Conditions for a Rigorous Minimal Diabatic Potential Matrix. J Phys Chem A 2002. [DOI: 10.1021/jp020105j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Michael Baer
- Department of Chemistry, H.C. Ørsted Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark, Department of Physics and Applied Mathematics, Soreq NRC, Yavne 81800, Israel, and Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10764, Taiwan
| | - Alexander M. Mebel
- Department of Chemistry, H.C. Ørsted Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark, Department of Physics and Applied Mathematics, Soreq NRC, Yavne 81800, Israel, and Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10764, Taiwan
| | - Gert D. Billing
- Department of Chemistry, H.C. Ørsted Institute, University of Copenhagen, 2100 Copenhagen Ø, Denmark, Department of Physics and Applied Mathematics, Soreq NRC, Yavne 81800, Israel, and Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10764, Taiwan
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18
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Affiliation(s)
- H Sato
- Laser Photochemistry Research Group, Department of Chemistry for Materials, Faculty of Engineering, Mi'e University, 1515 Kamihamacho, Tsu 514-8507, Japan.
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Mebel AM, Yahalom A, Englman R, Baer M. The study of conical intersections between consecutive pairs of the five lowest 2A′ states of the C2H molecule. J Chem Phys 2001. [DOI: 10.1063/1.1389842] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Pak C, Wesolowski SS, Rienstra-Kiracofe JC, Yamaguchi Y, Schaefer HF. What is the true electronic ground state of the disilaethynyl radical (SiSiH): 2B1 or 2A1? J Chem Phys 2001. [DOI: 10.1063/1.1384418] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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21
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Mebel AM, Hayashi M, Jackson WM, Wrobel J, Green M, Xu D, Lin SH. Branching ratios of C2 products in the photodissociation of C2H at 193 nm. J Chem Phys 2001. [DOI: 10.1063/1.1370942] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Mebel AM, Baer M, Lin SH. Degenerate conical intersections: The interaction between the 3 2A′ and 4 2A′ electronic states of C2H as a case study. J Chem Phys 2001. [DOI: 10.1063/1.1356004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Mebel AM, Baer M, Rozenbaum VM, Lin SH. Ab initio study of nonadiabatic coupling matrix elements between excited 22A′ and 32A′ electronic states of C2H. Chem Phys Lett 2001. [DOI: 10.1016/s0009-2614(01)00110-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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24
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Mebel AM, Baer M, Lin SH. Probing the nature of surface intersection by ab initio calculations of the nonadiabatic coupling matrix elements: A conical intersection due to bending motion in C2H. J Chem Phys 2000. [DOI: 10.1063/1.481712] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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25
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Chiang WY, Hsu YC. Fluorescence lifetimes and predissociation processes in the B̃ 2A′ state of CCH. J Chem Phys 2000. [DOI: 10.1063/1.481339] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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26
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Affiliation(s)
- Whe-Yi Chiang
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 107, Taiwan, Republic of China
| | - Yen-Chu Hsu
- Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 107, Taiwan, Republic of China
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