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Eraković M, Cvitaš MT. Tunneling splittings using modified WKB method in Cartesian coordinates: The test case of vinyl radical. J Chem Phys 2024; 160:154112. [PMID: 38639313 DOI: 10.1063/5.0204986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 03/31/2024] [Indexed: 04/20/2024] Open
Abstract
Modified WKB theory for calculating tunneling splittings in symmetric multi-well systems in full dimensionality is re-derived using Cartesian coordinates. It is explicitly shown that the theory rests on the wavefunction that is exact for harmonic potentials. The theory was applied to calculate tunneling splittings in vinyl radical and some of its deuterated isotopologues in their vibrational ground states and the low-lying vibrationally excited states and compared to exact variational results. The exact results are reproduced within a factor of 2 in most states. Remarkably, all large enhancements of tunneling splittings relative to the ground state, up to three orders in magnitude in some excited mode combinations, are well reproduced. It is also shown that in the asymmetrically deuterated vinyl radical, the theory correctly predicts the states that are localized in a single well and the delocalized tunneling states. Modified WKB theory on the minimum action path is computationally inexpensive and can also be applied without modification to much larger systems in full dimensionality; the results of this test case serve to give insight into the expected accuracy of the method.
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Affiliation(s)
- Mihael Eraković
- Department of Physical Chemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia
| | - Marko T Cvitaš
- Department of Physics, University of Zagreb Faculty of Science, Bijenička Cesta 32, 10000 Zagreb, Croatia
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2
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Wu Z, Wang L, Lu B, Eckhardt AK, Schreiner PR, Zeng X. Spectroscopic characterization and photochemistry of the vinylsulfinyl radical. Phys Chem Chem Phys 2021; 23:16307-16315. [PMID: 34313279 DOI: 10.1039/d1cp02584h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The simplest α,β-unsaturated sulfinyl radical CH2[double bond, length as m-dash]C(H)SO˙ has been generated in the gas phase by high-vacuum flash pyrolysis (HVFP) of sulfoxide CH2[double bond, length as m-dash]C(H)S(O)CF3 at ca. 800 °C. Two planar cis and trans conformers of CH2[double bond, length as m-dash]C(H)SO˙ were isolated in cryogenic matrixes (N2, Ne, and Ar) and characterized with IR and UV/Vis spectroscopy. In addition to the photo-induced cis ⇋ trans conformational interconversion, CH2[double bond, length as m-dash]C(H)SO˙ displays complex photochemistry. Upon irradiation with a purple light LED (400 nm), CH2[double bond, length as m-dash]C(H)SO˙ isomerizes to novel radicals CH3SCO˙, ˙CH2SC(O)H, and ˙CH2C(O)SH with concomitant dissociation to a caged molecular complex CH3S˙CO. Subsequent UV-laser (266 nm) irradiation causes fragmentation to ˙CH3/OCS and additional formation of an elusive carbonyl radical CH3C(O)S˙, which rearranges to ˙CH2C(O)SH upon further UV-light irradiation (365 nm). The vibrational data and bonding analysis of the two conformers of CH2[double bond, length as m-dash]C(H)SO˙ suggest that both are floppy radicals in which the unpaired electron conjugates with the vicinal π(C[double bond, length as m-dash]C) bond, leading to significant contribution of the canonical resonance form of ˙CH2-C(H)SO. The mechanism for the isomerization of CH2[double bond, length as m-dash]C(H)SO˙ is discussed based on the observed intermediates along with a computed potential energy profile at the CCSD(T)-F12a/aug-cc-pVTZ//B3LYP/6-311++G(3df,3pd) level of theory.
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Affiliation(s)
- Zhuang Wu
- Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysts and Innovative Materials, Fudan University, Shanghai, 200433, China.
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3
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Wang XG, Carrington T. A variational calculation of vibrational levels of vinyl radical. J Chem Phys 2020; 152:204311. [PMID: 32486683 DOI: 10.1063/5.0007225] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report the vibrational energy levels of vinyl radical (VR) that are computed with a Lanczos eigensolver and a contracted basis. Many of the levels of the two previous VR variational calculations differ significantly and differ also from those reported in this paper. We identify the source of and correct symmetry errors on the potential energy surfaces used in the previous calculations. VR has two equivalent equilibrium structures. By plotting wavefunction cuts, we show that two tunneling paths play an important role. Using the computed wavefunctions, it is possible to assign many states and thereby to determine tunneling splittings that are compared with their experimental counterparts. Our computed red shift of the hot band at 2897.23 cm-1, observed by Dong et al. [J Chem. Phys. 128, 044305 (2008)], is 4.47 cm-1, which is close to the experimental value of 4.63 cm-1.
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Affiliation(s)
- Xiao-Gang Wang
- Chemistry Department, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - Tucker Carrington
- Chemistry Department, Queen's University, Kingston, Ontario K7L 3N6, Canada
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Marks JH, Ward TB, Brathwaite AD, Duncan MA. Infrared Spectroscopy of Zn(Acetylene)n+ Complexes: Ligand Activation and Nascent Polymerization. J Phys Chem A 2020; 124:4764-4776. [DOI: 10.1021/acs.jpca.0c03358] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joshua H. Marks
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Timothy B. Ward
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | | | - Michael A. Duncan
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States
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Hayashi M, Matsubayashi H, Ichiyama T, Harada K, Tanaka K. Millimeter-wave spectroscopy of HDC=CH. J Chem Phys 2019; 151:184304. [DOI: 10.1063/1.5126671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Masato Hayashi
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Hiromu Matsubayashi
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Tomohiro Ichiyama
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Kensuke Harada
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
- International Center of Space Weather Science and Education, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
| | - Keiichi Tanaka
- Department of Chemistry, Faculty of Science, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
- International Center of Space Weather Science and Education, Kyushu University, Motooka, Nishiku, Fukuoka 819-0395, Japan
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Šmydke J, Fábri C, Sarka J, Császár AG. Rovibrational quantum dynamics of the vinyl radical and its deuterated isotopologues. Phys Chem Chem Phys 2019; 21:3453-3472. [DOI: 10.1039/c8cp04672g] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rotational–vibrational states up to 3200 cm−1, beyond the highest-lying stretching fundamental, are computed variationally for the vinyl radical (VR), H2CβCαH, and the following deuterated isotopologues of VR: CH2CD, CHDCH, and CD2CD.
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Affiliation(s)
- Jan Šmydke
- MTA-ELTE Complex Chemical Systems Research Group and Laboratory of Molecular Structure and Dynamics
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H-1117 Budapest
- Hungary
| | - Csaba Fábri
- MTA-ELTE Complex Chemical Systems Research Group and Laboratory of Molecular Structure and Dynamics
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H-1117 Budapest
- Hungary
| | - János Sarka
- Department of Chemistry and Biochemistry
- Texas Tech University
- Lubbock
- USA
| | - Attila G. Császár
- MTA-ELTE Complex Chemical Systems Research Group and Laboratory of Molecular Structure and Dynamics
- Institute of Chemistry
- ELTE Eötvös Loránd University
- H-1117 Budapest
- Hungary
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Ryazantsev SV, Tyurin DA, Feldman VI, Khriachtchev L. Spectroscopic characterization of the complex of vinyl radical and carbon dioxide: Matrix isolation and ab initio study. J Chem Phys 2017; 147:184301. [DOI: 10.1063/1.5000578] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sergey V. Ryazantsev
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
| | - Daniil A. Tyurin
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Vladimir I. Feldman
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Leonid Khriachtchev
- Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
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Yu HG, Song H, Yang M. A rigorous full-dimensional quantum dynamics study of tunneling splitting of rovibrational states of vinyl radical C2H3. J Chem Phys 2017; 146:224307. [DOI: 10.1063/1.4985183] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hua-Gen Yu
- Division of Chemistry, Department of Energy and Photon Sciences, Brookhaven National Laboratory, Upton, New York 11793-5000, USA
| | - Hongwei Song
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - Minghui Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
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Schuder MD, Wang F, Chang CH, Nesbitt DJ. Sub-Doppler infrared spectroscopy of CH 2OH radical in a slit supersonic jet: Vibration-rotation-tunneling dynamics in the symmetric CH stretch manifold. J Chem Phys 2017; 146:194307. [PMID: 28527463 DOI: 10.1063/1.4982803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The sub-Doppler CH-symmetric stretch (ν3) infrared absorption spectrum of a hydroxymethyl (CH2OH) radical is observed and analyzed with the radical formed in a slit-jet supersonic discharge expansion (Trot = 18 K) via Cl atom mediated H atom abstraction from methanol. The high sensitivity of the spectrometer and reduced spectral congestion associated with the cooled expansion enable first infrared spectroscopic observation of hydroxymethyl transitions from both ± symmetry tunneling states resulting from large amplitude COH torsional motion. Nuclear spin statistics due to exchange of the two methyl H-atoms aid in unambiguous rovibrational assignment of two A-type Ka = 0 ← 0 and Ka = 1 ← 1 bands out of each ± tunneling state, with additional spectral information obtained from spin-rotation splittings in P, Q, and R branch Ka = 1 ← 1 transitions that become resolved at low N. A high level ab initio potential surface (CCSD(T)-f12b/cc-pvnzf12 (n = 2,3)/CBS) is calculated in the large amplitude COH torsional and CH2 wag coordinates, which in the adiabatic approximation and with zero point correction predicts ground state tunneling splittings in good qualitative agreement with experiment. Of particular astrochemical interest, a combined fit of the present infrared ground state combination differences with recently reported millimeter-wave frequencies permits the determination of improved accuracy rotational constants for the ground vibrational state, which will facilitate ongoing millimeter/microwave searches for a hydroxymethyl radical in the interstellar medium.
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Affiliation(s)
- Michael D Schuder
- JILA, National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Fang Wang
- JILA, National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Chih-Hsuan Chang
- JILA, National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - David J Nesbitt
- JILA, National Institute of Standards and Technology, and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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Chang CH, Nesbitt DJ. High resolution spectroscopy of jet cooled phenyl radical: The ν1 and ν2 a1 symmetry C–H stretching modes. J Chem Phys 2016; 145:044304. [DOI: 10.1063/1.4955295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Chih-Hsuan Chang
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - David J. Nesbitt
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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11
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Chang CH, Nesbitt DJ. Sub-Doppler infrared spectroscopy of propargyl radical (H2CCCH) in a slit supersonic expansion. J Chem Phys 2015; 142:244313. [DOI: 10.1063/1.4922931] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Chih-Hsuan Chang
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309, USA
| | - David J. Nesbitt
- JILA, National Institute of Standards and Technology, University of Colorado, Boulder, Colorado 80309, USA and Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309, USA
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12
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Raston PL, Liang T, Douberly GE. Infrared spectroscopy and tunneling dynamics of the vinyl radical in 4He nanodroplets. J Chem Phys 2013; 138:174302. [DOI: 10.1063/1.4802767] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Tabor DP, Harding ME, Ichino T, Stanton JF. High-Accuracy Extrapolated Ab Initio Thermochemistry of the Vinyl, Allyl, and Vinoxy Radicals. J Phys Chem A 2012; 116:7668-76. [DOI: 10.1021/jp302527n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Daniel P. Tabor
- Institute for Theoretical Chemistry, Department of
Chemistry and Biochemistry, The University of Texas at Austin, 105 E. 24th St., A5300, Austin, Texas 78712-0165,
United States
| | - Michael E. Harding
- Institute for Theoretical Chemistry, Department of
Chemistry and Biochemistry, The University of Texas at Austin, 105 E. 24th St., A5300, Austin, Texas 78712-0165,
United States
| | - Takatoshi Ichino
- Institute for Theoretical Chemistry, Department of
Chemistry and Biochemistry, The University of Texas at Austin, 105 E. 24th St., A5300, Austin, Texas 78712-0165,
United States
| | - John F. Stanton
- Institute for Theoretical Chemistry, Department of
Chemistry and Biochemistry, The University of Texas at Austin, 105 E. 24th St., A5300, Austin, Texas 78712-0165,
United States
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Sharma AR, Bowman JM, Nesbitt DJ. Large-amplitude dynamics in vinyl radical: The role of quantum tunneling as an isomerization mechanism. J Chem Phys 2012; 136:034305. [PMID: 22280758 DOI: 10.1063/1.3666987] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Amit R Sharma
- Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA
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Jacox ME, Thompson WE. The infrared spectra of C2H4+ and C2H3 trapped in solid neon. J Chem Phys 2011; 134:064321. [DOI: 10.1063/1.3555626] [Citation(s) in RCA: 9] [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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Hayashi M, Harada K, Lavrich R, Tanaka T, Tanaka K. Millimeter-wave spectroscopy of H(2)C=CD: Tunneling splitting and ortho-para mixing interaction. J Chem Phys 2010; 133:154303. [PMID: 20969382 DOI: 10.1063/1.3478696] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The H(2)C=CD isotopic species of vinyl radical produced in a supersonic jet expansion by ultraviolet laser photolysis was studied by millimeter-wave spectroscopy. Due to the tunneling motion of the α deuteron, the ground state is split into two components, 0(+) and 0(-). Tunneling-rotation transitions connecting the lower (0(+)) and upper (0(-)) components of the tunneling doublet were observed in the frequency region of 184-334 GHz, including three R- and two Q-branch transitions. Three and two pure rotational transitions in the K(a)=0 and 1 stacks, respectively, were also observed for each of the 0(+) and 0(-) states in the frequency region of 52-159 GHz. Least-squares analysis of the observed frequencies for the tunneling-rotation and pure rotational transitions with well resolved hyperfine structures yielded a set of precise molecular constants, among which the tunneling splitting in the ground state was determined to be ΔE(0)=1187.234(17) MHz, which is 1/14 that for H(2)C=CH. The potential barrier height derived from the observed tunneling splitting by an analysis of the tunneling dynamics using a one-dimensional model is 1545 cm(-1), consistent with the value 1568 cm(-1) obtained for the normal vinyl. The observed spectrum was found to be perturbed by a hyperfine interaction connecting ortho and para levels. The constant for the interaction, which we call the ortho-para mixing Fermi contact interaction, has been determined to be δa(F) ((β))=68.06(53) MHz. This is believed to be the first definite detection of such an interaction. By this interaction the ortho and para states of H(2)C=CD are mixed up to about 0.1%. The constant is more than 1000 times larger than spin-rotation interaction constants that cause ortho-para mixing in closed shell molecules and suggests extremely rapid conversion between the ortho and para nuclear spin isomers of H(2)C=CD.
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Affiliation(s)
- Masato Hayashi
- Department of Chemistry, Faculty of Science, Kyushu University, Hakozaki, Higashiku, Fukuoka 812-8581, Japan.
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Barone V, Bloino J, Biczysko M. Validation of the DFT/N07D computational model on the magnetic, vibrational and electronic properties of vinyl radical. Phys Chem Chem Phys 2010; 12:1092-101. [DOI: 10.1039/b915246f] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Nikow M, Wilhelm MJ, Dai HL. Vibrational modes of the vinyl and deuterated vinyl radicals. J Phys Chem A 2009; 113:8857-70. [PMID: 19594157 DOI: 10.1021/jp809735e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Following the initial report of the detection of fundamental transitions of all nine vibrational modes of the vinyl radical [Letendre , L. ; Liu , D.-K. ; Pibel , C. D. ; Halpern , J. B. ; Dai , H.-L. J. Chem. Phys. 2000 , 112 , 9209] by time-resolved IR emission spectroscopy, we have re-examined the assignments of the vibrational modes through isotope substitution. Precursor molecules vinyl chloride-d3, vinyl bromide-d3, and 1,3-butadiene-d6 are used for generating vibrationally excited vinyl-d3 through 193 nm photolysis. The nondeuterated versions of these molecules along with vinyl iodide and methyl vinyl ketone are used as precursors for the production of vinyl-h3. IR emission following the 193 nm photolysis laser pulse is recorded with nanosecond time and approximately 8 cm(-1) frequency resolution. A room-temperature acetylene gas cell is used as a filter to remove the fundamental transitions of acetylene, a photolysis product, in order to reduce the complexity of the emission spectra. Two-dimensional cross-spectra correlation analysis is used to identify the emission bands from the same emitting species and improve the S/N of the emission spectra. Isotope substitution allows the identification of several low-frequency vibrational modes. For C2H3, the assigned modes are the nu4 (CC stretch) at 1595, nu5 (CH2 symmetric bend) at 1401, nu6 (CH2 asymmetric + alpha-CH bend) at 1074, nu8 (CH2 + alpha-CH symmetric out-of-plane (oop) bend) at 944, and nu9 (CH2 + alpha-CH asymmetric oop bend) at 897 cm(-1). For C2D3, the modes are the nu5 (CD2 symmetric bend) at 1060, nu6 (CD2 asymmetric + alpha-CD bend) at 820, and nu8 (CD2 + alpha-CD symmetric oop bend) at 728 cm(-1).
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Affiliation(s)
- Matthew Nikow
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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Tanaka K, Hayashi M, Ohtsuki M, Harada K, Tanaka T. Ortho-para mixing interaction in the vinyl radical detected by millimeter-wave spectroscopy. J Chem Phys 2009; 131:111101. [PMID: 19778092 DOI: 10.1063/1.3231491] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Ortho-para mixing interaction due to the coupling of nuclear and electron spins was detected for the first time by millimeter-wave spectroscopy of the deuterated vinyl radical H(2)CCD. The ground state of H(2)CCD is split by the deuteron tunneling into two components 0(+) and 0(-) separated by DeltaE(0)=1186.794(16) MHz. Rotational levels in the 0(+) and 0(-) states, one being an ortho level and the other a para level, are coupled by the interaction expressed by 0(+/-)mid R:H(')mid R:0(-/+)=(deltaa(F)/2)S(I(1)-I(2)), where I(1) and I(2) are spins of the two protons and S is the electron spin. The deltaa(F) constant has been determined to be 68.06(52) MHz. The para to ortho conversion rate constant is predicted to be 1.2x10(5) s(-1) torr(-1).
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Affiliation(s)
- Keiichi Tanaka
- Department of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki, Higashiku, Fukuoka 812-8581, Japan.
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Sharma AR, Braams BJ, Carter S, Shepler BC, Bowman JM. Full-dimensional ab initio potential energy surface and vibrational configuration interaction calculations for vinyl. J Chem Phys 2009; 130:174301. [DOI: 10.1063/1.3120607] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Reduced-Dimensional Quantum Approach to Tunneling Splittings Using Saddle-Point Normal Coordinates. J Phys Chem A 2009; 113:7556-62. [DOI: 10.1021/jp901027g] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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