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Karaev E, Gerlach M, Theil K, Garcia GA, Alcaraz C, Loison JC, Fischer I. Photoelectron spectrum of the pyridyl radical. Phys Chem Chem Phys 2024; 26:17042-17047. [PMID: 38836386 DOI: 10.1039/d4cp00688g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
We report the photoelectron spectrum of the pyridyl radical (C5H4N), a species of interest in astrochemistry and combustion. The radicals were produced via hydrogen abstraction in a fluorine discharge and ionized with synchrotron radiation. Mass-selected slow photoelectron spectra of the products were obtained from photoelectron-photoion coincidence spectra. A Franck-Condon simulation based on computed geometries and vibrational frequencies identified contributions of the o- and p-pyridyl radicals. For the o-isomer an adiabatic ionisation energy of 7.70 eV was obtained, in excellent agreement with a computed value of 7.72 eV. The spectrum of o-pyridyl is characterized by a long progression in an in-plane bending mode and the N-C stretch that contains the radical site.
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Affiliation(s)
- Emil Karaev
- University of Würzburg, Institute of Physical and Theoretical Chemistry, Am Hubland, 97074 Würzburg, Germany.
| | - Marius Gerlach
- University of Würzburg, Institute of Physical and Theoretical Chemistry, Am Hubland, 97074 Würzburg, Germany.
| | - Katharina Theil
- University of Würzburg, Institute of Physical and Theoretical Chemistry, Am Hubland, 97074 Würzburg, Germany.
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St Aubin, B.P. 48, F-91192 Gif sur Yvette, France
| | - Christian Alcaraz
- Universite Paris-Saclay, CNRS, Institut de Chimie Physique, UMR8000, 91405 Orsay, France
| | | | - Ingo Fischer
- University of Würzburg, Institute of Physical and Theoretical Chemistry, Am Hubland, 97074 Würzburg, Germany.
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2
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Lin SY, Chou SL, Tseng CM, Wu YJ. IR absorption spectra of aniline cation, anilino radical, and phenylnitrene isolated in solid argon. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2022; 276:121233. [PMID: 35405375 DOI: 10.1016/j.saa.2022.121233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/29/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
Electron bombardment of aniline (PhNH2) in an Ar matrix mainly generated the aniline cation (PhNH2+), anilino (PhNH) and phenyl (Ph) radicals, and phenylnitrene (PhN). Further irradiation of the electron-bombarded matrix sample at 365 nm depleted PhNH2+ and PhN, and resulted in the formation of PhNH2, PhNH, and Ph. In separate experiments, irradiation of the PhNH2/Ar matrix samples at 265 or 160 nm mainly generated PhNH and Ph radicals, but without the formation of PhNH2+ and PhN. According to the observed photochemical behaviors, quantum-chemically predicted harmonic vibrational wavenumbers of each species, and the information reported in previous photodissociation studies, we unambiguously characterized the IR features of the aromatic species. The information of the vibrational fundamentals of PhNH is new and the formation mechanism is discussed.
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Affiliation(s)
- Shu-Yu Lin
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
| | - Sheng-Lung Chou
- National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan
| | - Chien-Ming Tseng
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan
| | - Yu-Jong Wu
- Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan; National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan.
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3
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Chicharro DV, Hrodmarsson HR, Bouallagui A, Zanchet A, Loison JC, García GA, García-Vela A, Bañares L, Marggi Poullain S. Threshold Photoelectron Spectroscopy of the CH 2I, CHI, and CI Radicals. J Phys Chem A 2021; 125:6122-6130. [PMID: 34232644 PMCID: PMC8478278 DOI: 10.1021/acs.jpca.1c03874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
VUV photoionization of the CHnI radicals (with n = 0, 1, and 2) is investigated by means of synchrotron radiation coupled with a double imaging photoion-photoelectron coincidence spectrometer. Photoionization efficiencies and threshold photoelectron spectra (TPES) for photon energies ranging between 9.2 and 12.0 eV are reported. An adiabatic ionization energy (AIE) of 8.334 ± 0.005 eV is obtained for CH2I, which is in good agreement with previous results [8.333 ± 0.015 eV, Sztáray J. Chem. Phys. 2017, 147, 013944], while for CI an AIE of 8.374 ± 0.005 eV is measured for the first time and a value of ∼8.8 eV is estimated for CHI. Ab initio calculations have been carried out for the ground state of the CH2I radical and for the ground state and excited states of the radical cation CH2I+, including potential energy curves along the C-I coordinate. Franck-Condon factors are calculated for transitions from the CH2I(X̃2B1) ground state of the neutral radical to the ground state and excited states of the radical cation. The TPES measured for the CH2I radical shows several structures that correspond to the photoionization into excited states of the radical cation and are fully assigned on the basis of the calculations. The TPES obtained for the CHI is characterized by a broad structure peaking at 9.335 eV, which could be due to the photoionization from both the singlet and the triplet states and into one or more electronic states of the cation. A vibrational progression is clearly observed in the TPES for the CI radical and a frequency for the C-I stretching mode of 760 ± 60 cm-1 characterizing the CI+ electronic ground state has been extracted.
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Affiliation(s)
- David V Chicharro
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Helgi Rafn Hrodmarsson
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
| | - Aymen Bouallagui
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, C/Serrano, 123, 28006 Madrid, Spain.,Laboratoire de Spectroscopie Atomique, Moléculaire et Applications-LSAMA LR01ES09, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis, Tunisia
| | - Alexandre Zanchet
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, C/Serrano, 123, 28006 Madrid, Spain
| | - Jean-Christophe Loison
- ISM, Université Bordeaux 1, CNRS, 351 cours de la Libération, 33405 Talence Cedex, France
| | - Gustavo A García
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
| | - Alberto García-Vela
- Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, C/Serrano, 123, 28006 Madrid, Spain
| | - Luis Bañares
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.,Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanoscience), Cantoblanco, 28049 Madrid, Spain
| | - Sonia Marggi Poullain
- Departamento de Química Física (Unidad Asociada I+D+i al CSIC), Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain
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4
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Johansen SL, Xu Z, Westerfield JH, Wannenmacher AC, Crabtree KN. Coupled Cluster Characterization of 1-, 2-, and 3-Pyrrolyl: Parameters for Vibrational and Rotational Spectroscopy. J Phys Chem A 2021; 125:1257-1268. [PMID: 33502858 DOI: 10.1021/acs.jpca.0c09833] [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
Pyrrolyl (C4H4N) is a nitrogen-containing aromatic radical that is a derivative of pyrrole (C4H5N) and is an important intermediate in the combustion of biomass. It is also relevant for chemistry in Titan's atmosphere and may be present in the interstellar medium. The lowest-energy isomer, 1-pyrrolyl, has been involved in many experimental and theoretical studies of the N-H photodissociation of pyrrole, yet it has only been directly spectroscopically detected via electron paramagnetic resonance and through the photoelectron spectrum of the pyrrolide anion, yielding three vibrational frequencies. No direct measurements of 2- or 3-pyrrolyl have been made, and little information is known from theoretical calculations beyond their relative energies. Here, we present an ab initio quantum chemical characterization of the three pyrrolyl isomers at the CCSD(T) level of theory in their ground electronic states, with an emphasis on spectroscopic parameters relevant for vibrational and rotational spectroscopy. Equilibrium geometries were optimized at the CCSD(T)/cc-pwCVTZ level of theory, and the quadratic, cubic, and partial quartic force constants were evaluated at CCSD(T)/ANO0 for analysis using second-order vibrational perturbation theory to obtain harmonic and anharmonic vibrational frequencies. In addition, zero-point-corrected rotational constants, electronic spin-rotation tensors, and nuclear hyperfine tensors are calculated for rotational spectroscopy. Our computed structures and energies agree well with earlier density functional theory calculations, and spectroscopic parameters for 1-pyrrolyl are compared with the limited existing experimental data. Finally, we discuss strategies for detecting these radicals using rotational and vibrational spectroscopy on the basis of the calculated spectroscopic constants.
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Affiliation(s)
- Sommer L Johansen
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Zhongxing Xu
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - J H Westerfield
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Anna C Wannenmacher
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
| | - Kyle N Crabtree
- Department of Chemistry, University of California, Davis, One Shields Avenue, Davis, California 95616, United States
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5
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Derbali I, Hrodmarsson HR, Schwell M, Bénilan Y, Poisson L, Hochlaf M, Alikhani ME, Guillemin JC, Zins EL. Unimolecular decomposition of methyl ketene and its dimer in the gas phase: theory and experiment. Phys Chem Chem Phys 2020; 22:20394-20408. [PMID: 32914152 DOI: 10.1039/d0cp03921g] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a combined theoretical and experimental investigation on the single photoionization and dissociative photoionization of gas-phase methyl ketene (MKE) and its neutral dimer (MKE2). The performed experiments entail the recording of photoelectron photoion coincidence (PEPICO) spectra and slow photoelectron spectra (SPES) in the energy regime 8.7-15.5 eV using linearly polarized synchrotron radiation. We observe both dimerization and trimerization of the monomer which brings about significantly complex and abstruse dissociative ionization patterns. These require the implementation of theoretical calculations to explore the potential energy surfaces of the monomer and dimer's neutral and ionized geometries. To this end, explicitly correlated quantum chemical methodologies involving the coupled cluster with single, double and perturbative triple excitations (R)CCSD(T)-F12 method, are utilized. An improvement in the adiabatic ionization energy of MKE is presented (AIE = 8.937 ± 0.020 eV) as well as appearance energies for multiple fragments formed through dissociative ionization of either the MKE monomer or dimer. In this regard, the synergy of experiment and theory is crucial to interpreting the obtained results. We discuss the potential astrochemical implications of this work in the context of recent advances in the field of astrochemistry and speculate on the potential presence and eventual fate of interstellar MKE molecules.
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Affiliation(s)
- Imene Derbali
- MONARIS UMR 8233 CNRS, Sorbonne Université, 4 Place Jussieu, 75252 Paris Cedex 5, France
| | - Helgi Rafn Hrodmarsson
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, BP 48, Gif sur Yvette, France and Laboratory for Astrophysics, Leiden Observatory, Leiden University, PO Box 9513, NL-2300 RA Leiden, The Netherlands.
| | - Martin Schwell
- LISA UMR 7583 Université Paris-Est Créteil and Université de Paris, Institut Pierre et Simon Laplace, 61 Avenue du Général de Gaulle, 94010 Créteil, France
| | - Yves Bénilan
- LISA UMR 7583 Université Paris-Est Créteil and Université de Paris, Institut Pierre et Simon Laplace, 61 Avenue du Général de Gaulle, 94010 Créteil, France
| | - Lionel Poisson
- Université Paris-Saclay, CEA, CNRS, LIDYL, 91191 Gif-sur-Yvette, France
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs sur Marne, France.
| | | | - Jean-Claude Guillemin
- Univ Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, ISCR-UMR6226, F-35000 Rennes, France
| | - Emilie-Laure Zins
- MONARIS UMR 8233 CNRS, Sorbonne Université, 4 Place Jussieu, 75252 Paris Cedex 5, France
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6
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Hemberger P, Pan Z, Bodi A, Bokhoven JA, Ormond TK, Ellison GB, Genossar N, Baraban JH. The Threshold Photoelectron Spectrum of Fulvenone: A Reactive Ketene Derivative in Lignin Valorization. Chemphyschem 2020; 21:2217-2222. [DOI: 10.1002/cphc.202000477] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/29/2020] [Indexed: 11/07/2022]
Affiliation(s)
- Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry Paul Scherrer Institute CH-5232 Villigen PSI Switzerland
| | - Zeyou Pan
- Laboratory for Synchrotron Radiation and Femtochemistry Paul Scherrer Institute CH-5232 Villigen PSI Switzerland
- Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Zurich Switzerland
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry Paul Scherrer Institute CH-5232 Villigen PSI Switzerland
| | - Jeroen A. Bokhoven
- Institute for Chemical and Bioengineering Department of Chemistry and Applied Biosciences ETH Zurich Zurich Switzerland
- Laboratory for Catalysis and Sustainable Chemistry Paul Scherrer Institute CH-5232 Villigen PSI Switzerland
| | - Thomas K. Ormond
- Department of Chemistry and Biochemistry University of Colorado Boulder Colorado 80309-0215 United States
| | - G. Barney Ellison
- Department of Chemistry and Biochemistry University of Colorado Boulder Colorado 80309-0215 United States
| | - Nadav Genossar
- Department of Chemistry Ben Gurion University of the Negev Beer Sheva 84105 Israel
- Israel Atomic Energy Commission Tel Aviv 61070 Israel
| | - Joshua H. Baraban
- Department of Chemistry Ben Gurion University of the Negev Beer Sheva 84105 Israel
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7
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Hrodmarsson HR, Garcia GA, Linnartz H, Nahon L. VUV photoionization dynamics of the C 60 buckminsterfullerene: 2D-matrix photoelectron spectroscopy in an astrophysical context. Phys Chem Chem Phys 2020; 22:13880-13892. [PMID: 32396927 DOI: 10.1039/d0cp01210f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the photoionization dynamics of the C60 buckminsterfullerene from threshold up to 14.0 eV recorded with VUV synchrotron radiation at the DESIRS beamline at the SOLEIL synchrotron. The recorded data is obtained using a double-imaging photoelectron photoion coincidence spectrometer and is presented as a two-dimensional photoelectron matrix which contains a wealth of spectroscopic data. We present these data in an astrophysical context which relates to (i) the threshold photoelectron spectrum which is compared to data relevant to the diffuse interstellar bands (DIBs), (ii) the kinetic photoelectron distribution at the Lyman-α line which is relevant to the dominant heating source in the ISM, and (iii) the absolute photoionization cross section of C60 up to approx. 10.5 eV. The photoelectron spectrum implies that the symmetry of the ground state is different than previous theoretical models have predicted, and this result is discussed in context of recent experimental and theoretical findings. Also presented are partial photoionization cross sections of the first two photoelectron bands and their anisotropy parameters. These data are compared with previous theoretical values and discussed where appropriate.
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8
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Mendez-Vega E, Sander W, Hemberger P. Isomer-Selective Threshold Photoelectron Spectra of Phenylnitrene and Its Thermal Rearrangement Products. J Phys Chem A 2020; 124:3836-3843. [PMID: 32208698 DOI: 10.1021/acs.jpca.0c01134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The photoionization of phenylnitrene was investigated by photoion mass-selected threshold photoelectron spectroscopy in the gas phase. Flash vacuum pyrolysis of phenyl azide at 480 °C produces the nitrene, which subsequently rearranges at higher temperatures affording three isomeric cyanocyclopentadienes, in contrast to low-temperature trapping experiments. Temperature control of the reactor and threshold photoelectron spectra allows for optimizing the generation of phenylnitrene or its thermal rearrangement products, as well as obtaining vibrational information for the corresponding ions. The adiabatic ionization energies (AIE) of the triplet nitrene (3A2) to the radical cation in its lowest-energy doublet (2B2) and quartet (4A1) spin states were determined to 8.29 ± 0.01 and 9.73 ± 0.01 eV, respectively. Vibrational frequencies of ring breathing modes were measured at 500 ± 80 and 484 ± 80 cm-1 for both the [Formula: see text](2B2) and [Formula: see text](4A1) cationic states, respectively. The AIE differ from the values previously reported; hence, we revise the doublet-quartet energy splitting of the phenylnitrene radical cation to 1.44 eV, in excellent agreement with composite methods and coupled cluster calculations, but considerably higher than the literature reference (1.1 eV).
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Affiliation(s)
- Enrique Mendez-Vega
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Wolfram Sander
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
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Hemberger P, van Bokhoven JA, Pérez-Ramírez J, Bodi A. New analytical tools for advanced mechanistic studies in catalysis: photoionization and photoelectron photoion coincidence spectroscopy. Catal Sci Technol 2020. [DOI: 10.1039/c9cy02587a] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
How can we detect reactive and elusive intermediates in catalysis to unveil reaction mechanisms? In this mini review, we discuss novel photoionization tools to support this quest.
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Affiliation(s)
- Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5232 Villigen PSI
- Switzerland
| | - Jeroen A. van Bokhoven
- Laboratory for Catalysis and Sustainable Chemistry
- Paul Scherrer Institute
- CH-5232 Villigen PSI
- Switzerland
- Institute for Chemical and Bioengineering
| | - Javier Pérez-Ramírez
- Institute for Chemical and Bioengineering
- Department of Chemistry and Applied Biosciences
- ETH Zurich
- Zurich
- Switzerland
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry
- Paul Scherrer Institute
- CH-5232 Villigen PSI
- Switzerland
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