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Rossi C, Gans B, Giuliani A, Jacovella U. Vacuum Ultraviolet Fingerprints as a New Way of Disentangling Tropylium/Benzylium Isomers. J Phys Chem Lett 2023; 14:8444-8447. [PMID: 37713678 DOI: 10.1021/acs.jpclett.3c01973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/17/2023]
Abstract
The two inseparable companions, tropylium (Tr+) and benzylium (Bz+), were interrogated by vacuum ultraviolet (VUV) radiation from 4.5 to 7.0 eV in an ion trap. These new fingerprints provide a new means of distinguishing these two intertwined C7H7+ isomers. In particular, the singular spectral signature of Tr+ in the VUV consists of a single strong electronic transition at ≈6 eV. To illustrate this diagnostic tool, we shed light on the structure of the C7H7+ intermediate that is ubiquitous when using commercial atmospheric pressure photoionization (APPI) sources. We have identified its structure as the 7-membered ring Tr+, which contradicts some previous beliefs.
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Affiliation(s)
- Corentin Rossi
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - Bérenger Gans
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
| | - Alexandre Giuliani
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette, France
- INRAE, UAR1008, Transform Department, Rue de la Géraudiére, BP 71627, 44316 Nantes, France
| | - Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France
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2
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Calvin A, Eierman S, Peng Z, Brzeczek M, Satterthwaite L, Patterson D. Single molecule infrared spectroscopy in the gas phase. Nature 2023; 621:295-299. [PMID: 37380028 PMCID: PMC10499601 DOI: 10.1038/s41586-023-06351-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 06/21/2023] [Indexed: 06/30/2023]
Abstract
Spectroscopy is a key analytical tool that provides valuable insight into molecular structure and is widely used to identify chemical samples. Tagging spectroscopy is a form of action spectroscopy in which the absorption of a single photon by a molecular ion is detected via the loss of a weakly attached, inert 'tag' particle (for example, He, Ne, N2)1-3. The absorption spectrum is derived from the tag loss rate as a function of incident radiation frequency. So far, all spectroscopy of gas phase polyatomic molecules has been restricted to large molecular ensembles, thus complicating spectral interpretation by the presence of multiple chemical and isomeric species. Here we present a novel tagging spectroscopic scheme to analyse the purest possible sample: a single gas phase molecule. We demonstrate this technique with the measurement of the infrared spectrum of a single gas phase tropylium (C7H7+) molecular ion. The high sensitivity of our method revealed spectral features not previously observed using traditional tagging methods4. Our approach, in principle, enables analysis of multicomponent mixtures by identifying constituent molecules one at a time. Single molecule sensitivity extends action spectroscopy to rare samples, such as those of extraterrestrial origin5,6, or to reactive reaction intermediates formed at number densities that are too low for traditional action methods.
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Affiliation(s)
- Aaron Calvin
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Scott Eierman
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Zeyun Peng
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Merrell Brzeczek
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Lincoln Satterthwaite
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - David Patterson
- Department of Physics, University of California, Santa Barbara, CA, USA.
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3
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Zhao Y, Huang P, Li L, Zhan Y, Wang K, Yang H, Jin J, Chen Y, Liu Y, Sheng L, Chen J, Cao M. Vacuum ultraviolet photoionization and dissociative photoionization of toluene: Experimental and theoretical insights. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2021; 27:166-180. [PMID: 34612719 DOI: 10.1177/14690667211042707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The photoionization and dissociative photoionization of toluene have been studied using synchrotron radiation vacuum ultraviolet light with photon energy in the range of 8.50-25.50 eV. The ionization energies (8.82 eV) and double ionization energies (23.80 eV) of toluene as well as the appearance energies for its major fragments C7H7+ (11.17/10.71 eV), C6H5+ (13.73 eV), C5H6+ (13.58/12.50 eV), C5H5+ (16.23 eV), C4H5+ (15.64 eV), C4H4+ (16.10 eV) and C4H3+ (17.11 eV) are determined, respectively by using photoionization efficiency spectrometry. With the help of experimental and theoretical results, seven dissociative photoionization channels have been proposed: C7H7+ + H, C6H5+ + CH3, C5H6+ + C2H2, C5H5+ + C2H2 + H, C4H5+ + C3H3, C4H4+ + C3H4 and C4H3+ + C3H4 + H. In addition, the geometries of the intermediates, transition states and products involved in these photoionization and dissociative photoionization processes have been performed at the B3LYP/6-311++G(d, p) level. The mechanisms of dissociative photoionization of toluene and the intermediates and transition states involved are discussed in detail. Generally speaking, the experimental results are in agreement with theoretical calculations in this work and published literature results. Especially the mechanisms of dissociative photoionization to C4H5+, C4H4+ and C4H3+ were discussed for the first time in this work. This investigation may provide useful information on understanding the photoionization and dissociative photoionization of toluene.
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Affiliation(s)
- Yujie Zhao
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
- National Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, 12652University of Science and Technology of China, P.R. China
| | - Pei Huang
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Li Li
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Yousheng Zhan
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Ke Wang
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Haohang Yang
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Jianhui Jin
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Yuqian Chen
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Yibao Liu
- School of Nuclear Science and Engineering, 468741East China University of Technology, P.R. China
| | - Liusi Sheng
- National Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, 12652University of Science and Technology of China, P.R. China
| | - Jun Chen
- National Synchrotron Radiation Laboratory, School of Nuclear Science and Technology, 12652University of Science and Technology of China, P.R. China
| | - Maoqi Cao
- School of Chemistry and Chemical Engineering, 56700Qiannan Normal University for Nationalities, P.R. China
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4
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Jacovella U, Scholz MS, Bieske EJ. Electronic Spectrum of the Tropylium Cation in the Gas Phase. J Phys Chem Lett 2020; 11:8867-8872. [PMID: 32990444 DOI: 10.1021/acs.jpclett.0c02430] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The structure and properties of the tropylium cation (C7H7+) have enthralled chemists since the prediction by Hückel in 1931 of the remarkable stability for cyclic, aromatic molecules containing six π-electrons. However, probing and understanding the excited electronic states of the isolated tropylium cation have proved challenging, as the accessible electronic transitions are weak, and there are difficulties in creating appreciable populations of the tropylium cation in the gas phase. Here, we present the first gas-phase S1 ←S0 electronic spectrum of the tropylium cation, recorded by resonance-enhanced photodissociation of weakly bound tropylium-Ar complexes. We demonstrate that the intensity of the symmetry-forbidden S1 ←S0 transition arises from Herzberg-Teller vibronic coupling between the S1 and S2 electronic states mediated by vibrational modes of e2' and e3' symmetry. The main geometry change upon excitation involves elongation of the C-C bonds. Multiconfigurational ab initio calculations predict that the S1 excited state is affected by the dynamical Jahn-Teller effect, which should lead to the appearance of additional weak bands that may be apparent in higher-resolution electronic spectra.
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Affiliation(s)
- Ugo Jacovella
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Michael S Scholz
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
| | - Evan J Bieske
- School of Chemistry, The University of Melbourne, Victoria 3010, Australia
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Roithová J, Jašík J, Del Pozo Mellado JJ, Gerlich D. Electronic spectra of ions of astrochemical interest: from fast overview spectra to high resolution. Faraday Discuss 2019; 217:98-113. [PMID: 31016298 PMCID: PMC8639220 DOI: 10.1039/c8fd00196k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 12/12/2018] [Indexed: 11/21/2022]
Abstract
The combination of cryogenic ion traps with suitable light sources and standard tools of mass spectrometry has led to many innovative applications in previous years. This paper presents the combination of our versatile instrument with a supercontinuum laser for the rapid identification of ions that might be of special interest, e.g. as candidates for diffuse interstellar bands carriers. Using a linear wire quadrupole ion trap at 3 K, routine He-tagging, long irradiation times, and the brilliance and wide spectral range of a crystal fiber laser, mass selected ions have been exposed to spectral fluencies larger than 10 mJ (nm cm2)-1. These conditions result in an unsurpassed sensitivity, allowing us to find out within a few minutes and with nm accuracy, where photo absorption occurs with cross sections above 10-18 cm2. In this contribution, we present a variety of ions, probed between 420 and 720 nm. They have been generated by electron- or electrospray ionization of (polycyclic) aromatic hydrocarbons. For selected candidates, we recorded spectra with higher resolution and in the IR range. The anthracene dication has been selected to present a detailed analysis of our new results.
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Affiliation(s)
- Jana Roithová
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands.
| | - Juraj Jašík
- Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 2030/8, 128 43 Prague 2, Czech Republic
| | - Jesus J Del Pozo Mellado
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, Netherlands.
| | - Dieter Gerlich
- Department of Physics, University of Technology, 09107 Chemnitz, Germany
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Jusko P, Simon A, Banhatti S, Brünken S, Joblin C. Direct Evidence of the Benzylium and Tropylium Cations as the Two Long-Lived Isomers of C 7 H 7. Chemphyschem 2018; 19:3182-3185. [PMID: 30238585 PMCID: PMC6420061 DOI: 10.1002/cphc.201800744] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Indexed: 11/12/2022]
Abstract
Disentangling the isomeric structure of C7 H7 + is a longstanding experimental issue. We report here the full mid-infrared vibrational spectrum of C7 H7 + tagged with Ne obtained with infrared-predissociation spectroscopy at 10 K. Saturation depletion measurements were used to assign the contribution of benzylium and tropylium isomers and demonstrate that no other isomer is involved. Recorded spectral features compare well with density functional theory calculations. This opens perspectives for a better understanding and control of the formation paths leading to either tropylium or benzylium ions.
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Affiliation(s)
- Pavol Jusko
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
| | - Aude Simon
- Laboratoire de Chimie et Physique Quantiques LCPQ/IRSAMC, Université de Toulouse (UPS) and CNRS, 118 Route de Narbonne, 31062 Toulouse, France
| | - Shreyak Banhatti
- I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
| | - Sandra Brünken
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525 ED, Nijmegen, The Netherlands
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie (IRAP), Université de Toulouse (UPS), CNRS, CNES, 9 Av. du Colonel Roche, 31028 Toulouse Cedex 4, France
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7
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Wagner JP, McDonald DC, Duncan MA. Mid-Infrared Spectroscopy of C 7H 7+ Isomers in the Gas Phase: Benzylium and Tropylium. J Phys Chem Lett 2018; 9:4591-4595. [PMID: 30059230 DOI: 10.1021/acs.jpclett.8b02121] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Both prominent C7H7+ isomers, the benzylium and the tropylium cations, were generated in an electrical discharge/supersonic expansion from toluene and cycloheptatriene precursors. Their infrared spectra were measured in the region of 1000-3500 cm-1 using photodissociation of the respective argon- and nitrogen-tagged complexes with a broadly tunable OPO/OPA laser system. Spectral signatures of both isomers were observed independent of the precursor, albeit in different relative intensities. The spectra were assigned based on scaled harmonic B3LYP-D3/cc-pVTZ frequency computations and comparisons to previous experimental studies. Consistent with its high symmetry, only two bands were observed for the (nitrogen-tagged) tropylium ion at 3036 and 1477 cm-1, corresponding to C-H stretching and C-C-H deformation/C═C stretching vibrations, respectively. Furthermore, the C-H stretching region of the benzylium ion is reported for the first time.
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Affiliation(s)
- J Philipp Wagner
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
| | - David C McDonald
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
| | - Michael A Duncan
- Department of Chemistry , University of Georgia , 140 Cedar Street , Athens , Georgia 30602 , United States
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8
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Féraud G, Dedonder-Lardeux C, Jouvet C, Marceca E. Photodissociation UV–Vis Spectra of Cold Protonated Azobenzene and 4-(Dimethylamino)azobenzene and Their Benzenediazonium Cation Fragment. J Phys Chem A 2016; 120:3897-905. [DOI: 10.1021/acs.jpca.6b03505] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Géraldine Féraud
- CNRS, Aix-Marseille Université, PIIM UMR 7365, Avenue Escadrille
Normandie-Niémen, 13397 Marseille Cedex 20, France
| | - Claude Dedonder-Lardeux
- CNRS, Aix-Marseille Université, PIIM UMR 7365, Avenue Escadrille
Normandie-Niémen, 13397 Marseille Cedex 20, France
| | - Christophe Jouvet
- CNRS, Aix-Marseille Université, PIIM UMR 7365, Avenue Escadrille
Normandie-Niémen, 13397 Marseille Cedex 20, France
| | - Ernesto Marceca
- INQUIMAE,
FCEN-UBA, Ciudad Universitaria, 3er piso, Pabellón II, C1428EGA Buenos Aires, Argentina
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9
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Schütz M, Bouchet A, Chiavarino B, Crestoni ME, Fornarini S, Dopfer O. Effects of Aromatic Fluorine Substitution on Protonated Neurotransmitters: The Case of 2-Phenylethylamine. Chemistry 2016; 22:8124-36. [DOI: 10.1002/chem.201600798] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Markus Schütz
- Institut für Optik und Atomare Physik; Technische Universität Berlin; Hardenbergstr. 36 10623 Berlin Germany
| | - Aude Bouchet
- Institut für Optik und Atomare Physik; Technische Universität Berlin; Hardenbergstr. 36 10623 Berlin Germany
| | - Barbara Chiavarino
- Dipartimento di Chimica e Tecnologie del Farmaco; Sapienza Università di Roma “La Sapienza”; P. le A. Moro 5 00185 Roma Italy
| | - Maria Elisa Crestoni
- Dipartimento di Chimica e Tecnologie del Farmaco; Sapienza Università di Roma “La Sapienza”; P. le A. Moro 5 00185 Roma Italy
| | - Simonetta Fornarini
- Dipartimento di Chimica e Tecnologie del Farmaco; Sapienza Università di Roma “La Sapienza”; P. le A. Moro 5 00185 Roma Italy
| | - Otto Dopfer
- Institut für Optik und Atomare Physik; Technische Universität Berlin; Hardenbergstr. 36 10623 Berlin Germany
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Wang LS. Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions. J Chem Phys 2015; 143:040901. [DOI: 10.1063/1.4927086] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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11
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Savee JD, Zádor J, Hemberger P, Sztáray B, Bodi A, Osborn DL. Threshold photoelectron spectrum of the benzyl radical. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1021398] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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12
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Dedonder C, Féraud G, Jouvet C. Communication: Identification of daughter ions through their electronic spectroscopy at low temperature. J Chem Phys 2014; 141:131101. [DOI: 10.1063/1.4896981] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Claude Dedonder
- Aix-Marseille Université, CNRS, PIIM, UMR-7345, Marseille Cedex 20, France
| | - Géraldine Féraud
- Aix-Marseille Université, CNRS, PIIM, UMR-7345, Marseille Cedex 20, France
| | - Christophe Jouvet
- Aix-Marseille Université, CNRS, PIIM, UMR-7345, Marseille Cedex 20, France
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13
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Féraud G, Dedonder C, Jouvet C, Inokuchi Y, Haino T, Sekiya R, Ebata T. Development of Ultraviolet-Ultraviolet Hole-Burning Spectroscopy for Cold Gas-Phase Ions. J Phys Chem Lett 2014; 5:1236-1240. [PMID: 26274477 DOI: 10.1021/jz500478w] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A new ultraviolet-ultraviolet hole-burning (UV-UV HB) spectroscopic scheme has been developed for cold gas-phase ions in a quadrupole ion trap (QIT) connected with a time-of-flight (TOF) mass spectrometer. In this method, a pump UV laser generates a population hole for the ions trapped in the cold QIT, and a second UV laser (probe) monitors the population hole for the ions extracted to the field-free region of the TOF mass spectrometer. Here, the neutral fragments generated by the UV dissociation of the ions with the second laser are detected. This UV-UV HB spectroscopy was applied to protonated dibenzylamine and to protonated uracil. Protonated uracil exhibits two strong electronic transitions; one has a band origin at 31760 cm(-1) and the other at 39000 cm(-1). From the UV-UV HB measurement and quantum chemical calculations, the lower-energy transition is assigned to the enol-keto tautomer and the higher-energy one to the enol-enol tautomer.
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Affiliation(s)
- Géraldine Féraud
- †Physique des Interactions Ioniques et Moleculaires (PIIM) UMR 7345, CNRS, Aix Marseille Université, 13397 Marseille Cedex, France
| | - Claude Dedonder
- †Physique des Interactions Ioniques et Moleculaires (PIIM) UMR 7345, CNRS, Aix Marseille Université, 13397 Marseille Cedex, France
| | - Christophe Jouvet
- †Physique des Interactions Ioniques et Moleculaires (PIIM) UMR 7345, CNRS, Aix Marseille Université, 13397 Marseille Cedex, France
| | - Yoshiya Inokuchi
- ‡Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Takeharu Haino
- ‡Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Ryo Sekiya
- ‡Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
| | - Takayuki Ebata
- ‡Department of Chemistry, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan
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