1
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Rouquet E, Dupont J, Lepere V, Garcia GA, Nahon L, Zehnacker A. Conformer-Selective Photoelectron Circular Dichroism. Angew Chem Int Ed Engl 2024; 63:e202401423. [PMID: 38442011 DOI: 10.1002/anie.202401423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 03/07/2024]
Abstract
Conformational flexibility and chirality both play a key role in molecular recognition. It is therefore very useful to develop spectroscopic methods that simultaneously probe both properties. It has been theoretically predicted that photoelectron circular dichroism (PECD) should be very sensitive to conformational isomerism. However, experimental proof has been less forthcoming and only exists for a very few favorable cases. Here, we present a new PECD scheme based on resonance-enhanced two-photon ionization (RE2PI) using UV/Vis nanosecond laser excitations. The spectral resolution obtained thereby guarantees conformer-selectivity by inducing resonant conformer-specific ππ* S1←S0 transitions. We apply this experimental scheme to the study of chiral 1-indanol, which exists in two conformers linked by a ring inversion and defined by the position of the hydroxyl group, namely axial and equatorial. We show that the PECD of the equatorial and axial forms considerably differ in sign, magnitude and shape. We also discuss the influence of the total ionization energy, vibronic excitation of intermediate and final states, and relative polarization of the excitation and ionization lasers. Conformer-specificity adds a new dimension to the applications of PECD in analytical chemistry addressing now the general case of floppy systems.
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Affiliation(s)
- Etienne Rouquet
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Valeria Lepere
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Laurent Nahon
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192, Gif sur Yvette, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
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2
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Wu X, Zhang C, Gu X, Fittschen C, Loison JC, Chowdhury MR, Garcia GA, Nahon L, Tang X. Photoionization and dissociative photoionization of acetaldehyde in the 10.0-13.7 eV range by synchrotron photoelectron photoion coincidence spectroscopy. Chemphyschem 2024:e202400208. [PMID: 38594204 DOI: 10.1002/cphc.202400208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 04/09/2024] [Accepted: 04/09/2024] [Indexed: 04/11/2024]
Abstract
Photoionization and dissociative photoionization of acetaldehyde (CH3CHO) in the 10.0‒13.7 eV energy range are studied by using synchrotron radiation double imaging photoelectron photoion coincidence spectroscopy (i2PEPICO). The X2A' and A2A" electronic states of CH3CHO+ as well as the Franck-Condon gap region between these two states have been populated with several vibrational sequences and assigned in the high-resolution slow photoelectron spectrum (SPES). The adiabatic ionization energies (AIEs) of the X2A' and A2A" states are measured at 10.228 ± 0.006 and 12.52 ± 0.05 eV, respectively. The present results show that the X2A' state is a stable state while the A2A" state is fully dissociative to produce CH3CO+, CHO+ and CH4+ fragment ions. The 0K appearance energies (AE0K) of CH3CO+ and CHO+ fragment ions are determined through the modeling of the breakdown diagram, i.e., AE0K(CH3CO+) = 10.89 ± 0.01 eV (including a reverse barrier of ~ 0.19 eV) and AE0K(CHO+) = 11.54 ± 0.05 eV. In addition, the dissociation mechanisms of CH3CHO+ including statistical dissociation, direct bond breaking and isomerization are discussed with the support of the calculated dissociation limits and transition state energies.
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Affiliation(s)
- Xiangkun Wu
- Chinese Academy of Sciences Hefei Institutes of Physical Science, Anhui Institute of Optics and Fine Mechanics, CHINA
| | - Cuihong Zhang
- Chinese Academy of Sciences Hefei Institutes of Physical Science, Anhui Institute of Optics and Fine Mechanics, CHINA
| | - Xuejun Gu
- Chinese Academy of Sciences Hefei Institutes of Physical Science, Anhui Institute of Optics and Fine Mechanics, CHINA
| | - Christa Fittschen
- University of Lille, Physicochimie des Processus de Combustion et de l'Atmosphère, FRANCE
| | | | | | | | | | - Xiaofeng Tang
- Hefei Institutes of Physical Science, Chinese Academy of Science, Anhui Institute of Optics and Fine Mechanics, Shushanhu Road 350, 230031, Hefei, CHINA
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3
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Chen NL, Gans B, Boyé-Péronne S, Hartweg S, Garcia GA, Loison JC. Experimental characterization of SiCH+via single-photon ionization of gas-phase SiCH. J Chem Phys 2024; 160:114310. [PMID: 38501474 DOI: 10.1063/5.0198424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 02/27/2024] [Indexed: 03/20/2024] Open
Abstract
SiCH and its cation have consistently emerged as predicted species in models of silicon chemistry within the interstellar medium, although they remain unobserved in space. Hindered by their intrinsic instability, no spectroscopic insights have been gleaned concerning the SiCH+ cation. In this study, we present experimental measurements on the SiCH+ cation through single-photon ionization spectroscopy of the SiCH radical within the 8.0-11.0 eV range. Gas-phase SiCH radicals were generated through chemical reactions involving CHx (x = 0-3) and SiHy (y = 0-3) within a microwave discharge flow-tube reactor. Employing a double imaging photoelectron/photoion coincidence spectrometer on the DESIRS beamline at the SOLEIL synchrotron, we recorded mass-selected ion yield and photoelectron spectra. From the analysis of the photoelectron spectrum supported by ab initio calculations and Franck-Condon simulations, the adiabatic ionization energies for the transitions from the X2Π ground electronic state of SiCH toward the X+3Σ- and A+3Π electronic states of SiCH+ have been derived [8.935(6) and 10.664(6) eV, respectively, without spin-orbit correction]. The contribution from the less stable isomer HSiC has been explored in our analysis and ruled out in our experiments.
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Affiliation(s)
- N L Chen
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, F-91405 Orsay, France
| | - B Gans
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, F-91405 Orsay, France
| | - S Boyé-Péronne
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, F-91405 Orsay, France
| | - S Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, F-91192 Gif sur Yvette, France
| | - G A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, F-91192 Gif sur Yvette, France
| | - J-C Loison
- Institut des Sciences Moléculaires, CNRS, Université de Bordeaux, F-33400 Talence, France
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Cano Ardila FE, Nagaraju S, Tranter RS, Garcia GA, Desclaux A, Roque Ccacya A, Chaumeix N, Comandini A. External standard calibration method for high-repetition-rate shock tube kinetic studies with synchrotron-based time-of-flight mass spectrometry. Analyst 2024; 149:1586-1596. [PMID: 38289286 PMCID: PMC10895696 DOI: 10.1039/d3an00819c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
The signal levels observed from mass spectrometers coupled by molecular beam sampling to shock tubes are impacted by dynamic pressures in the spectrometer due to rapid pressure changes in the shock tube. Accounting for the impact of the pressure changes is essential if absolute concentrations of species are to be measured. Obtaining such a correction for spectrometers operated with vacuum ultra violet photoionization has been challenging. We present here a new external calibration method which uses VUV-photoionization of CO2 to develop time-dependent corrections to species concentration/time profiles from which kinetic data can be extracted. The experiments were performed with the ICARE-HRRST (high repetition rate shock tube) at the DESIRS beamline of synchrotron SOLEIL. The calibration experiments were performed at temperatures and pressures behind reflected shock waves of 1376 ± 12 K and 6.6 ± 0.1 bar, respectively. Pyrolytic experiments with two aromatic species, toluene (T5 = 1362 ± 22 K, P5 = 6.6 ± 0.2 bar) and ethylbenzene (T5 = 1327 ± 18 K, P5 = 6.7 ± 0.2 bar), are analyzed to test the method. Time dependent concentrations for molecular and radical species were corrected with the new method. The resulting signals were compared with chemical kinetic simulations using a recent mechanism for pyrolytic formation of polycyclic aromatic hydrocarbons. Excellent agreement was obtained between the experimental data and simulations, without adjustment of the model, demonstrating the validity of the external calibration method.
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Affiliation(s)
- Fabian E Cano Ardila
- CNRS-INSIS, I.C.A.R.E., 1C Avenue de la recherche scientifique, 45071 Orléans cedex 2, France.
| | - Sharath Nagaraju
- CNRS-INSIS, I.C.A.R.E., 1C Avenue de la recherche scientifique, 45071 Orléans cedex 2, France.
| | - Robert S Tranter
- Chemical Sciences and Engineering Department, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette, France
| | - Anthony Desclaux
- CNRS-INSIS, I.C.A.R.E., 1C Avenue de la recherche scientifique, 45071 Orléans cedex 2, France.
| | - Anthony Roque Ccacya
- CNRS-INSIS, I.C.A.R.E., 1C Avenue de la recherche scientifique, 45071 Orléans cedex 2, France.
| | - Nabiha Chaumeix
- CNRS-INSIS, I.C.A.R.E., 1C Avenue de la recherche scientifique, 45071 Orléans cedex 2, France.
| | - Andrea Comandini
- CNRS-INSIS, I.C.A.R.E., 1C Avenue de la recherche scientifique, 45071 Orléans cedex 2, France.
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5
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Ganjitabar H, Hadidi R, Garcia GA, Nahon L, Powis I. Analysis of the volatile monoterpene composition of citrus essential oils by photoelectron spectroscopy employing continuously monitored dynamic headspace sampling. Analyst 2023; 148:6228-6240. [PMID: 37987708 DOI: 10.1039/d3an01448g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
A new photoelectron spectroscopic method permitting a quantitative analysis of the volatile headspace of several essential oils is presented and discussed. In particular, we focus on the monoterpene compounds, which are known to be the dominant volatile components in many such oils. The photoelectron spectra of the monoterpene constituents may be effectively isolated by accepting for analysis only those electrons that accompany the production of m/z = 136 ions, and by using low photon energies that restrict cation fragmentation. The monoterpene isomers are then identified and quantified by regression modelling using a library of terpene standard spectra. An advantage of this approach is that pre-concentration of the volatile vapour is not required, and all steps are performed at ambient temperature, avoiding the possible deleterious effects (such as isomerisation/decomposition) that may sometimes arise in gas chromatographic (GC) procedures. As a proof-of-principle demonstration, three citrus oils (lemon, lime, bergamot) are analysed with this approach and the results are compared with reported GC composition profiles obtained for these oils. Potential advantages of the methodology that include multiplex detection and real-time, in situ analysis are identified and discussed. Alternative and faster experimental implementations concerning laboratory-based ionization and detection schemes are proposed and considered, as is the possibility of a straightforward extension towards simultaneous determination of enantiomeric excesses.
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Affiliation(s)
- Hassan Ganjitabar
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - Rim Hadidi
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
| | - Gustavo A Garcia
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
| | - Laurent Nahon
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
| | - Ivan Powis
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, UK.
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Jacovella U, Ruscic B, Chen NL, Le HL, Boyé-Péronne S, Hartweg S, Chowdhury MR, Garcia GA, Loison JC, Gans B. Refining the thermochemical properties of CF, SiF, and their cations by combining photoelectron spectroscopy, quantum chemical calculations, and the Active Thermochemical Tables approach. Phys Chem Chem Phys 2023; 25:30838-30847. [PMID: 37877862 DOI: 10.1039/d3cp04244h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Fluorinated species have a pivotal role in semiconductor material chemistry and some of them have been detected beyond the Earth's atmosphere. Achieving good energy accuracy on fluorinated species using quantum chemical calculations has long been a challenge. In addition, obtaining direct experimental thermochemical quantities has also proved difficult. Here, we report the threshold photoelectron and photoion yield spectra of SiF and CF radicals generated with a fluorine reactor. The spectra were analysed with the support of ab initio calculations, resulting in new experimental values for the adiabatic ionisation energies of both CF (9.128 ± 0.006 eV) and SiF (7.379 ± 0.009 eV). Using these values, the underlying thermochemical network of Active Thermochemical Tables was updated, providing further refined enthalpies of formation and dissociation energies of CF, SiF, and their cationic counterparts.
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Affiliation(s)
- Ugo Jacovella
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France.
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
| | - Ning L Chen
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France.
| | - Hai-Linh Le
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France.
| | - Séverine Boyé-Péronne
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France.
| | - Sebastian Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette, France
| | | | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, 91192 Saint Aubin, Gif-sur-Yvette, France
| | | | - Bérenger Gans
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, 91405 Orsay, France.
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7
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Singh DP, De Oliveira N, Garcia GA, Vredenborg A, Powis I. Corrigendum: Experimental and Theoretical Investigation of the 3sp(d) Rydberg States of Fenchone by Polarized Laser Resonance-Enhanced-Multiphoton-Ionization and Fourier Transform VUV Absorption Spectroscopy. Chemphyschem 2023; 24:e202300443. [PMID: 37876347 DOI: 10.1002/cphc.202300443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
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8
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Rouquet E, Roy Chowdhury M, Garcia GA, Nahon L, Dupont J, Lepère V, Le Barbu-Debus K, Zehnacker A. Induced photoelectron circular dichroism onto an achiral chromophore. Nat Commun 2023; 14:6290. [PMID: 37813848 PMCID: PMC10562374 DOI: 10.1038/s41467-023-42002-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 09/25/2023] [Indexed: 10/11/2023] Open
Abstract
An achiral chromophore can acquire a chiral spectroscopic signature when interacting with a chiral environment. This so-called induced chirality is documented in electronic or vibrational circular dichroism, which arises from the coupling between electric and magnetic transition dipoles. Here, we demonstrate that a chiroptical response is also induced within the electric dipole approximation by observing the asymmetric scattering of a photoelectron ejected from an achiral chromophore in interaction with a chiral host. In a phenol-methyloxirane complex, removing an electron from an achiral aromatic π orbital localised on the phenol moiety results in an intense and opposite photoelectron circular dichroism (PECD) for the two enantiomeric complexes with (R) and (S) methyloxirane, evidencing the long-range effect (~5 Å) of the scattering chiral potential. This induced chirality has important structural and analytical implications, discussed here in the context of growing interest in laser-based PECD, for in situ, real time enantiomer determination.
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Affiliation(s)
- Etienne Rouquet
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190, St Aubin, France
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | | | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190, St Aubin, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, F-91190, St Aubin, France.
| | - Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Valéria Lepère
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Katia Le Barbu-Debus
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405, Orsay, France.
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Gans B, Liévin J, Halvick P, Chen NL, Boyé-Péronne S, Hartweg S, Garcia GA, Loison JC. Single-photon ionization of SiC in the gas phase: experimental and ab initio characterization of SiC . Phys Chem Chem Phys 2023; 25:23568-23578. [PMID: 37656136 DOI: 10.1039/d3cp02775a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
We report the first experimental observation of single-photon ionization transitions of the SiC radical between 8.0 and 11.0 eV performed on the DESIRS beamline at the SOLEIL synchrotron facility. The SiC radical, very difficult to synthesize in the gas phase, was produced through chemical reactions between CHx (x = 0-3) and SiHy (y = 0-3) in a continuous microwave discharge flow tube, the CHx and SiHy species being formed by successive hydrogen-atom abstractions induced by fluorine atoms on methane and silane, respectively. Mass-selected ion yield and photoelectron spectra were recorded as a function of photon energy using a double imaging photoelectron/photoion coincidence spectrometer. The photoelectron spectrum enables the first direct experimental determinations of the X+ 4Σ- ← X 3Π and 1+ 2Π ← X 3Π adiabatic ionization energies of SiC (8.978(10) eV and 10.216(24) eV, respectively). Calculated spectra based on Franck-Condon factors are compared with the experimental spectra. These spectra were obtained by solving the rovibrational Hamiltonian, using the potential energy curves calculated at the multireference single and double configuration interaction level with Davidson correction (MRCI + Q) and the aug-cc-pV5Z basis set. MRCI + Q calculations including the core and core-valence electron correlation were performed using the aug-cc-pCV6Z basis set to predict the spectroscopic properties of the six lowest electronic states of SiC+. Complete basis set extrapolations and relativistic energy corrections were also included in the determination of the energy differences characterizing the photoionization process. Using our experimental and theoretical results, we derived semi-experimental values for the five lowest ionization energies of SiC.
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Affiliation(s)
- B Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, F-91405 Orsay, France.
| | - J Liévin
- Spectroscopy, Quantum Chemistry and Atmospheric Remote Sensing, Université Libre de Bruxelles, CP 160/09, B-1050 Bruxelles, Belgium
| | - P Halvick
- Institut des Sciences Moléculaires, CNRS, Université de Bordeaux, F-33400 Talence, France
| | - N L Chen
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, F-91405 Orsay, France.
| | - S Boyé-Péronne
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, F-91405 Orsay, France.
| | - S Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, F-91192 Gif sur Yvette, France
| | - G A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, F-91192 Gif sur Yvette, France
| | - J-C Loison
- Institut des Sciences Moléculaires, CNRS, Université de Bordeaux, F-33400 Talence, France
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10
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Zhang H, Bolshakov A, Meena R, Garcia GA, Dugulan AI, Parastaev A, Li G, Hensen EJM, Kosinov N. Revealing Active Sites and Reaction Pathways in Methane Non-Oxidative Coupling over Iron-Containing Zeolites. Angew Chem Int Ed Engl 2023:e202306196. [PMID: 37395384 DOI: 10.1002/anie.202306196] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Indexed: 07/04/2023]
Abstract
Non-oxidative coupling of methane is a promising route to obtain ethylene directly from natural gas. We synthesized siliceous [Fe]zeolites with MFI and CHA topologies and found that they display high selectivity (>90 % for MFI and >99 % for CHA) to ethylene and ethane among gas-phase products. Deactivated [Fe]zeolites can be regenerated by burning coke in air. In situ X-ray absorption spectroscopy demonstrates that the isolated Fe3+ centers in zeolite framework of fresh catalysts are reduced during the reaction to the active sites, including Fe2+ species and Fe (oxy)carbides dispersed in zeolite pores. Photoelectron photoion coincidence spectroscopy results show that methyl radicals are the reaction intermediates formed upon methane activation. Ethane is formed by methyl radical coupling, followed by its dehydrogenation to ethylene. Based on the observation of intermediates including allene, vinylacetylene, 1,3-butadiene, 2-butyne, and cyclopentadiene over [Fe]MFI, a reaction network is proposed leading to polyaromatic species. Such reaction intermediates are not observed over the small-pore [Fe]CHA, where ethylene and ethane are the only gas-phase products.
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Affiliation(s)
- Hao Zhang
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Aleksei Bolshakov
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Raghavendra Meena
- Biobased Chemistry and Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
- Laboratory of Organic Chemistry, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Gustavo A Garcia
- Synchrotron SOLEIL L'Orme des Merisiers, St. Aubin BP 48, 91192, Gif sur Yvette, France
| | - A Iulian Dugulan
- Fundamental Aspects of Materials and Energy, Department of Radiation Science and Technology, Delft University of Technology, Mekelweg 15, 2629 JB, Delft, The Netherlands
| | - Alexander Parastaev
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Guanna Li
- Biobased Chemistry and Technology, Wageningen University & Research, Bornse Weilanden 9, 6708 WG, Wageningen, The Netherlands
- Laboratory of Organic Chemistry, Wageningen University & Research, Stippeneng 4, 6708 WE, Wageningen, The Netherlands
| | - Emiel J M Hensen
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
| | - Nikolay Kosinov
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands
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11
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Hartweg S, Barnes J, Yoder BL, Garcia GA, Nahon L, Miliordos E, Signorell R. Solvated dielectrons from optical excitation: An effective source of low-energy electrons. Science 2023:eadh0184. [PMID: 37228229 DOI: 10.1126/science.adh0184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 05/12/2023] [Indexed: 05/27/2023]
Abstract
Low-energy electrons dissolved in liquid ammonia or aqueous media are powerful reducing agents that promote challenging reduction reactions, but can also cause radiation damage to biological tissue. Knowledge of the underlying mechanistic processes remains incomplete, in particular with respect to the details and energetics of the electron transfer steps. Here, we show how ultraviolet (UV) photoexcitation of metal-ammonia clusters could be used to generate tunable low-energy electrons in situ. Specifically, we identified UV light-induced generation of spin-paired solvated dielectrons and their subsequent relaxation by an unconventional electron-transfer-mediated decay as an efficient low-energy electron source. The process is robust and straightforward to induce, with the prospect of improving our understanding of radiation damage and fostering mechanistic studies of solvated electron reduction reactions.
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Affiliation(s)
- Sebastian Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
- Institute of Physics, University of Freiburg, Hermann-Herder-Straße 3a, 79104 Freiburg, Germany
| | - Jonathan Barnes
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Bruce L Yoder
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
| | - Evangelos Miliordos
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, AL, USA
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
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12
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Hartweg S, Hochlaf M, Garcia GA, Nahon L. Photoionization Dynamics and Proton Transfer within the Adenine-Thymine Nucleobase Pair. J Phys Chem Lett 2023; 14:3698-3705. [PMID: 37040591 DOI: 10.1021/acs.jpclett.3c00564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Studying the stability of hydrogen-bonded nucleobase pairs, at the heart of the genetic code, is of utmost importance for an in-depth understanding of basic mechanisms of life and biomolecular evolution. We present here a VUV single photon ionization dynamic study of the nucleobase pair adenine-thymine (AT), revealing its ionization and dissociative ionization thresholds via double imaging electron/ion coincidence spectroscopy. The experimental data, consisting of cluster mass-resolved threshold photoelectron spectra and photon energy-dependent ion kinetic energy release distributions, allow the unambiguous distinction of the dissociation of AT into protonated adenine AH+ and a dehydrogenated thymine radical T(-H) from dissociative ionization processes of other nucleobase clusters. Comparison to high-level ab initio calculations indicates that our experimental observations can be explained by a single hydrogen-bonded conformer present in our molecular beam and allows the estimation of an upper limit of the barrier of the proton transfer in the ionized AT pair.
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Affiliation(s)
- Sebastian Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
- University of Freiburg, Institute of Physics, Hermann-Herder-Straße 3, 79104 Freiburg, Germany
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes, 77454 Champs sur Marne, France
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
| | - Laurent Nahon
- Synchrotron Soleil, L'Orme des Merisiers, Départementale 128, 91190 St Aubin, France
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13
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Liutkova A, Zhang H, Simons JFM, Mezari B, Mirolo M, Garcia GA, Hensen EJM, Kosinov N. Ca Cations Impact the Local Environment inside HZSM-5 Pores during the Methanol-to-Hydrocarbons Reaction. ACS Catal 2023; 13:3471-3484. [PMID: 36970466 PMCID: PMC10028611 DOI: 10.1021/acscatal.3c00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 02/10/2023] [Indexed: 02/25/2023]
Abstract
The methanol-to-hydrocarbons (MTH) process is an industrially relevant method to produce valuable light olefins such as propylene. One of the ways to enhance propylene selectivity is to modify zeolite catalysts with alkaline earth cations. The underlying mechanistic aspects of this type of promotion are not well understood. Here, we study the interaction of Ca2+ with reaction intermediates and products formed during the MTH reaction. Using transient kinetic and spectroscopic tools, we find strong indications that the selectivity differences between Ca/ZSM-5 and HZSM-5 are related to the different local environment inside the pores due to the presence of Ca2+. In particular, Ca/ZSM-5 strongly retains water, hydrocarbons, and oxygenates, which occupy as much as 10% of the micropores during the ongoing MTH reaction. This change in the effective pore geometry affects the formation of hydrocarbon pool components and in this way directs the MTH reaction toward the olefin cycle.
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Affiliation(s)
- Anna Liutkova
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Hao Zhang
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Jérôme F. M. Simons
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Brahim Mezari
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Marta Mirolo
- ESRF, The European Synchrotron, 71 Avenue des Martyrs, CS40220, 38043 Grenoble, Cedex 9, France
| | - Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, St Aubin, B.P. 48, 91192 Gif sur Yvette, France
| | - Emiel J. M. Hensen
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - Nikolay Kosinov
- Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
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14
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Garcia GA, Dontot L, Rapacioli M, Spiegelman F, Bréchignac P, Nahon L, Joblin C. Electronic effects in the dissociative ionisation of pyrene clusters. Phys Chem Chem Phys 2023; 25:4501-4510. [PMID: 36722859 DOI: 10.1039/d2cp05679h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We present a combined experimental and theoretical study on the dissociative ionisation of clusters of pyrene. We measured the experimental appearance energies in the photon energy range 7.2-12.0 eV of the fragments formed from neutral monomer loss for clusters up to the hexamer. The results obtained show a deviation from statistical dissociation. From electronic structure calculations, we suggest that the role of excited states must be considered in the interpretation of experimental results, even in these relatively large systems. Non-statistical effects in the dissociative ionization process of polycyclic aromatic hydrocarbon (PAH) clusters may have an impact on the assessment of mechanisms determining the stability of these clusters in astrophysical environments.
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Affiliation(s)
- Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Départamentale 128, 91190 Saint Aubin, France.
| | - Léo Dontot
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse III - Paul Sabatier, CNRS, CNES, 9 avenue du Colonel Roche, BP 44346, F-31028 Toulouse, France.,Laboratoire de Chimie et Physique Quantiques, FERMI, Université de Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Mathias Rapacioli
- Laboratoire de Chimie et Physique Quantiques, FERMI, Université de Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Fernand Spiegelman
- Laboratoire de Chimie et Physique Quantiques, FERMI, Université de Toulouse III - Paul Sabatier, CNRS, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Philippe Bréchignac
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Départamentale 128, 91190 Saint Aubin, France.
| | - Christine Joblin
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse III - Paul Sabatier, CNRS, CNES, 9 avenue du Colonel Roche, BP 44346, F-31028 Toulouse, France
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15
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Chen NL, Gans B, Hartweg S, Garcia GA, Boyé-Péronne S, Loison JC. Unravelling the electronic structure of the silicon dimer using threshold photoelectron spectroscopy. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2140721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ning L. Chen
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay, France
| | - Bérenger Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay, France
| | | | | | - Séverine Boyé-Péronne
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay, France
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16
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Genossar N, Changala PB, Gans B, Loison JC, Hartweg S, Martin-Drumel MA, Garcia GA, Stanton JF, Ruscic B, Baraban JH. Ring-Opening Dynamics of the Cyclopropyl Radical and Cation: the Transition State Nature of the Cyclopropyl Cation. J Am Chem Soc 2022; 144:18518-18525. [PMID: 36174230 DOI: 10.1021/jacs.2c07740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We provide compelling experimental and theoretical evidence for the transition state nature of the cyclopropyl cation. Synchrotron photoionization spectroscopy employing coincidence techniques together with a novel simulation based on high-accuracy ab initio calculations reveal that the cation is unstable via its allowed disrotatory ring-opening path. The ring strains of the cation and the radical are similar, but both ring opening paths for the radical are forbidden when the full electronic symmetries are considered. These findings are discussed in light of the early predictions by Longuet-Higgins alongside Woodward and Hoffman; we also propose a simple phase space explanation for the appearance of the cyclopropyl photoionization spectrum. The results of this work allow the refinement of the cyclopropane C-H bond dissociation energy, in addition to the cyclopropyl radical and cation cyclization energies, via the Active Thermochemical Tables approach.
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Affiliation(s)
- Nadav Genossar
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel.,Israel Atomic Energy Commission, P.O. Box 7061, Tel Aviv 61070, Israel
| | - P Bryan Changala
- Center for Astrophysics─Harvard & Smithsonian, Cambridge, Massachusetts 02138, United States
| | - Bérenger Gans
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d'Orsay, Orsay 91405, France
| | | | - Sebastian Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, Gif sur Yvette F-91192, France
| | | | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, Gif sur Yvette F-91192, France
| | - John F Stanton
- Quantum Theory Project, Departments of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Branko Ruscic
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Joshua H Baraban
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva 8410501, Israel
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17
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Bourgalais J, Carstensen HH, Herbinet O, Garcia GA, Arnoux P, Tran LS, Vanhove G, Nahon L, Hochlaf M, Battin-Leclerc F. Product Identification in the Low-Temperature Oxidation of Cyclohexane Using a Jet-Stirred Reactor in Combination with SVUV-PEPICO Analysis and Theoretical Quantum Calculations. J Phys Chem A 2022; 126:5784-5799. [PMID: 35998573 DOI: 10.1021/acs.jpca.2c04490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclohexane oxidation chemistry was investigated using a near-atmospheric pressure jet-stirred reactor at T = 570 K and equivalence ratio ϕ = 0.8. Numerous intermediates including hydroperoxides and highly oxygenated molecules were detected using synchrotron vacuum ultraviolet photoelectron photoion coincidence spectroscopy. Supported by high-level quantum calculations, the analysis of photoelectron spectra allowed the firm identification of molecular species formed during the oxidation of cyclohexane. Besides, this work validates recently published gas chromatography and synchrotron vacuum ultraviolet photoionization mass spectrometry data. Unambiguous detection of characteristic hydroperoxides (e.g., γ-ketohydroperoxides) and their respective decomposition products provides support for the conventional O2 addition channels up to the third addition and their relative contribution to the cyclohexane oxidation. The results were also compared with the predictions of a recently proposed new detailed kinetic model of cyclohexane oxidation. Most of the predictions are in line with the current experimental findings, highlighting the robustness of the kinetic model. However, the analysis of the recorded slow photoelectron spectra indicating the possible presence of C5 species in the kinetic model provides hints that the substituted cyclopentyl radicals from cyclohexyl ring opening might play a minor role in cyclohexane oxidation. Potentially important missing reactions are also discussed.
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Affiliation(s)
| | - Hans-Heinrich Carstensen
- Thermochemical Processes Group (GPT), Department of Chemical and Environmental Engineering, Engineering and Architecture School, University of Zaragoza, C. Maria de Luna, 50018 Zaragoza, Spain.,Fundacion Agencia Aragonesa para la Investigacion y el Desarrollo (ARAID), Av. de Ranillas, 50018 Zagaroza, Spain
| | | | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | | | - Luc-Sy Tran
- Université Lille, CNRS, UMR 8522─PC2A─Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Guillaume Vanhove
- Université Lille, CNRS, UMR 8522─PC2A─Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, F-91192 Gif-sur-Yvette Cedex, France
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes, F-77454 Champs-sur-Marne, France
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18
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Matthíasson K, Kvaran Á, Garcia GA, Weidner P, Sztáray B. Coincidence ion pair production (cipp) spectroscopy of diiodine. Phys Chem Chem Phys 2022; 24:17569-17576. [PMID: 35822946 DOI: 10.1039/d2cp01684b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coincidence ion pair production (I+ + I-) (cipp) spectra of I2 were recorded in a double imaging coincidence experiment in the one-photon excitation region of 71 600-74 000 cm-1. The I+ + I- coincidence signal shows vibrational band head structure corresponding to iodine molecule Rydberg states crossing over to ion-pair (I+I-) potential curves above the dissociation limit. The band origin (ν0), vibrational wavenumber (ωe) and anharmonicity constants (ωexe) were determined for the identified Rydberg states. The analysis revealed a number of previously unidentified states and a reassignment of others following a discrepancy in previous assignments. Since the ion pair production threshold is well established, the electric field-dependent spectral intensities were used to derive the cutoff energy in the transitions to the rotational levels of the 7pσ(1/2) (v' = 3) state.
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Affiliation(s)
| | - Ágúst Kvaran
- Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland.
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St, Aubin BP 48, 91192 Gif sur Yvette, France
| | - Peter Weidner
- Department of Chemistry, University of the Pacific, Stockton, CA-95211, USA.
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, CA-95211, USA.
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19
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Chen NL, Gans B, Hartweg S, Garcia GA, Boyé-Péronne S, Loison JC. Photoionization spectroscopy of the SiH free radical in the vacuum-ultraviolet range. J Chem Phys 2022; 157:014303. [DOI: 10.1063/5.0094863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The first measurement of the photoelectron spectrum of the silylidyne free radical, SiH, is reported between 7and 10.5 eV. Two main photoionizing transitions involving the neutral ground state, X+ 1Σ+ ← X 2Π, and a+ 3Π← X 2Π, are assigned using ab initio calculations. The corresponding adiabatic ionization energies are derived,IEad(X+ 1Σ+) = 7.934(5) eV and IEad(a+ 3Π) = 10.205(5) eV, in good agreement with our calculated values andthe previous determination by Berkowitz et al. [Berkowitz et al., J. Chem. Phys., 1987, 86, 1235] from a photoion-ization mass spectrometric study. The photoion yield of SiH recorded in this work exhibits a dense autoionizationlandscape similar to that observed in the case of the CH free radical [Gans et al. J. Chem. Phys., 2016, 144, 204307
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Affiliation(s)
| | - Bérenger Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS Délégation Ile-de-France Sud, France
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20
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Bourgalais J, Jiang Z, Bloino J, Herbinet O, Carstensen HH, Garcia GA, Arnoux P, Tran LS, Vanhove G, Nahon L, Battin-Leclerc F, Hochlaf M. Accounting for molecular flexibility in photoionization: case of tert-butyl hydroperoxide. Phys Chem Chem Phys 2022; 24:10826-10837. [PMID: 35485277 DOI: 10.1039/d2cp00929c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
tert-Butyl hydroperoxide (tBuOOH) is a common intermediate in the oxidation of organic compounds that needs to be accurately quantified in complex gas mixtures for the development of chemical kinetic models of low temperature combustion. This work presents a combined theoretical and experimental investigation on the synchrotron-based VUV single photon ionization of gas-phase tBuOOH in the 9.0 - 11.0 eV energy range, including dissociative ionization processes. Computations consist of the determination of the structures, vibrational frequencies and the energetics of neutral and ionic tBuOOH. The Franck-Condon spectrum for the tBuOOH+ (X+) + e- ← tBuOOH (X) + hν transition is computed, where special treatment is undertaken because of the flexibility of tBuOOH, in particular regarding the OOH group. Through comparison of the experimental mass-selected threshold photoelectron spectra with explicitly correlated coupled cluster calculations and Franck-Condon simulations that account for the flexibility of the molecule, an estimation of the ionization energy is given. The appearance energy of the only fragment observed within the above-mentioned energy range, identified as the tert-butyl C4H9+, is also reported. Finally, the signal branching ratio between the parent and the fragment ions is provided as a function of photon energy, essential to quantify tBuOOH in gas-phase oxidation/combustion experiments via advanced mass spectrometry techniques.
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Affiliation(s)
| | | | - Julien Bloino
- SMART Laboratory, Scuola Normale Superiore, Pisa, Italy
| | | | - Hans-Heinrich Carstensen
- Thermochemical Processes Group (GPT), Department of Chemical and Environmental Engineering, Engineering and Architecture School, University of Zaragoza, Spain.,Fundacion Agencia Aragonesa para la Investigacion y el Desarrollo (ARAID), Zagaroza, Spain
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, 91192 Gif-sur-Yvette Cedex, France
| | | | - Luc-Sy Tran
- PC2A, Université de Lille, CNRS, Avenue Mendeleiev, 59650 Villeneuve-d'Ascq, France
| | - Guillaume Vanhove
- PC2A, Université de Lille, CNRS, Avenue Mendeleiev, 59650 Villeneuve-d'Ascq, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin-BP 48, 91192 Gif-sur-Yvette Cedex, France
| | | | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs sur Marne, France.
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21
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Dupont J, Lepère V, Zehnacker A, Hartweg S, Garcia GA, Nahon L. Photoelectron Circular Dichroism as a Signature of Subtle Conformational Changes: The Case of Ring Inversion in 1-Indanol. J Phys Chem Lett 2022; 13:2313-2320. [PMID: 35245057 DOI: 10.1021/acs.jpclett.2c00074] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Chirality plays a fundamental role in the molecular recognition processes. Molecular flexibility is also crucial in molecular recognition, allowing the interacting molecules to adjust their structures and hence optimize the interaction. Methods probing simultaneously chirality and molecular conformation are therefore crucially needed. Taking advantage of a possible control in the gas phase of the conformational distribution between the equatorial and axial conformers resulting from a ring inversion in jet-cooled 1-indanol, we demonstrate here the sensitivity of valence-shell photoelectron circular dichroism (PECD) to both chirality and subtle conformational changes, in a case where the photoelectron spectra of the two conformers are identical. For the highest occupied orbital, we observe a dramatic inversion of the PECD-induced photoelectron asymmetries, while the photoionization cross-section and usual anisotropy (β) parameter are completely insensitive to conformational isomerism. Such a sensitivity is a major asset for the ongoing developments of PECD-based techniques as a sensitive chiral (bio)chemical analytical tool in the gas phase.
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Affiliation(s)
- Jennifer Dupont
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Valéria Lepère
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay, F-91405 Orsay, France
| | - Sebastian Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
| | - Gustavo A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
| | - Laurent Nahon
- Synchrotron Soleil, L'Orme des Merisiers, St. Aubin BP48, F-91192 Gif sur Yvette, France
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22
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Zhang C, Lin X, Tang X, Fittschen C, Hartweg S, Garcia GA, Long B, Zhang W, Nahon L. Vacuum ultraviolet photochemistry of sulfuric acid vapor: a combined experimental and theoretical study. Phys Chem Chem Phys 2022; 24:2015-2021. [PMID: 35018921 DOI: 10.1039/d1cp05237c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We present a vacuum ultraviolet (VUV) photoionization study of the gas-phase sulfuric acid (H2SO4) molecule in the 11-14 eV energy range by using the method of synchrotron radiation-based double imaging photoelectron photoion coincidence (i2PEPICO) spectroscopy complemented with accurate theoretical calculations. The slow photoelectron spectrum (SPES) of H2SO4 has been acquired and the three electronic states of H2SO4+, X2A, A2A and B2A have been populated and assigned. The adiabatic ionization energy of the H2SO4 molecule towards the X2A cationic ground state is measured at 11.684 ± 0.006 eV, in accordance with high-level calculated findings. With increasing photon energies, the H2SO4+ cation dissociates into HSO3+ and OH fragments and their adiabatic appearance energy is measured at 13.498 ± 0.007 eV. Then, the enthalpies of formation for the species involved in the photoionization and dissociative photoionization have been determined through a thermochemical cycle.
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Affiliation(s)
- Cuihong Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China. .,Graduate School, University of Science and Technology of China, Hefei, 230026 Anhui, China.,University Lille, CNRS, UMR 8522, PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Christa Fittschen
- University Lille, CNRS, UMR 8522, PC2A - Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Sebastian Hartweg
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette, France.
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette, France.
| | - Bo Long
- School of Materials Science and Engineering, Guizhou Minzu University, Guiyang, 550025 Guizhou, China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China.
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette, France.
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23
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Darquié B, Saleh N, Tokunaga SK, Srebro-Hooper M, Ponzi A, Autschbach J, Decleva P, Garcia GA, Crassous J, Nahon L. Valence-shell photoelectron circular dichroism of ruthenium(III)-tris-(acetylacetonato) gas-phase enantiomers. Phys Chem Chem Phys 2021; 23:24140-24153. [PMID: 34666343 DOI: 10.1039/d1cp02921e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chiral transition-metal complexes are of interest in many fields ranging from asymmetric catalysis and molecular materials science to optoelectronic applications or fundamental physics including parity violation effects. We present here a combined theoretical and experimental investigation of gas-phase valence-shell photoelectron circular dichroism (PECD) on the challenging open-shell ruthenium(III)-tris-(acetylacetonato) complex, Ru(acac)3. Enantiomerically pure Δ- or Λ-Ru(acac)3, characterized by electronic circular dichroism (ECD), were vaporized and adiabatically expanded to produce a supersonic beam and photoionized by circularly-polarized VUV light from the DESIRS beamline at Synchrotron SOLEIL. Photoelectron spectroscopy (PES) and PECD experiments were conducted using a double imaging electron/ion coincidence spectrometer, and compared to density functional theory (DFT) and time-dependent DFT (TDDFT) calculations. The open-shell character of Ru(acac)3, which is not taken into account in our DFT approach, is expected to give rise to a wide multiplet structure, which is not resolved in our PES signals but whose presence might be inferred from the additional striking features observed in the PECD curves. Nevertheless, the DFT-based assignment of the electronic bands leads to the characterisation of the ionized orbitals. In line with other recent works, the results confirm that PECD persists independently on the localization and/or on the achiral or chiral nature of the initial orbital, but is rather a probe of the molecular potential as a whole. Overall, the measured PECD signals on Ru(acac)3, a system exhibiting D3 propeller-type chirality, are of similar magnitude compared to those on asymmetric-carbon-based chiral organic molecules which constitute the vast majority of species investigated so far, thus suggesting that PECD is a universal mechanism, inherent to any type of chirality.
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Affiliation(s)
- Benoît Darquié
- Laboratoire de Physique des Lasers, Université Sorbonne Paris Nord, CNRS, Villetaneuse, France.
| | - Nidal Saleh
- Univ Rennes CNRS, ISCR-UMR 6226 ScanMat - UMS 2001, 35000 Rennes, France.
| | - Sean K Tokunaga
- Laboratoire de Physique des Lasers, Université Sorbonne Paris Nord, CNRS, Villetaneuse, France.
| | - Monika Srebro-Hooper
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland.
| | - Aurora Ponzi
- CNR IOM and Dipartimento di Scienze Chimiche e Farmaceutiche, Universita' di Trieste, I-34127 Trieste, Italy.
| | - Jochen Autschbach
- Department of Chemistry, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Piero Decleva
- CNR IOM and Dipartimento di Scienze Chimiche e Farmaceutiche, Universita' di Trieste, I-34127 Trieste, Italy.
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France.
| | - Jeanne Crassous
- Univ Rennes CNRS, ISCR-UMR 6226 ScanMat - UMS 2001, 35000 Rennes, France.
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France.
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Laamiri K, Garcia GA, Nahon L, Ben Houria A, Feifel R, Hochlaf M. Threshold photoelectron spectroscopy of 9-methyladenine: theory and experiment. Phys Chem Chem Phys 2021; 24:3523-3531. [PMID: 34676858 DOI: 10.1039/d1cp03729c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
We present a combined experimental and theoretical study of single-photon ionization of 9-methyladenine (9MA) in the gas phase. In addition to tautomerism, several rotamers due to the rotation of the methyl group may exist. Computations show, however, that solely one rotamer contributes because of low population in the molecular beam and/or unfavorable Franck-Condon factors upon ionization. Experimentally, we used VUV radiation available at the DESIRS beamline of the synchrotron radiation facility SOLEIL to record the threshold photoelectron spectrum of this molecule between 8 and 11 eV. This spectrum consists of a well-resolved band assigned mainly to vibronic levels of the D0 cationic state, plus a contribution from the D1 state, and two large bands corresponding to the D1, D2 and D3 electronically excited states. The adiabatic ionization energy of 9MA is measured at 8.097 ± 0.005 eV in close agreement with the computed value using the explicitly correlated coupled cluster approach including core valence, scalar relativistic and zero-point vibrational energy corrections. This work sheds light on the complex pattern of the lowest doublet electronic states of 9MA+. The comparison to canonical adenine reveals that methylation induces further electronic structure complication that may be important to understand the effects of ionizing radiation and the charge distribution in these biological entities at different time scales.
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Affiliation(s)
- K Laamiri
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs-sur-Marne, France. .,Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - G A Garcia
- Synchrotron SOLEIL, L'orme des Merisiers, Saint-Aubin - BP 48 - 91192 Gif-sur-Yvette Cedex, France
| | - L Nahon
- Synchrotron SOLEIL, L'orme des Merisiers, Saint-Aubin - BP 48 - 91192 Gif-sur-Yvette Cedex, France
| | - A Ben Houria
- Laboratoire de Spectroscopie Atomique, Moléculaire et Applications - LSAMA, Université de Tunis El Manar, Tunis, Tunisia
| | - R Feifel
- University of Gothenburg, Department of Physics, 412 58 Gothenburg, Sweden
| | - M Hochlaf
- Université Gustave Eiffel, COSYS/LISIS, 5 Bd Descartes 77454, Champs-sur-Marne, France.
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Abstract
Hydrogen bonds and proton transfer reactions can be considered as being at the very heart of aqueous chemistry and of utmost importance for many processes of biological relevance. Nevertheless, these processes are not yet well understood, even in seemingly simple model systems like small water clusters. We present a study of the photoelectron spectrum of the water dimer, revealing previously unresolved vibrational structure with 10-30 meV (80-242 cm-1) typical splitting, in disagreement with a previous theoretical photoionization study predicting an apparent main vibrational progression with an ∼130 meV spacing [Kamarchik et al.; J. Chem. Phys. 2010, 132, 194311]. The observed vibrational structure and its deviation from the theoretical prediction is discussed in terms of known difficulties with calculations of strongly coupled anharmonic systems involving large amplitude motions. Potential contributions of the nonzero vibrational energy of the neutral water dimer at a finite experimental internal temperature are addressed. The internal temperature is estimated from the breakdown diagram associated with the dissociative ionization of the water dimer to be around to 130 K. This analysis also provides two additional, independently measured values for the 0 K appearance energy of the hydronium ion (H3O+) from dissociative ionization of the water dimer.
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Affiliation(s)
- Sebastian Hartweg
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
| | - Gustavo A Garcia
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
| | - Laurent Nahon
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
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Hadidi R, Božanić, DK, Ganjitabar H, Garcia GA, Powis I, Nahon L. Conformer-dependent vacuum ultraviolet photodynamics and chiral asymmetries in pure enantiomers of gas phase proline. Commun Chem 2021; 4:72. [PMID: 36697576 PMCID: PMC9814706 DOI: 10.1038/s42004-021-00508-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 04/15/2021] [Indexed: 02/03/2023] Open
Abstract
Proline is a unique amino-acid, with a secondary amine fixed within a pyrrolidine ring providing specific structural properties to proline-rich biopolymers. Gas-phase proline possesses four main H-bond stabilized conformers differing by the ring puckering and carboxylic acid orientation. The latter defines two classes of conformation, whose large ionization energy difference allows a unique conformer-class tagging via electron spectroscopy. Photoelectron circular dichroism (PECD) is an intense chiroptical effect sensitive to molecular structures, hence theorized to be highly conformation-dependent. Here, we present experimental evidence of an intense and striking conformer-specific PECD, measured in the vacuum ultraviolet (VUV) photoionization of proline, as well as a conformer-dependent cation fragmentation behavior. This finding, combined with theoretical modeling, allows a refinement of the conformational landscape and energetic ordering, that proves inaccessible to current molecular electronic structure calculations. Additionally, astrochemical implications regarding a possible link of PECD to the origin of life's homochirality are considered in terms of plausible temperature constraints.
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Affiliation(s)
- Rim Hadidi
- grid.426328.9Synchrotron SOLEIL, l’Orme des Merisiers, Gif sur Yvette Cedex, France
| | - Dušan K. Božanić,
- grid.426328.9Synchrotron SOLEIL, l’Orme des Merisiers, Gif sur Yvette Cedex, France ,grid.7149.b0000 0001 2166 9385Present Address: Department of Radiation Chemistry and Physics, “VINČA” Institute of Nuclear Sciences—National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Hassan Ganjitabar
- grid.4563.40000 0004 1936 8868School of Chemistry, The University of Nottingham, University Park, Nottingham, UK
| | - Gustavo A. Garcia
- grid.426328.9Synchrotron SOLEIL, l’Orme des Merisiers, Gif sur Yvette Cedex, France
| | - Ivan Powis
- grid.4563.40000 0004 1936 8868School of Chemistry, The University of Nottingham, University Park, Nottingham, UK
| | - Laurent Nahon
- grid.426328.9Synchrotron SOLEIL, l’Orme des Merisiers, Gif sur Yvette Cedex, France
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Matthíasson K, Kvaran Á, Garcia GA, Weidner P, Sztáray B. Resolving the F 2 bond energy discrepancy using coincidence ion pair production (cipp) spectroscopy. Phys Chem Chem Phys 2021; 23:8292-8299. [PMID: 33875993 DOI: 10.1039/d1cp00140j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coincidence ion pair production (cipp) spectra of F2 were recorded on the DELICIOUS III coincidence spectrometer in the one-photon excitation region of 125 975-126 210 cm-1. The F+ + F- signal shows a rotational band head structure, corresponding to F2 Rydberg states crossing over to the ion pair production surface. Spectral simulation and quantum defect analysis allowed the characterization of five new molecular Rydberg states (F2**): one Π and four Σ states. The lowest-energy Rydberg state spectrum observed (T0 = 125 999 cm-1) lacked some of the predicted rotational structure, which allowed an accurate determination of the ion pair production threshold of 15.62294± 0.00043 eV. Using the well-known atomic fluorine ionization energy and electron affinity, this number leads to a ground state F-F dissociation energy of 1.60129± 0.00044 eV. Photoelectron photoion coincidence (PEPICO) experiments were also carried out on F2 and the dissociative photoionization threshold to F+ + F was determined as 19.0242 ± 0.0006 eV. Using the atomic fluorine ionization energy, this can be converted to an F2 dissociation energy of 1.60132± 0.00062 eV, further confirming the cipp-derived value above. Because the two experiments were independently energy-calibrated, they can be averaged to 1.60130± 0.00036 eV and this value can be used to derive the fluorine atom's 0 K heat of formation as 77.251± 0.017 kJ mol-1. This latter is in excellent agreement with the latest Active Thermochemical Table (ATcT) value but improves its accuracy by almost a factor of three.
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Harper OJ, Gans B, Loison JC, Garcia GA, Hrodmarsson HR, Boyé-Péronne S. Photoionization Cross Section of the NH 2 Free Radical in the 11.1-15.7 eV Energy Range. J Phys Chem A 2021; 125:2764-2769. [PMID: 33783226 DOI: 10.1021/acs.jpca.1c01876] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The NH2 radical is a key component in many astrophysical environments, both in its neutral and cationic forms, being involved in the formation of complex N-bearing species. To gain insight into the photochemical processes into which it operates and to model accurately the ensuing chemical networks, the knowledge of its photoionization efficiency is required, but no quantitative determination has been carried out so far. Combining a flow-tube H-abstraction radical source, a double imaging photoelectron-photoion spectrometer, and a vacuum-ultraviolet synchrotron excitation, the absolute photoionization cross section of the amino radical has been measured in the present work for the first time at two photon energies: σionNH2(12.7 eV) = 7.8 ± 2.2 Mb and σionNH2(13.2 eV) = 7.8 ± 2.0 Mb. These values have been employed to scale the total ion yield previously recorded by Gibson et al. ( J. Chem. Phys. 1985, 83, 4319-4328). The resulting cross section curve spanning the 11.1-15.7 eV energy range will help in refining the current astrophysical models.
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Affiliation(s)
- Oliver J Harper
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Bérenger Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, 91405, Orsay, France
| | - Jean-Christophe Loison
- Institut des Sciences Moléculaires, UMR 5255 CNRS-Université de Bordeaux, Bât. A12, 351 cours de la Libération, F-33405 Talence Cedex, France
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France
| | - Helgi R Hrodmarsson
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France
| | - Séverine Boyé-Péronne
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, 91405, Orsay, France
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Hartweg S, Garcia GA, Božanić DK, Nahon L. Condensation Effects on Electron Chiral Asymmetries in the Photoionization of Serine: From Free Molecules to Nanoparticles. J Phys Chem Lett 2021; 12:2385-2393. [PMID: 33660503 DOI: 10.1021/acs.jpclett.1c00258] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Structural changes at the molecular level, occurring at the onset of condensation, can be probed by angle-resolved valence photoelectron spectroscopy, which is inherently sensitive to the electronic structure. For larger condensed systems like aerosol particles, the observation of intrinsic angular anisotropies in photoemission (β parameters) is challenging due to the strong reduction of their magnitude by electron transport effects. Here, we use a less common, more sensitive observable in the form of the chiral asymmetry parameter to perform a comparative study of the VUV photoelectron spectroscopy and photoelectron circular dichroism (PECD) between pure gas phase enantiomers of the amino acid serine and their corresponding homochiral nanoparticles. We observe a relatively large (1%) and strongly kinetic energy-dependent asymmetry, discussed in terms of the emergence of local order and conformational changes potentially counterbalancing the loss of angular information due to electron transport scattering. This demonstrates the potential of PECD as a sensitive probe of the condensation effects from the gas phase to bulk-like chiral aerosol particles surpassing the potential of conventional photoemission observables such as β parameters.
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Affiliation(s)
- Sebastian Hartweg
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Cedex, Gif sur Yvette, France
| | - Gustavo A Garcia
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Cedex, Gif sur Yvette, France
| | - Dušan K Božanić
- Department of Radiation Chemistry and Physics, "VINČA" Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, 11001 Belgrade, Serbia
| | - Laurent Nahon
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Cedex, Gif sur Yvette, France
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30
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Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei, 230031 Anhui, China
| | - Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin BP 48, 91192 Gif sur Yvette, France
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Durif O, Capron M, Messinger JP, Benidar A, Biennier L, Bourgalais J, Canosa A, Courbe J, Garcia GA, Gil JF, Nahon L, Okumura M, Rutkowski L, Sims IR, Thiévin J, Le Picard SD. A new instrument for kinetics and branching ratio studies of gas phase collisional processes at very low temperatures. Rev Sci Instrum 2021; 92:014102. [PMID: 33514236 DOI: 10.1063/5.0029991] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
A new instrument dedicated to the kinetic study of low-temperature gas phase neutral-neutral reactions, including clustering processes, is presented. It combines a supersonic flow reactor with vacuum ultra-violet synchrotron photoionization time-of-flight mass spectrometry. A photoion-photoelectron coincidence detection scheme has been adopted to optimize the particle counting efficiency. The characteristics of the instrument are detailed along with its capabilities illustrated through a few results obtained at low temperatures (<100 K) including a photoionization spectrum of n-butane, the detection of formic acid dimer formation, and the observation of diacetylene molecules formed by the reaction between the C2H radical and C2H2.
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Affiliation(s)
- O Durif
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - M Capron
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J P Messinger
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - A Benidar
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - L Biennier
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J Bourgalais
- LATMOS/IPSL, UVSQ, Université Paris-Saclay, UPMC, Univ Paris 06, CNRS, 78280 Guyancourt, France
| | - A Canosa
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J Courbe
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - G A Garcia
- Synchrotron SOLEIL, L'orme des Merisiers, BP48 St Aubin, 91192 Gif Sur Yvette Cedex, France
| | - J F Gil
- Synchrotron SOLEIL, L'orme des Merisiers, BP48 St Aubin, 91192 Gif Sur Yvette Cedex, France
| | - L Nahon
- Synchrotron SOLEIL, L'orme des Merisiers, BP48 St Aubin, 91192 Gif Sur Yvette Cedex, France
| | - M Okumura
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA
| | - L Rutkowski
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - I R Sims
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - J Thiévin
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
| | - S D Le Picard
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes) - UMR 6251, F-35000 Rennes, France
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Singh DP, De Oliveira N, Garcia GA, Vredenborg A, Powis I. Experimental and Theoretical Investigation of the 3sp(d) Rydberg States of Fenchone by Polarized Laser Resonance-Enhanced-Multiphoton-Ionization and Fourier Transform VUV Absorption Spectroscopy. Chemphyschem 2020; 21:2468-2483. [PMID: 32893958 DOI: 10.1002/cphc.202000365] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/04/2020] [Indexed: 11/08/2022]
Abstract
The VUV absorption spectrum of fenchone is re-examined using synchrotron radiation Fourier transform spectrometry, revealing new vibrational structure. Picosecond laser (2+1) resonance enhanced multiphoton ionization (REMPI) spectroscopy complements this, providing an alternative view of the 3spd Rydberg excitation region. These spectra display broadly similar appearance, with minor differences that are largely explained by referring to calculated one- and two-photon electronic excitation cross-sections. Both show good agreement with Franck-Condon simulations of the relevant vibrational structures. Parent ion REMPI ionization yields with both femtosecond and picosecond excitation laser pulses are studied as a function of laser polarization and intensity, the latter providing insight into the relative two-photon excitation and one-photon ionization rates. The experimental circular-linear dichroism observed in the parent ion yields varies strongly between the 3s and 3p Rydberg states, in good overall agreement with the calculated two-photon excitation circular-linear dichroism, while corroborating other evidence that the 3pz sub-state plays no more than a very minor role in the (2+1) REMPI spectrum. Vibrationally resolved photoelectron spectra are recorded with picosecond pulse duration (2+1) REMPI at selected intermediate vibrational excitations. The 3s intermediate state displays a very strong Δv=0 propensity on ionization, but the 3p intermediate evidences more complex vibronic dynamics, and we infer some 3p→3s internal conversion prior to ionization.
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Affiliation(s)
- Dhirendra P Singh
- School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, U.K
| | - Nelson De Oliveira
- Synchrotron SOLEIL, l'Orme des Merisiers, 91192 Cedex, Saint-Aubin BP 48, Gif-sur-Yvette, France
| | - Gustavo A Garcia
- Synchrotron SOLEIL, l'Orme des Merisiers, 91192 Cedex, Saint-Aubin BP 48, Gif-sur-Yvette, France
| | - Arno Vredenborg
- Institute for Molecules and Materials, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ, Nijmegen, Netherlands
- MassSpecpecD BV, Langenkampweg 101, 7522 LL, Enschede, Netherlands
| | - Ivan Powis
- School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, U.K
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33
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Garcia GA, Loison JC, Holzmeier F, Gans B, Alcaraz C, Nahon L, Wu X, Zhou X, Bodi A, Hemberger P. Characterisation of the first electronically excited state of protonated acetylene C2H3+ by coincident imaging photoelectron spectroscopy. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1825851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - Jean-Christophe Loison
- Institut des Sciences Moléculaires, UMR 5255 CNRS - Université de Bordeaux, Cedex, France
| | - Fabian Holzmeier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Wüzburg, Germany
| | - Bérenger Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay, France
| | - Christian Alcaraz
- Institut de Chimie Physique, CNRS, Université Paris-Saclay, Orsay, France
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, Cedex, France
| | - Xiangkun Wu
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Peoples Republic of China
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Xiaoguo Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei, Peoples Republic of China
| | - Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, Villigen, Switzerland
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Tang X, Lin X, Garcia GA, Loison JC, Fittschen C, Röder A, Schleier D, Gu X, Zhang W, Nahon L. Threshold photoelectron spectroscopy of the HO 2 radical. J Chem Phys 2020; 153:124306. [PMID: 33003730 DOI: 10.1063/5.0022410] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report a synchrotron radiation vacuum ultraviolet photoionization study of the hydroperoxyl radical (HO2), a key reaction intermediate in combustion and atmospheric chemistry as well as astrochemistry, using double imaging photoelectron photoion coincidence spectroscopy. The HO2 radical is formed in a microwave discharge flow tube reactor through a set of reactions initiated by F atoms in a CH4/O2/He gas mixture. The high-resolution threshold photoelectron spectrum of HO2 in the 11 eV-12 eV energy range is acquired without interferences from other species and assigned with the aid of theoretically calculated adiabatic ionization energies (AIEs) and Franck-Condon factors. The three vibrational modes of the radical cation HO2 +, the H-O stretch, the H-O-O bend, and the O-O stretch, have been identified, and their individual frequencies are measured. In addition, the AIEs of the X3A″ ground state and the a1A' first excited electronic state of HO2 + are experimentally determined at 11.359 ± 0.003 eV and 11.639 ± 0.005 eV, respectively, in agreement with high-level theoretically computed results. Furthermore, the former AIE value provides validation of thermochemical networks used to extract the enthalpy of formation of the HO2 radical.
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Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
| | - Jean-Christophe Loison
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Liber̀ation, 33400 Talence, France
| | - Christa Fittschen
- University Lille, CNRS, UMR 8522, PC2A-Physicochimie des Processus de Combustion et de l'Atmosphère, F-59000 Lille, France
| | - Anja Röder
- Institute of Physical and Theoretical Chemistry, University of Wurzburg, Am Hubland, D-97074 Wurzburg, Germany
| | - Domenik Schleier
- Institute of Physical and Theoretical Chemistry, University of Wurzburg, Am Hubland, D-97074 Wurzburg, Germany
| | - Xuejun Gu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Laurent Nahon
- Synchrotron SOLEIL, L'Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
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35
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Harper OJ, Coudert LH, Loison JC, Gans B, Douin S, Garcia GA, Guillemin JC, Boyé-Péronne S. Quasi-symmetry effects in the threshold photoelectron spectrum of methyl isocyanate. J Chem Phys 2020; 153:074308. [DOI: 10.1063/5.0017753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Oliver J. Harper
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Laurent H. Coudert
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Jean-Christophe Loison
- Institut des Sciences Moléculaires, UMR 5255 CNRS-Université de Bordeaux, Bât. A12, 351 Cours de la Libération, F-33405 Talence Cedex, France
| | - Bérenger Gans
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Stéphane Douin
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
| | - Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP 48, Gif sur Yvette, France
| | - Jean-Claude Guillemin
- Univ. Rennes, Ecole Nationale Supérieure de Chimie de Rennes, CNRS, ISCR-UMR6226, F-35000 Rennes, France
| | - Séverine Boyé-Péronne
- Université Paris-Saclay, CNRS, Institut des Sciences Moléculaires d’Orsay, 91405 Orsay, France
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Abstract
Single-photon, photoelectron-photoion coincidence spectroscopy is used to record the mass-selected ion spectra and slow photoelectron spectra of C4H5 radicals produced by the abstraction of hydrogen atoms from three C4H6 precursors by fluorine atoms generated by a microwave discharge. Three different C4H5 isomers are identified, with the relative abundances depending on the nature of the precursor (1-butyne, 1,2-butadiene, and 1,3-butadiene). The results are compared with our previous work using 2-butyne as a precursor [Hrodmarsson, H. R. J. Phys. Chem. A 2019, 123, 1521-1528]. The slow photoelectron spectra provide new information on the three radical isomers that is in good agreement with previous experimental and theoretical results [Lang, M. J. Phys. Chem. A 2015, 119, 3995-4000; Hansen, N. J. Phys. Chem. A 2006, 110, 3670-3678]. The energy scans of the C4H5 photoionization signal are recorded with substantially better resolution and signal-to-noise ratio than those in earlier work, allowing the observation of autoionizing resonances based on excited states of the C4H5 cation. Photoelectron images recorded at several energies are also reported, providing insight into the decay processes of these excited states. Finally, in contrast to the earlier work using 2-butyne as a precursor, where H-atom abstraction was the only observed process, F- and H-atom additions to the present precursors are also observed through the detection of C4H6F, C4H5F, and C4H7.
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Affiliation(s)
- S Hartweg
- Synchrotron Soleil, L'Orme des Merisiers, Gif-sur-Yvette F-91192, France
| | - J-C Loison
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, Talence 33400, France
| | - S Boyé-Péronne
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay F-91405, France
| | - B Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, Orsay F-91405, France
| | - D M P Holland
- STFC, Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, U.K
| | - G A Garcia
- Synchrotron Soleil, L'Orme des Merisiers, Gif-sur-Yvette F-91192, France
| | - L Nahon
- Synchrotron Soleil, L'Orme des Merisiers, Gif-sur-Yvette F-91192, France
| | - S T Pratt
- Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
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Ganjitabar H, Garcia GA, Nahon L, Powis I. Decoupling vibration and electron energy dependencies in the photoelectron circular dichroism of a terpene, 3-carene. J Chem Phys 2020; 153:034302. [PMID: 32716160 DOI: 10.1063/5.0013448] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A fresh perspective on the interaction of electron and nuclear motions in photon induced dynamical processes can be provided by the coupling of photoelectron angular distributions and cation vibrational states in the photoionization of chiral molecules using circularly polarized radiation. The chiral contributions, manifesting as a forward-backward asymmetry in the photoemission, can be assessed using Photoelectron Circular Dichroism (PECD), which has revealed an enhanced vibrational influence exerted on the outgoing photoelectron. In this paper, we investigate the PECD of a rigid chiral monoterpene, 3-carene, using single-photon vacuum ultraviolet ionization by polarized synchrotron radiation and selecting energies from the ionization threshold up to 19.0 eV. By judicious choice of these photon energies, two factors that influence PECD asymmetry values, electron kinetic energy and ion vibrational level, can be effectively isolated, allowing a clear demonstration of the very marked vibrational effects. A slow photoelectron spectrum is used to examine the vibrational structure of the isolated outermost valence (HOMO) photoelectron band, and peak assignments are made with the aid of a Franck-Condon simulation. Together, these provide an estimate of the adiabatic ionization energy as 8.385 eV. The reported chiral asymmetry from the randomly oriented 3-carene enantiomers reaches a maximum of over 21%. Theoretical PECD calculations, made both for the fixed equilibrium molecular geometry and also modeling selected normal mode vibration effects, are presented to provide further insight.
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Affiliation(s)
- Hassan Ganjitabar
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
| | - Gustavo A Garcia
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
| | - Laurent Nahon
- Synchrotron SOLEIL, l'Orme des Merisiers, Saint Aubin BP 48, 91192 Gif sur Yvette Cedex, France
| | - Ivan Powis
- School of Chemistry, The University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
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Tang X, Lin X, Garcia GA, Loison JC, Fittschen C, Gu X, Zhang W, Nahon L. Threshold photoelectron spectroscopy of the methoxy radical. J Chem Phys 2020; 153:031101. [DOI: 10.1063/5.0016146] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
| | - Jean-Christophe Loison
- Institut des Sciences Moléculaires (ISM), CNRS, Univ. Bordeaux, 351 cours de la Libération, 33400, Talence, France
| | - Christa Fittschen
- University Lille, CNRS, UMR 8522, PC2A – Physicochimie des Processus de Combustion et de l’Atmosphère, F-59000 Lille, France
| | - Xuejun Gu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, HFIPS, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Laurent Nahon
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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40
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Erickson BP, Garcia GA. Evidence-based algorithm for the management of acute traumatic retrobulbar haemorrhage. Br J Oral Maxillofac Surg 2020; 58:1091-1096. [PMID: 32546417 DOI: 10.1016/j.bjoms.2020.05.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 05/19/2020] [Indexed: 11/28/2022]
Abstract
Retrobulbar haemorrhage (RBH) is a potentially blinding consequence of craniofacial trauma, but timely ophthalmic evaluation is difficult to obtain in some settings and clear standards for canthotomy/cantholysis are lacking. We have sought to develop an algorithm to identify vision-threatening traumatic RBH that requires emergent decompression. We retrospectively reviewed 42 consecutive consultations for RBH at a level-one trauma centre. Charts and imaging studies were analysed with attention to mechanism of injury, comorbid trauma, and ophthalmic findings. A total of 22 eyes were observed without intervention, 13 were treated pharmacologically, and seven by emergent canthotomy/cantholysis. No differences in standard trauma metrics were found among these groups. Lid oedema, ecchymosis, chemosis, subconjunctival haemorrhage, and ocular motility also failed to correlate with a need for surgical intervention. "Tight" eyelids (p<0.001), unilateral proptosis (p<0.001), and relative afferent pupillary defect (RAPD; p=0.029), however, all related to a need for canthotomy/cantholysis (Fisher's exact test). Tenting of the globe, which was the only radiographic finding to predict the need for surgery, was seen in just two of the seven cases that required decompression. Many of the traditionally emphasised clinical signs therefore fail to identify cases of RBH that require decompression. Our data support a simple three-factor decision tool. These are: relative proptosis, eyelids that are difficult to open with finger pressure, and presence of an RAPD in the traumatised eye. If all three are noted or if the patient has proptosis and tight lids in the absence of a large preseptal haematoma, he/she is likely to need surgical decompression. Tenting of the globe on computed tomography (CT), while a relatively rare finding, should also alert the physician of the need for intervention.
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Affiliation(s)
- B P Erickson
- Byers Eye Institute, Stanford University, Palo Alto, CA; Stanford University Hospital, Stanford, CA
| | - G A Garcia
- Byers Eye Institute, Stanford University, Palo Alto, CA; Stanford University Hospital, Stanford, CA.
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Garcia GA, Krüger J, Gans B, Falvo C, Coudert LH, Loison JC. Erratum: “Valence shell threshold photoelectron spectroscopy of the CHxCN (x = 0–2) and CNC radicals” [J. Chem. Phys. 147, 013908 (2017)]. J Chem Phys 2020; 152:169903. [DOI: 10.1063/5.0010035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France
| | - Julia Krüger
- Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France
| | - Bérenger Gans
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Cyril Falvo
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Laurent H. Coudert
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France
| | - Jean-Christophe Loison
- Institut des Sciences Moléculaires, UMR 5255 CNRS—Université de Bordeaux, Bât. A12, 351 Cours de la Libération, F-33405 Talence Cedex, France
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42
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Tang X, Gu X, Lin X, Zhang W, Garcia GA, Fittschen C, Loison JC, Voronova K, Sztáray B, Nahon L. Vacuum ultraviolet photodynamics of the methyl peroxy radical studied by double imaging photoelectron photoion coincidences. J Chem Phys 2020; 152:104301. [DOI: 10.1063/5.0002109] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xuejun Gu
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, Anhui, China
- School of Environmental Science and Optoelectronic Technology, University of Science and Technology of China, Hefei 230026, Anhui, China
| | - Gustavo A. Garcia
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
| | - Christa Fittschen
- University Lille, CNRS, UMR 8522, PC2A – Physicochimie des Processus de Combustion et de l’Atmosphère, F-59000 Lille, France
| | - Jean-Christophe Loison
- ISM, Université Bordeaux 1, CNRS, 351 cours de la Libération, 33405 Talence Cedex, France
| | - Krisztina Voronova
- Department of Chemistry, University of Nevada, Reno, Reno, Nevada 89557-0216, USA
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, Stockton, California 95211, USA
| | - Laurent Nahon
- Synchrotron SOLEIL, L’Orme des Merisiers, St. Aubin, BP 48, 91192 Gif sur Yvette, France
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43
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Rudge MVC, Souza FP, Abbade JF, Hallur RLS, Marcondes JPC, Piculo F, Marini G, Vesentini G, Thabane L, Witkin SS, Calderon IMP, Barbosa AMP, Rudge MV, Barbosa AMP, Calderon IMP, Souza FP, Abbade JF, Hallur LSR, Piculo F, Marini G, Vesentini G, Thabane L, Palma MS, Graeff CFO, Arni RK, Herculano RD, Salvadori DF, Mateus S, Dal Pai Silva M, Magalhães CG, Costa RA, Lima SAM, Felisbino SL, Barbosa W, Atallah A, Girão MJB, Di Bella Z, Uchoa SM, Payão S, Hijas A, Berghman B, De Bie R, Sobrevia L, Junginger B, Alves FCB, Rossignoli PS, Prudencio CB, Orlandi MIG, Gonçalves MI, Nunes SK, Catinelli BB, Quiroz S, Sarmento BV, Pinheiro FA, Sartorão CI, Lucas RR, Reyes DRA, Quiroz SBCV, Enriquez EMA, Oliveira RG, Floriano JF, Marcondes JPC, Barneze S, Dangió TD, Pascon T, Rossignoli P, Freitas JV, Takano L, Reis F, Caldeirão TD, Fernandes JN, Carr AM, Gaitero MVC, Corrente JE, Nunes HRC, Candido AF, Costa SMB, Dangió TD, Pascon T, Melo JVF, Takano L, Reis FVDS, Caldeirão TD, Carr AM, Garcia GA, Rabadan GB, Bassin HCM, Suyama KS, Damasceno LN, Takemoto MLS, Menezes MD, Bussaneli DG, Nogueira VKC, Lima PR, Lourenço IO, Marostica de Sá J, Megid RA, Caruso IP, Rasmussen LT, Prata GM, Piculo F, Vesentini G, Arantes MA, Ferraz GAR, Camargo LP, Kron MR, Corrente JE, Nunes HRC. Study protocol to investigate biomolecular muscle profile as predictors of long-term urinary incontinence in women with gestational diabetes mellitus. BMC Pregnancy Childbirth 2020; 20:117. [PMID: 32075598 PMCID: PMC7031907 DOI: 10.1186/s12884-020-2749-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 01/17/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pelvic floor muscles (PFM) and rectus abdominis muscles (RAM) of pregnant diabetic rats exhibit atrophy, co-localization of fast and slow fibers and an increased collagen type I/III ratio. However, the role of similar PFM or RAM hyperglycemic-related myopathy in women with gestational diabetes mellitus (GDM) remains poorly investigated. This study aims to assess the frequency of pelvic floor muscle disorders and pregnancy-specific urinary incontinence (PS-UI) 12 months after the Cesarean (C) section in women with GDM. Specifically, differences in PFM/RAM hyperglycemic myopathy will be evaluated. METHODS The Diamater is an ongoing cohort study of four groups of 59 pregnant women each from the Perinatal Diabetes Research Centre (PDRC), Botucatu Medical School (FMB)-UNESP (São Paulo State University), Brazil. Diagnosis of GDM and PS-UI will be made at 24-26 weeks, with a follow-up at 34-38 weeks of gestation. Inclusion in the study will occur at the time of C-section, and patients will be followed at 24-48 h, 6 weeks and 6 and 12 months postpartum. Study groups will be classified as (1) GDM plus PS-UI; (2) GDM without PS-UI; (3) Non-GDM plus PS-UI; and (4) Non-GDM without PS-UI. We will analyze relationships between GDM, PS-UI and hyperglycemic myopathy at 12 months after C-section. The mediator variables to be evaluated include digital palpation, vaginal squeeze pressure, 3D pelvic floor ultrasound, and 3D RAM ultrasound. RAM samples obtained during C-section will be analyzed for ex-vivo contractility, morphological, molecular and OMICS profiles to further characterize the hyperglycemic myopathy. Additional variables to be evaluated include maternal age, socioeconomic status, educational level, ethnicity, body mass index, weight gain during pregnancy, quality of glycemic control and insulin therapy. DISCUSSION To our knowledge, this will be the first study to provide data on the prevalence of PS-UI and RAM and PFM physical and biomolecular muscle profiles after C-section in mothers with GDM. The longitudinal design allows for the assessment of cause-effect relationships between GDM, PS-UI, and PFMs and RAMs myopathy. The findings may reveal previously undetermined consequences of GDM.
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Affiliation(s)
- Marilza V C Rudge
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil.
| | - Fátima P Souza
- Physics Department, Institute of Biosciences, Letters and Exact Sciences, Multiuser Center for Biomolecular Innovation, UNESP-São Paulo State University, Sao Paulo, Brazil
| | - Joelcio F Abbade
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil
| | - Raghavendra L S Hallur
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil
| | - João Paulo C Marcondes
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil
| | - Fernanda Piculo
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil.,Physiotherapy Department, Faculdades Integradas de Bauru, FIB, Sao Paulo, Brazil
| | - Gabriela Marini
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil.,Universidade do Sagrado Coração (USC), Jardim Brasil, Bauru, Sao Paulo, Brazil
| | - Giovana Vesentini
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil
| | - Lehana Thabane
- Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, ON, Canada.,Biostatistics Unit, Father Sean O'Sullivan Research Centre, St Joseph's Healthcare-Hamilton, Hamilton, ON, Canada
| | - Steven S Witkin
- Department of Obstetrics and Gynecology, Weill Cornell Medicine, New York, NY, USA.,Institute of Tropical Medicine, University of Sao Paulo Medical School, Sao Paulo, Brazil
| | - Iracema M P Calderon
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil
| | - Angélica M P Barbosa
- Department of Gynecology and Obstetrics, Botucatu Medical School (FMB), São Paulo State University (UNESP), CEP18618-687, Sao Paulo, Brazil.,School of Philosophy and Sciences, Department of Physiotherapy and Occupational Therapy, UNESP-São Paulo State University, Marília, Sao Paulo, Brazil
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Harper OJ, Boyé-Péronne S, Garcia GA, Hrodmarsson HR, Loison JC, Gans B. To see C 2: Single-photon ionization of the dicarbon molecule. J Chem Phys 2020; 152:041105. [PMID: 32007030 DOI: 10.1063/1.5139309] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The C2 carbon cluster is found in a large variety of environments including flames, electric discharges, and astrophysical media. Due to spin-selection rules, assessing a complete overview of the dense vibronic landscape of the C2 + cation starting from the ground electronic state X Σg+1 of the neutral is not possible, especially since the C2 + ground state is of X+ Σg-4 symmetry. In this work, a flow-tube reactor source is employed to generate the neutral C2 in a mixture of both the lowest singlet X Σg+1 and triplet a 3Πu electronic states. We have investigated the vibronic transitions in the vicinity of the first adiabatic ionization potential via one-photon ionization with vacuum ultraviolet synchrotron radiation coupled with electron/ion double imaging techniques. Using ab initio calculations and Franck-Condon simulations, three electronic transitions are identified and their adiabatic ionization energy is determined Ei(a+ 2Πu←X 1Σg +)=12.440(10) eV, Ei(X+ 4Σg -←a 3Πu)=11.795(10) eV, and Ei(a+2Πu ← a3Πu) = 12.361(10) eV. From the three origin bands, the following energy differences are extracted: ΔE(a - X) = 0.079(10) eV and ΔE(a+ - X+) = 0.567(10) eV. The adiabatic ionization potential corresponding to the forbidden one-photon transition X+ ← X is derived and amounts to 11.873(10) eV, in very good agreement with the most recent measurement by Krechkivska et al. [J. Chem. Phys. 144, 144305 (2016)]. The enthalpy of formation of the doublet ground state C2 + cation in the gas phase is determined at 0 K, ΔfH0(0K)(C2 +(Πu2))=2019.9(10) kJ mol-1. In addition, we report the first experimental ion yield of C2 for which only a simple estimate was used up to now in the photochemistry models of astrophysical media due to the lack of experimental data.
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Affiliation(s)
- Oliver J Harper
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Séverine Boyé-Péronne
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France
| | - Gustavo A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France
| | - Helgi R Hrodmarsson
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France
| | - Jean-Christophe Loison
- Institut des Sciences Moléculaires, UMR 5255 CNRS-Université de Bordeaux, Bât. A12, 351 cours de la Libération, F-33405 Talence Cedex, France
| | - Bérenger Gans
- Institut des Sciences Moléculaires d'Orsay, CNRS, Université Paris-Saclay, 91405 Orsay, France
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45
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Mukhopadhyay DP, Schleier D, Fischer I, Loison JC, Alcaraz C, Garcia GA. Photoelectron spectroscopy of boron-containing reactive intermediates using synchrotron radiation: BH 2, BH, and BF. Phys Chem Chem Phys 2020; 22:1027-1034. [PMID: 31854408 DOI: 10.1039/c9cp06010c] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mass selected slow photoelectron spectra (SPES) of three boron-containing reactive species, BH2, BH, and BF were recorded by double imaging photoion-photoelectron coincidence spectroscopy (i2PEPICO) using synchrotron radiation. All species were generated in a flow reactor from the H-abstraction of B2H6 by F atoms created in a F2 microwave discharge. The spectrum of BH2+ exhibits a long bending mode progression with a 970 cm-1 spacing due to the large geometry change from bent to linear upon ionization. Its ionization energy was determined as 8.12 ± 0.02 eV. For BH, photoionisation from both X1Σ+ singlet and a3Π triplet state was observed, permitting the experimental determination of the singlet/triplet gap (ΔEST) from the observed IE's of 9.82 eV and 8.48 eV. In addition, a threshold photoelectron spectrum of BF was recorded, which leads to an IE of 11.11 eV and an improved value for νBF+ of 1690 cm-1. All spectra were simulated by calculating Franck-Condon factors from optimised structures based on quantum chemical calculations.
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Affiliation(s)
- D P Mukhopadhyay
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - D Schleier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - I Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany.
| | - J-C Loison
- ISM-CNRS, Université de Bordeaux, 351 cours de la Libération, F-, 33405 Talence, France
| | - C Alcaraz
- LCP, UMR 8000, CNRS-Univ. Paris-Sud and Paris Saclay, Bât. 350, Centre Universitaire Paris-Sud, F-91405 Orsay, France
| | - G A Garcia
- Synchrotron SOLEIL, L'Orme des Merisiers, St Aubin, B.P. 48, F-91192 Gif sur Yvette, France
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46
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Bourgalais J, Gouid Z, Herbinet O, Garcia GA, Arnoux P, Wang Z, Tran LS, Vanhove G, Hochlaf M, Nahon L, Battin-Leclerc F. Isomer-sensitive characterization of low temperature oxidation reaction products by coupling a jet-stirred reactor to an electron/ion coincidence spectrometer: case of n-pentane. Phys Chem Chem Phys 2020; 22:1222-1241. [DOI: 10.1039/c9cp04992d] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using a tunable vacuum ultraviolet synchrotron beam line and first principle computations, a jet-stirred reactor was coupled for the first time to a photoionization mass spectrometer using electron/ion coincidence imaging.
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Affiliation(s)
- Jérémy Bourgalais
- LATMOS/IPSL
- UVSQ Université Paris-Saclay
- Sorbonne Université
- CNRS
- Guyancourt
| | - Zied Gouid
- Université Gustave Eiffel
- COSYS/LISIS
- Champs sur Marne
- France
| | - Olivier Herbinet
- CNRS
- Université de Lorraine
- Laboratoire Réactions et Génie des Procédés
- UPR 3349
- Nancy F-54000
| | - Gustavo A. Garcia
- Synchrotron SOLEIL
- L’Orme des Merisiers
- 91192 Gif-sur-Yvette Cedex
- France
| | | | - Zhandong Wang
- National Synchrotron Radiation Laboratory
- University of Science and Technology of China
- Hefei
- People's Republic of China
| | - Luc-Sy Tran
- Physicochimie des Processus de Combustion et de l’Atmosphère (PC2A)
- UMR 8522 CNRS
- Université de Lille
- F-59000 Lille
- France
| | - Guillaume Vanhove
- Physicochimie des Processus de Combustion et de l’Atmosphère (PC2A)
- UMR 8522 CNRS
- Université de Lille
- F-59000 Lille
- France
| | - Majdi Hochlaf
- Université Gustave Eiffel
- COSYS/LISIS
- Champs sur Marne
- France
| | - Laurent Nahon
- Synchrotron SOLEIL
- L’Orme des Merisiers
- 91192 Gif-sur-Yvette Cedex
- France
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47
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Tang X, Garcia GA, Nahon L. High resolution vibronic state-specific dissociation of NO2+in the 10.0–15.5 eV energy range by synchrotron double imaging photoelectron photoion coincidence. Phys Chem Chem Phys 2020; 22:1974-1982. [DOI: 10.1039/c9cp05847h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Low-lying electronic states of NO2+are prepared with vibrational structures and their state-specific dissociation mechanisms are unraveled with high-resolution i2PEPICO.
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Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- Chinese Academy of Sciences
- Hefei
- China
| | | | - Laurent Nahon
- Synchrotron SOLEIL
- L’Orme des Merisiers
- 91192 Gif sur Yvette
- France
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48
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Tang X, Lin X, Garcia GA, Loison JC, Gouid Z, Abdallah HH, Fittschen C, Hochlaf M, Gu X, Zhang W, Nahon L. Identifying isomers of peroxy radicals in the gas phase: 1-C3H7O2vs. 2-C3H7O2. Chem Commun (Camb) 2020; 56:15525-15528. [DOI: 10.1039/d0cc06516a] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The two isomers of propylperoxy radical 1-C3H7O2 and 2-C3H7O2, together with their rotamers, are individually identified and assigned.
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Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | - Xiaoxiao Lin
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | | | | | - Zied Gouid
- Université Gustave Eiffel
- COSYS/LISIS
- Champs sur Marne
- France
- Laboratoire de Caractérisations, Applications et Modélisations des Matériaux
| | - Hassan H. Abdallah
- Department of Chemistry
- College of Education
- Salahaddin University-Erbil
- 44002 Erbil
- Iraq
| | - Christa Fittschen
- University Lille
- CNRS
- UMR 8522
- PC2A – Physicochimie des Processus de Combustion et de l’Atmosphère
- F-59000 Lille
| | - Majdi Hochlaf
- Université Gustave Eiffel
- COSYS/LISIS
- Champs sur Marne
- France
| | - Xuejun Gu
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | - Weijun Zhang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | - Laurent Nahon
- Synchrotron SOLEIL
- L’Orme des Merisiers
- 91192 Gif sur Yvette
- France
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49
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Gans B, Hartweg S, Garcia GA, Boyé-Péronne S, Harper OJ, Guillemin JC, Loison JC. VUV photoionization of the CH2NC radical: adiabatic ionization energy and cationic vibrational mode wavenumber determinations. Phys Chem Chem Phys 2020; 22:12496-12501. [DOI: 10.1039/d0cp01901a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The photoelectron spectroscopy of CH2NC (isocyanomethyl) radical species is investigated for the first time between 9.3 and 11.2 eV in the vicinity of the first photoionizing transition X+1A1 ← X 2B1.
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Affiliation(s)
- Bérenger Gans
- Institut des Sciences Moléculaires d’Orsay
- CNRS
- Université Paris-Saclay
- F-91405 Orsay
- France
| | - Sebastian Hartweg
- Synchrotron SOLEIL
- L’Orme des Merisiers
- F-91192 Gif sur Yvette Cedex
- France
| | - Gustavo A. Garcia
- Synchrotron SOLEIL
- L’Orme des Merisiers
- F-91192 Gif sur Yvette Cedex
- France
| | - Séverine Boyé-Péronne
- Institut des Sciences Moléculaires d’Orsay
- CNRS
- Université Paris-Saclay
- F-91405 Orsay
- France
| | - Oliver J. Harper
- Institut des Sciences Moléculaires d’Orsay
- CNRS
- Université Paris-Saclay
- F-91405 Orsay
- France
| | - Jean-Claude Guillemin
- Univ. Rennes
- Ecole Nationale Supérieure de Chimie de Rennes
- CNRS
- ISCR – UMR6226
- F-35000 Rennes
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50
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Tang X, Garcia GA, Nahon L. High-resolution vacuum ultraviolet photodynamic of the nitrogen dioxide dimer (NO2)2 and the stability of its cation. Phys Chem Chem Phys 2020; 22:21068-21073. [DOI: 10.1039/d0cp03495a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mass-selected TPES of the dimer N2O4 is recorded and its VUV photodynamics shows the dimer cation N2O4+ is unstable.
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Affiliation(s)
- Xiaofeng Tang
- Laboratory of Atmospheric Physico-Chemistry
- Anhui Institute of Optics and Fine Mechanics
- HFIPS
- Chinese Academy of Sciences
- Hefei
| | | | - Laurent Nahon
- Synchrotron SOLEIL
- L’Orme des Merisiers
- Gif sur Yvette 91192
- France
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