1
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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] [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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2
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Petersen AC, Sølling TI. Dissociation processes of ionized freons: CHFCl2+ and CF2Cl2+ in the gas phase. J Chem Phys 2023; 159:174306. [PMID: 37921250 DOI: 10.1063/5.0169883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 10/13/2023] [Indexed: 11/04/2023] Open
Abstract
The present study reveals the effects of symmetry on how the distribution and flow of energy play out on the decomposition of small halocarbons. Unimolecular decay of the freons CHFCl2 and CF2Cl2 when ionized has been investigated. Mass spectrometric results that encompass isotope effects (peak heights) and energy distribution in the exit channel (peak shapes) are interpreted by computational methods. Non-statistical processes of electronic predissociation and isolated state decay are shown to be directly associated with molecular symmetry.
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Affiliation(s)
- Allan Christian Petersen
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen, DK 2100, Denmark
| | - Theis Ivan Sølling
- Center for Integrative Petroleum Research, College of Petroleum and Geosciences, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
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3
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Hemberger P, Pan Z, Wu X, Zhang Z, Kanayama K, Bodi A. Photoion Mass-Selected Threshold Photoelectron Spectroscopy to Detect Reactive Intermediates in Catalysis: From Instrumentation and Examples to Peculiarities and a Database. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:16751-16763. [PMID: 37670794 PMCID: PMC10476201 DOI: 10.1021/acs.jpcc.3c03120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/04/2023] [Indexed: 09/07/2023]
Abstract
Photoion mass-selected threshold photoelectron spectroscopy (ms-TPES) is a synchrotron-based, universal, sensitive, and multiplexed detection tool applied in the areas of catalysis, combustion, and gas-phase reactions. Isomer-selective vibrational fingerprints in the ms-TPES of stable and reactive intermediates allow for unequivocal assignment of spectral carriers. Case studies are presented on heterogeneous catalysis, revealing the role of ketenes in the methanol-to-olefins process, the catalytic pyrolysis mechanism of lignin model compounds, and the radical chemistry upon C-H activation in oxyhalogenation. These studies demonstrate the potential of ms-TPES as an analytical technique for elucidating complex reaction mechanisms. We examine the robustness of ms-TPES assignments and address sampling effects, especially the temperature dependence of ms-TPES due to rovibrational broadening. Data acquisition approaches and the Stark shift from the extraction field are also considered to arrive at general recommendations. Finally, the PhotoElectron PhotoIon Spectral Compendium (https://pepisco.psi.ch), a spectral database hosted at Paul Scherrer Institute to support assignment, is introduced.
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Affiliation(s)
| | - Zeyou Pan
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Xiangkun Wu
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Zihao Zhang
- Paul
Scherrer Institute, Villigen 5232, Switzerland
| | - Keisuke Kanayama
- Paul
Scherrer Institute, Villigen 5232, Switzerland
- Institute
of Fluid Science, Tohoku University 2-1-1 Katahira, Aoba, Sendai 980-8577, Miyagi, Japan
- Graduate
School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba, Sendai 980-8579, Miyagi, Japan
| | - Andras Bodi
- Paul
Scherrer Institute, Villigen 5232, Switzerland
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4
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Bodi A, Hafliðason A, Kvaran Á. Branching ratios in the dissociative photoionization of iodomethane by photoelectron photoion coincidence. Phys Chem Chem Phys 2023; 25:7383-7393. [PMID: 36826403 DOI: 10.1039/d2cp03339a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Iodomethane yields ten fragment ions after valence photoionization, in part by multiple dissociation pathways for each, thanks to a plethora of electronic states available in the parent ion as well as in the fragments. The comprehensive breakdown diagram from 11 eV to the double ionization onset, i.e., 26.7 eV, is recorded at high resolution using double imaging photoelectron photoion coincidence spectroscopy with synchrotron vacuum ultraviolet radiation. Based on fragment ion groupings, the changing branching ratios between these groups and between fragment ions within each group, as well as ancillary thermochemistry, we provide an overview of the dissociation pathways at play. Statistical and impulsive dissociations are identified using kinetic energy release analysis. Finally, a newly observed regime change is discussed in double ionization, whereby coincident H+ + I+ formation dominates over a 4 eV photon energy range, outcompeting the normally prevailing CH3+ + I+ channel.
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Affiliation(s)
- Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland.
| | - Arnar Hafliðason
- Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland
| | - Ágúst Kvaran
- Science Institute, University of Iceland, Dunhagi 3, 107 Reykjavík, Iceland
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5
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Fürst S, Haasler M, Grotjahn R, Kaupp M. Full Implementation, Optimization, and Evaluation of a Range-Separated Local Hybrid Functional with Wide Accuracy for Ground and Excited States. J Chem Theory Comput 2023; 19:488-502. [PMID: 36625881 DOI: 10.1021/acs.jctc.2c00782] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We report the first full and efficient implementation of range-separated local hybrid functionals (RSLHs) into the TURBOMOLE program package. This enables the computation of ground-state energies and nuclear gradients as well as excitation energies. Regarding the computational effort, RSLHs scale like regular local hybrid functionals (LHs) with system or basis set size and increase timings by a factor of 2-3 in total. An advanced RSLH, ωLH22t, has been optimized for atomization energies and reaction barriers. It is an extension of the recent LH20t local hybrid and is based on short-range PBE and long-range HF exchange-energy densities, a pig2 calibration function to deal with the gauge ambiguity of exchange-energy densities, and reoptimized B95c correlation. ωLH22t has been evaluated for a wide range of ground-state and excited-state quantities. It further improves upon the already successful LH20t functional for the GMTKN55 main-group energetics test suite, and it outperforms any global hybrid while performing close to the top rung-4 functional, ωB97M-V, for these evaluations when augmented by D4 dispersion corrections. ωLH22t performs excellently for transition-metal reactivity and provides good balance between delocalization errors and left-right correlation for mixed-valence systems, with a somewhat larger bias toward localized states compared to LH20t. It approaches the accuracy of the best local hybrids to date for core, valence singlet and triplet, and Rydberg excitation energies while improving strikingly on intra- and intermolecular charge-transfer excitations, comparable to the most successful range-separated hybrids available.
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Affiliation(s)
- Susanne Fürst
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Matthias Haasler
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Robin Grotjahn
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Martin Kaupp
- Institut für Chemie, Theoretische Chemie/Quantenchemie, Sekr. C7, Technische Universität Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
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6
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Giustini A, Winfough M, Czekner J, Sztáray B, Meloni G, Bodi A. Photoionization of Two Potential Biofuel Additives: γ-Valerolactone and Methyl Butyrate. J Phys Chem A 2021; 125:10711-10724. [PMID: 34918933 DOI: 10.1021/acs.jpca.1c08033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The photoionization of two potential biofuel additives, γ-valerolactone (GVL, C5H8O2) and methyl butyrate (MB, C5H10O2) has been studied by imaging photoelectron photoion coincidence spectroscopy (iPEPICO) at the VUV beamline of the Swiss Light Source (SLS). The vibrational fine structure in the photoelectron spectrum is compared with a Franck-Condon simulation for the electronic ground-state band of the GVL cation. In the lowest energy dissociative photoionization channel of GVL, CO2 is lost, resulting in a 1-butene fragment ion with a 0 K appearance energy of E0 = 10.35 ± 0.01 eV. A newly calculated 1-butene ionization energy of 9.595 ± 0.015 eV establishes the reverse barrier height to CO2 loss as 66.6 ± 4.3 kJ mol-1. Methyl butyrate cations undergo McLafferty rearrangement, which explains the missing ion signal at the computed adiabatic ionization energy of 9.25 eV. After H transfer, ethylene is lost in the lowest energy dissociation channel to yield the methyl acetate enol ion at E0 = 10.24 ± 0.04 eV. This value connects the energetics of methyl butyrate with that of methyl acetate enol ion, which is established at ΔfHo0K[CH2C(OH)OCH3+] = 502 ± 6 kJ mol-1. Parallel to ethylene loss, methyl loss is also observed from the enol tautomer of the parent ion. Both samples exhibit low-energy nonstatistical dissociative ionization channels. In GVL, the methyl-loss abundance rises quickly but levels off suddenly in the energy range of the first electronically excited states, indicating nonstatistical competition between CH3 and CO2 loss. In MB, the major parallel dissociation channel is the loss of a methoxy radical. Calculations indicate that McLafferty rearrangement is inhibited on the excited-state surface. Indeed, breakdown curve modeling of this and a sequential CO-loss channel confirms a second statistical regime in dissociative photoionization, decoupled from ethylene loss.
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Affiliation(s)
- Andrea Giustini
- Dipartimento di Scienze Fisiche e Chimiche, University of L'Aquila, 67100 L'Aquila, Italy
| | - Matthew Winfough
- Department of Chemistry, University of San Francisco, 2130 Fulton Street, San Francisco, California 94117-1080, United States
| | - Joseph Czekner
- Institut für Physikalische Chemie II, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany
| | - Bálint Sztáray
- Department of Chemistry, University of the Pacific, 3601 Pacific Avenue, Stockton, California 95211, United States
| | - Giovanni Meloni
- Dipartimento di Scienze Fisiche e Chimiche, University of L'Aquila, 67100 L'Aquila, Italy.,Department of Chemistry, University of San Francisco, 2130 Fulton Street, San Francisco, California 94117-1080, United States
| | - Andras Bodi
- Laboratory for Femtochemistry and Synchrotron Radiation, Paul Scherrer Institut (PSI), 5232 Villigen, Switzerland
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7
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Bodi A, Hemberger P, Tuckett RP. From Energetics to Intracluster Chemistry: Valence Photoionization of Trifluoromethylsulfur Pentafluoride (CF 3SF 5) by Double Velocity Map Imaging. J Phys Chem A 2021; 125:2601-2611. [PMID: 33729793 DOI: 10.1021/acs.jpca.1c00918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trifluoromethylsulfur pentafluoride (CF3SF5) was valence threshold photoionized in a double imaging photoelectron photoion coincidence spectrometer using vacuum ultraviolet synchrotron radiation. In the 12.5-16.4 eV photon energy range, CF3+, SF5+, and SF3+ cations were observed in both room temperature (RT) and molecular beam (MB) experiments. Their fractional abundances exhibited differences beyond the sample temperature. Kinetic energy analysis of the fragment ions confirmed the difference in the dissociative photoionization mechanism. In the RT experiment, the CF3+ kinetic energies were extrapolated to a 11.84 ± 0.15 eV threshold, which was used in an ion cycle to determine the enthalpy of formation of CF3SF5 as ΔfH°298K(CF3SF5) = -1593 ± 16 kJ mol-1. We also updated the enthalpy of formation of the sulfur pentafluoride radical as ΔfH°298K(SF5) = -854 ± 7 kJ mol-1 and discuss the discrepancy between the CF3 ionization energy based on the Active Thermochemical Tables and the value anchored to the CF ionization energy. A computed reaction enthalpy network optimization resulted in ΔfH°298K(CF3SF5) = -1608 ± 20 kJ mol-1. Both values for ΔfH°298K(CF3SF5) agree with previous ab initio ones in contrast to the original, experimental determination. SF3+ is formed by F-transfer processes both in the RT and MB experiments. Although the same peaks were observed in both experiments, the lower SF3+ onset energy and the more slowly rising CF3+ kinetic energy release in the MB experiment revealed clustering and intracluster F-transfer reactions upon ionization. The monomer and dimer cation potential energy surfaces were explored to rationalize the observations. In the dimer cation, the observer CF3SF5 catalyzes fluorine transfer and promotes CF4 formation, which ultimately leads to the SF3+ fragment ion.
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Affiliation(s)
- Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Richard P Tuckett
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, U.K
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8
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Majer K, Signorell R, Heringa MF, Goldmann M, Hemberger P, Bodi A. Valence Photoionization of Thymine: Ionization Energies, Vibrational Structure, and Fragmentation Pathways from the Slow to the Ultrafast. Chemistry 2019; 25:14192-14204. [PMID: 31469456 DOI: 10.1002/chem.201903282] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Indexed: 11/06/2022]
Abstract
The photoionization of thymine has been studied by using vacuum ultraviolet radiation and imaging photoelectron photoion coincidence spectroscopy after aerosol flash vaporization and bulk evaporation. The two evaporation techniques have been evaluated by comparison of the photoelectron spectra and breakdown diagrams. The adiabatic ionization energies for the first four electronic states were determined to be 8.922±0.008, 9.851±0.008, 10.30±0.02, and 10.82±0.01 eV. Vibrational features have been assigned for the first three electronic states with the help of Franck-Condon factor calculations based on density functional theory and wave function theory vibrational analysis within the harmonic approximation. The breakdown diagram of thymine, as supported by composite method ab initio calculations, suggests that the main fragment ions are formed in sequential HNCO-, CO-, and H-loss dissociation steps from the thymine parent ion, with the first step corresponding to a retro-Diels-Alder reaction. The dissociation rate constants were extracted from the photoion time-of-flight distributions and used together with the breakdown curves to construct a statistical model to determine 0 K appearance energies of 11.15±0.16 and 11.95±0.09 eV for the m/z 83 and 55 fragment ions, respectively. These results have allowed us to revise previously proposed fragmentation mechanisms and to propose a model for the final, nonstatistical H-loss step in the breakdown diagram, yielding the m/z 54 fragment ion at an appearance energy of 13.24 eV.
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Affiliation(s)
- Katharina Majer
- Paul Scherrer Institute, 5232, Villigen, Switzerland.,Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, 8093, Zürich, Switzerland
| | - Ruth Signorell
- Department of Chemistry and Applied Biosciences, Laboratory of Physical Chemistry, ETH Zürich, 8093, Zürich, Switzerland
| | - Maarten F Heringa
- Paul Scherrer Institute, 5232, Villigen, Switzerland.,Present address: Givaudan Schweiz AG, 8310, Kemptthal, Switzerland
| | - Maximilian Goldmann
- Gymnasium Lerbermatt, 3098, Köniz, Switzerland.,Hochschule Luzern - Technik & Architektur, 6048, Horw, Switzerland
| | | | - Andras Bodi
- Paul Scherrer Institute, 5232, Villigen, Switzerland
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9
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Bodi A, Hemberger P. Low-Energy Photoelectron Spectrum and Dissociative Photoionization of the Smallest Amides: Formamide and Acetamide. J Phys Chem A 2018; 123:272-283. [DOI: 10.1021/acs.jpca.8b10373] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Andras Bodi
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Patrick Hemberger
- Laboratory for Synchrotron Radiation and Femtochemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
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10
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Wu X, Wu M, Tang X, Zhou X, Liu S, Liu F, Sheng L. Cl-Loss Dynamics of Vinyl Chloride Cations in the B2A″ State: Role of the C2A′ State. J Phys Chem A 2017; 121:4743-4753. [DOI: 10.1021/acs.jpca.7b03636] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | - Fuyi Liu
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
| | - Liusi Sheng
- National
Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui 230029, China
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11
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Baer T, Tuckett RP. Advances in threshold photoelectron spectroscopy (TPES) and threshold photoelectron photoion coincidence (TPEPICO). Phys Chem Chem Phys 2017; 19:9698-9723. [DOI: 10.1039/c7cp00144d] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The history and evolution of molecular threshold photoelectron spectroscopy and threshold photoelectron photoion coincidence spectroscopy (TPEPICO) over the last fifty years are reviewed.
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Affiliation(s)
- Tomas Baer
- Chemistry Department
- University of North Carolina
- Chapel Hill
- USA
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12
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Huang CH, Chou SY, Jang SB, Lin YC, Li CE, Chen CC, Chang JL. Insights into the Photoelectron Spectroscopy of Chlorofluoroethenes Studied by Density-Functional and Coupled-Cluster Theories. J Phys Chem A 2016; 120:1175-83. [PMID: 26884146 DOI: 10.1021/acs.jpca.5b11158] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The first two ionic states of chlorofluoroethenes were studied by using both time-independent and time-dependent density-functional theories. We calculated the equilibrium geometries and harmonic vibrational frequencies of 1,1-, cis-, and trans-C2H2FCl and their cations by using the B3LYP and B3PW91 functionals together with the cc-pVTZ and aug-cc-pVTZ basis sets. Franck-Condon factors were computed by the method developed in our group, in which the Duschinsky effect was treated explicitly. A new technique, named alignment transformation, followed by Euler transformations was developed to achieve the Eckart conditions. The adiabatic ionization energies were calculated by the CCSD(T) method extrapolated to the complete basis set limit. Insights into the simulated photoelectron spectra of C2H2FCl indicate that the resolutions of recent threshold photoelectron experiments are not high enough to detect individual transitions. The high-resolution photoelectron spectra of C2H2FCl are predicted for future reference. The computed adiabatic ionization energies of the three isomers of C2H2FCl are in accord with the experiments with the absolute deviations ranging from 0.004 to 0.021 eV. We suggest that the agreement between experimental and theoretical spectra should be a key criterion to judge whether a spectral assignment is reasonable.
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Affiliation(s)
- Cyong-Huei Huang
- Department of Science Education and Application, National Taichung University of Education , Taichung 40306, Taiwan, Republic of China
| | - Shang-Yi Chou
- Department of Science Education and Application, National Taichung University of Education , Taichung 40306, Taiwan, Republic of China
| | - Shiu-Bau Jang
- Department of Science Education and Application, National Taichung University of Education , Taichung 40306, Taiwan, Republic of China
| | - Yu-Chieh Lin
- Department of Science Education and Application, National Taichung University of Education , Taichung 40306, Taiwan, Republic of China
| | - Chien-En Li
- Department of Science Education and Application, National Taichung University of Education , Taichung 40306, Taiwan, Republic of China
| | - Chiing-Chang Chen
- Department of Science Education and Application, National Taichung University of Education , Taichung 40306, Taiwan, Republic of China
| | - Jia-Lin Chang
- Department of Science Education and Application, National Taichung University of Education , Taichung 40306, Taiwan, Republic of China
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13
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Savee JD, Zádor J, Hemberger P, Sztáray B, Bodi A, Osborn DL. Threshold photoelectron spectrum of the benzyl radical. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1021398] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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A theoretical study on the equilibrium structures, vibrational frequencies and photoelectron spectroscopy of thiocarbonyl fluoride by using density functional and coupled-cluster theories. Chem Phys 2014. [DOI: 10.1016/j.chemphys.2014.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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15
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Parkes MA, Simpson MJ, Mikhailov V, Tuckett RP. The kinetics and product state distributions from gas-phase reactions of small atomic and molecular cations with C2H4, C2H3F, 1,1-C2H2F2, C2HF3 and C2F4. Phys Chem Chem Phys 2014; 16:3726-38. [PMID: 24418988 DOI: 10.1039/c3cp54881c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reactions of twenty one gas-phase cations with C2H3F, 1,1-C2H2F2, C2HF3 and C2F4 have been studied in a selected ion flow tube at 298 K. The cations are both atomic and molecular with recombination energies in the range 6-22 eV, and the kinetics and branching ratios into product ions are revealed for all the reactions. These data, together with that from an earlier study of reactions of C(x)F(y)(+) with these four fluorinated ethenes (J. Phys. Chem. A., 2012, 116, 8119), are compared with the reactions of these ions with C2H4, where available. Nearly all the reactions have a rate coefficient close to the collisional value calculated by either Langevin or modified average dipole orientation theories. The products of the reactions of N(+) and N2(+) with C2H4 are found to be anomalous, compared to their reactions with the four fluorinated ethenes. The branching ratios into product cations are compared with those from a high resolution (ca. 0.002 eV) photoionisation (hν = 10-22 eV) study of C2H3F, 1,1-C2H2F2, C2HF3 and C2F4 (Phys. Chem. Chem. Phys., 2012, 14, 3935) in order to gauge the importance of electron transfer in ion-molecule reactions. The higher the recombination energy of the cation, the better the agreement between the two sets of product branching ratios. Where there is disagreement at lower recombination energies, it appears that there is more fragmentation of the products in the photoionisation experiment compared to the ion-molecule reactions.
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Affiliation(s)
- Michael A Parkes
- School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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16
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Osswald P, Hemberger P, Bierkandt T, Akyildiz E, Köhler M, Bodi A, Gerber T, Kasper T. In situ flame chemistry tracing by imaging photoelectron photoion coincidence spectroscopy. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:025101. [PMID: 24593390 DOI: 10.1063/1.4861175] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Adaptation of a low-pressure flat flame burner with a flame-sampling interface to the imaging photoelectron photoion coincidence spectrometer (iPEPICO) of the VUV beamline at the Swiss Light Source is presented. The combination of molecular-beam mass spectrometry and iPEPICO provides a new powerful analytical tool for the detailed investigation of reaction networks in flames. First results demonstrate the applicability of the new instrument to comprehensive flame diagnostics and the potentially high impact for reaction mechanism development for conventional and alternative fuels. Isomer specific identification of stable and radical flame species is demonstrated with unrivaled precision. Radical detection and identification is achieved for the initial H-abstraction products of fuel molecules as well as for the reaction controlling H, O, and OH radicals. Furthermore, quantitative evaluation of changing species concentrations during the combustion process and the applicability of respective results for kinetic model validation are demonstrated. Utilization of mass-selected threshold photoelectron spectra is shown to ensure precise signal assignment and highly reliable spatial profiles.
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Affiliation(s)
- P Osswald
- German Aerospace Center (DLR) - Institute of Combustion Technology, Stuttgart 70569, Germany
| | - P Hemberger
- Molecular Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - T Bierkandt
- Mass Spectrometry in Reactive Flows - Thermodynamics (IVG), University of Duisburg-Essen, Duisburg, Germany
| | - E Akyildiz
- Mass Spectrometry in Reactive Flows - Thermodynamics (IVG), University of Duisburg-Essen, Duisburg, Germany
| | - M Köhler
- German Aerospace Center (DLR) - Institute of Combustion Technology, Stuttgart 70569, Germany
| | - A Bodi
- Molecular Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - T Gerber
- Molecular Dynamics Group, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - T Kasper
- Mass Spectrometry in Reactive Flows - Thermodynamics (IVG), University of Duisburg-Essen, Duisburg, Germany
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Bodi A, Hemberger P. Imaging breakdown diagrams for bromobutyne isomers with photoelectron–photoion coincidence. Phys Chem Chem Phys 2014; 16:505-15. [DOI: 10.1039/c3cp53212g] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Harvey J, Tuckett RP, Bodi A. Shining new light on the multifaceted dissociative photoionisation dynamics of CCl4. Phys Chem Chem Phys 2014; 16:20492-9. [DOI: 10.1039/c4cp03009e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Statisticality restored: high internal energy CCl4+ dissociates mostly according to statistical theory, and an intersystem crossing path precludes fluorescence.
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Affiliation(s)
- Jonelle Harvey
- School of Chemistry
- University of Birmingham
- Birmingham B15 2TT, UK
| | | | - Andras Bodi
- Molecular Dynamics Group
- Swiss Light Source
- Paul Scherrer Institut
- Villigen 5232, Switzerland
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19
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Bodi A. Internal energy selection in vacuum ultraviolet photoionization of ethanol and ethanol dimers. J Chem Phys 2013; 139:144306. [DOI: 10.1063/1.4824135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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