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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] [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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2
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Neumark DM. Spectroscopy of Radicals, Clusters, and Transition States Using Slow Electron Velocity-Map Imaging of Cryogenically Cooled Anions. J Phys Chem A 2023; 127:4207-4223. [PMID: 37094039 DOI: 10.1021/acs.jpca.3c01537] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Slow electron velocity-map imaging of cryogenically cooled anions (cryo-SEVI) is a high-resolution variant of anion photoelectron spectroscopy that has been applied with considerable success over the years to the study of radicals, size-selected clusters, and transition states for unimolecular and bimolecular reactions. Cryo-SEVI retains the versatility of conventional anion photoelectron spectroscopy while offering sub-meV resolution, thereby enabling the resolution of vibrational structure in the photoelectron spectra of complex anions. This Feature Article describes recent experiments in our laboratory using cryo-SEVI, including a new research direction in which anions are vibrationally pre-excited with an infrared laser pulse prior to photodetachment.
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Affiliation(s)
- Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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3
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Beyer M, Merkt F. Structure and dynamics of HD + in the vicinity of the H + + D and D + + H dissociation thresholds: Feshbach resonances and the role of g/u-symmetry breaking. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2048108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Maximilian Beyer
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
- Department of Physics and Astronomy, Vrije Universiteit, Amsterdam, The Netherlands
| | - Frédéric Merkt
- Laboratory of Physical Chemistry, ETH Zurich, Zurich, Switzerland
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4
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Liu Y, Zhu GZ, Yuan DF, Qian CH, Zhang YR, Rubenstein BM, Wang LS. Observation of a Symmetry-Forbidden Excited Quadrupole-Bound State. J Am Chem Soc 2020; 142:20240-20246. [PMID: 33185446 DOI: 10.1021/jacs.0c10552] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We report the observation of a symmetry-forbidden excited quadrupole-bound state (QBS) in the tetracyanobenzene anion (TCNB-) using both photoelectron and photodetachment spectroscopies of cryogenically-cooled anions. The electron affinity of TCNB is accurately measured as 2.4695 eV. Photodetachment spectroscopy of TCNB- reveals selected symmetry-allowed vibronic transitions to the QBS, but the ground vibrational state was not observed because the transition from the ground state of TCNB- (Au symmetry) to the QBS (Ag symmetry) is triply forbidden by the electric and magnetic dipoles and the electric quadrupole. The binding energy of the QBS is found to be 0.2206 eV, which is unusually large due to strong correlation and polarization effects. A centrifugal barrier is observed for near-threshold autodetachment, as well as relaxations from the QBS vibronic levels to the ground and a valence excited state of TCNB-. The current study shows a rare example where symmetry selection rules, rather than the Franck-Condon principle, govern vibronic transitions to a nonvalence state in an anion.
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Affiliation(s)
- Yuan Liu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Guo-Zhu Zhu
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Dao-Fu Yuan
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Chen-Hui Qian
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Yue-Rou Zhang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Brenda M Rubenstein
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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5
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Babin MC, DeVine JA, DeWitt M, Stanton JF, Neumark DM. High-Resolution Photoelectron Spectroscopy of Cryogenically Cooled NO 3̅. J Phys Chem Lett 2020; 11:395-400. [PMID: 31765169 DOI: 10.1021/acs.jpclett.9b03055] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
High-resolution anion photoelectron spectra of cryogenically cooled NO3̅ anions obtained using slow photoelectron velocity-map imaging are presented and provide new insight into the vibronic structure of the corresponding neutral radical. A combination of improved spectral resolution, measurement of energy-dependent intensity effects, temperature control, and comparison to theory allows for full assignment of the vibronic features observed in this spectrum. We obtain a refined electron affinity of 3.9289(14) eV for NO3. Further, the appearance of Franck-Condon forbidden transitions from vibrationally cold anions to neutral states with excitation along the NO3 ν4 mode confirms that these features arise from vibronic coupling with the B̃2E' excited state of NO3 and are not hot bands, as has been suggested. Together, the suite of experimental and simulated results provides clear evidence that the ν3 fundamental of NO3 resides near 1050 cm-1, addressing a long-standing controversy surrounding this vibrational assignment.
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Affiliation(s)
- Mark C Babin
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Jessalyn A DeVine
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - Martin DeWitt
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
| | - John F Stanton
- Quantum Theory Project, Department of Chemistry and Physics , University of Florida , Gainesville , Florida 32611 , United States
| | - Daniel M Neumark
- Department of Chemistry , University of California , Berkeley , California 94720 , United States
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
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6
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Wang L, Zhang S, Wang Y, Zhang B. Effect of hydrogen bonding on the nonradiative properties of dibenzofuran. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2020; 224:117466. [PMID: 31422340 DOI: 10.1016/j.saa.2019.117466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 07/27/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Femtosecond time-resolved transient absorption spectroscopy is employed to investigate the ultrafast excited-state dynamics from the S2 state of dibenzofuran and the hydrogen bonding effect in protic and aprotic solvents. Following the excitation with 266 nm, the initial population on the S2 state couples to the S1 state via internal conversion on tens of picoseconds. Afterwards, vibrational energy relaxation (VER) with dozens of picoseconds is determined in all solvents and strongly depended on the polarities of aprotic solvents. And the rising species related with the hydrogen-bonded intermediate S⁎ state are observed just in ethanol and methanol with the higher Kamlet parameter α. Subsequently, the intersystem crossing from the S1 state to the triplet manifold is a main deactivation pathway with the decay time of ≫ns. All the relaxation processes exhibit solvent dependence, indicating that hydrogen bonding interaction between solute and solvent enhances VER and significantly influences on the excited state dynamics of dibenzofuran.
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Affiliation(s)
- Lian Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; Graduate School of the Chinese Academy of Sciences, Beijing, PR China
| | - Song Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China.
| | - Ye Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China; Graduate School of the Chinese Academy of Sciences, Beijing, PR China
| | - Bing Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China.
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7
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Laws BA, Cavanagh SJ, Lewis BR, Gibson ST. Wigner Near-Threshold Effects in the Photoelectron Angular Distribution of NO2–. J Phys Chem A 2019; 123:10418-10425. [DOI: 10.1021/acs.jpca.9b09073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. A. Laws
- Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia
| | - S. J. Cavanagh
- Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia
| | - B. R. Lewis
- Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia
| | - S. T. Gibson
- Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia
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8
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Jacovella U, Merkt F. High-resolution photoelectron spectrum of the origin band of the X̃ + 2E ← X̃ 1A 1 ionising transition of propyne. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1451002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- U. Jacovella
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich , Zurich, Switzerland
| | - F. Merkt
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich , Zurich, Switzerland
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9
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DeVine JA, Weichman ML, Laws B, Chang J, Babin MC, Balerdi G, Xie C, Malbon CL, Lineberger WC, Yarkony DR, Field RW, Gibson ST, Ma J, Guo H, Neumark DM. Encoding of vinylidene isomerization in its anion photoelectron spectrum. Science 2017; 358:336-339. [DOI: 10.1126/science.aao1905] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/29/2017] [Indexed: 11/02/2022]
Affiliation(s)
- Jessalyn A. DeVine
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | | | - Benjamin Laws
- Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia
| | - Jing Chang
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610067, China
| | - Mark C. Babin
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
| | - Garikoitz Balerdi
- Departmento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid (Unidad Asociada I+D+I CSIC), 28040 Madrid, Spain
| | - Changjian Xie
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | | | - W. Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - David R. Yarkony
- Department of Chemistry, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Robert W. Field
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Stephen T. Gibson
- Research School of Physics and Engineering, Australian National University, Canberra, ACT 2601, Australia
| | - Jianyi Ma
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610067, China
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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10
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Lauzin C, Gans B, Merkt F. High-resolution photoelectron-spectroscopic investigation of the H 2O + cation in its electronic state. Mol Phys 2016. [DOI: 10.1080/00268976.2016.1231352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- C. Lauzin
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
- Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | - B. Gans
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
- Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - F. Merkt
- Physical Chemistry Laboratory, ETH Zürich, Zürich, Switzerland
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11
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Germann M, Willitsch S. Fine- and hyperfine-structure effects in molecular photoionization. I. General theory and direct photoionization. J Chem Phys 2016; 145:044314. [DOI: 10.1063/1.4955301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Matthias Germann
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
| | - Stefan Willitsch
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
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12
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Beyer M, Merkt F. Observation and Calculation of the Quasibound Rovibrational Levels of the Electronic Ground State of H2+. PHYSICAL REVIEW LETTERS 2016; 116:093001. [PMID: 26991172 DOI: 10.1103/physrevlett.116.093001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Indexed: 06/05/2023]
Abstract
Although the existence of quasibound rotational levels of the X^{+} ^{2}Σ_{g}^{+} ground state of H_{2}^{+} was predicted a long time ago, these states have never been observed. Calculated positions and widths of quasibound rotational levels located close to the top of the centrifugal barriers have not been reported either. Given the role that such states play in the recombination of H(1s) and H^{+} to form H_{2}^{+}, this lack of data may be regarded as one of the largest unknown aspects of this otherwise accurately known fundamental molecular cation. We present measurements of the positions and widths of the lowest-lying quasibound rotational levels of H_{2}^{+} and compare the experimental results with the positions and widths we calculate using a potential model for the X^{+} state of H_{2}^{+} which includes adiabatic, nonadiabatic, relativistic, and radiative corrections to the Born-Oppenheimer approximation.
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Affiliation(s)
- Maximilian Beyer
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
| | - Frédéric Merkt
- Laboratorium für Physikalische Chemie, ETH Zürich, 8093 Zürich, Switzerland
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13
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Lu Z, Gao H, Xu YT, Yang L, Lam CS, Benitez Y, Ng CY. High-Resolution Threshold Photoelectron Spectroscopy by Vacuum Ultraviolet Laser Velocity-Map-Imaging Method. CHINESE J CHEM PHYS 2016. [DOI: 10.1063/1674-0068/29/cjcp1512247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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14
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Lauzin C, Jacovella U, Merkt F. Threshold ionization spectroscopy of H 2O, HDO and D 2O and low-lying vibrational levels of HDO +and D 2O +. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1049971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Holzmeier F, Lang M, Fischer I, Tang X, Cunha de Miranda B, Romanzin C, Alcaraz C, Hemberger P. Threshold photoelectron spectroscopy of unstable N-containing compounds: Resolution of ΔK subbands in HNCO+ and vibrational resolution in NCO+. J Chem Phys 2015; 142:184306. [DOI: 10.1063/1.4920951] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Fabian Holzmeier
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Melanie Lang
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Ingo Fischer
- Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Xiaofeng Tang
- Synchrotron SOLEIL, l’Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France
| | - Barbara Cunha de Miranda
- Laboratoire de Chimie-Physique, UMR 8000 CNRS and Université Paris-Sud 11, F-91405 Orsay Cedex, France
| | - Claire Romanzin
- Laboratoire de Chimie-Physique, UMR 8000 CNRS and Université Paris-Sud 11, F-91405 Orsay Cedex, France
| | - Christian Alcaraz
- Laboratoire de Chimie-Physique, UMR 8000 CNRS and Université Paris-Sud 11, F-91405 Orsay Cedex, France
| | - Patrick Hemberger
- Molecular Dynamics Group, Paul Scherrer Institute (PSI), CH-5232 Villigen, Switzerland
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16
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Jacovella U, Gans B, Merkt F. Internal rotation, spin–orbit coupling, and low-frequency vibrations in the ground state of CH3–CC–CH+3and CD3–CC–CD+3. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1005708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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17
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Holzmeier F, Lang M, Fischer I, Hemberger P, Garcia GA, Tang X, Loison JC. Assignment of high-lying bending mode levels in the threshold photoelectron spectrum of NH2: a comparison between pyrolysis and fluorine-atom abstraction radical sources. Phys Chem Chem Phys 2015; 17:19507-14. [DOI: 10.1039/c5cp02964c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The bending mode progression in the photoelectron spectrum of NH2 was observed and assigned up to υ2+ ≤ 5 and Ka+ ≤ 3.
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Affiliation(s)
- F. Holzmeier
- Institute of Physical and Theoretical Chemistry
- University of Würzburg
- D-97074 Würzburg
- Germany
| | - M. Lang
- Institute of Physical and Theoretical Chemistry
- University of Würzburg
- D-97074 Würzburg
- Germany
| | - I. Fischer
- Institute of Physical and Theoretical Chemistry
- University of Würzburg
- D-97074 Würzburg
- Germany
| | - P. Hemberger
- Molecular Dynamics Group
- Paul Scherrer Institut CH-5232 Villigen
- Switzerland
| | | | - X. Tang
- Synchrotron SOLEIL
- 91192 Gif sur Yvette
- France
| | - J.-C. Loison
- ISM
- Université Bordeaux 1
- CNRS
- 33405 Talence Cedex
- France
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18
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Vasilatou K, Michaud JM, Baykusheva D, Grassi G, Merkt F. The cyclopropene radical cation: rovibrational level structure at low energies from high-resolution photoelectron spectra. J Chem Phys 2014; 141:064317. [PMID: 25134581 DOI: 10.1063/1.4890744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The cyclopropene radical cation (c-C3H₄⁺) is an important but poorly characterized three-membered-ring hydrocarbon. We report on a measurement of the high-resolution photoelectron and photoionization spectra of cyclopropene and several deuterated isotopomers, from which we have determined the rovibrational energy level structure of the X⁺ (2)B2 ground electronic state of c-C3H₄⁺ at low energies for the first time. The synthesis of the partially deuterated isotopomers always resulted in mixtures of several isotopomers, differing in their number of D atoms and in the location of these atoms, so that the photoelectron spectra of deuterated samples are superpositions of the spectra of several isotopomers. The rotationally resolved spectra indicate a C(2v)-symmetric R0 structure for the ground electronic state of c-C3H₄⁺. Two vibrational modes of c-C3H₄⁺ are found to have vibrational wave numbers below 300 cm(-1), which is surprising for such a small cyclic hydrocarbon. The analysis of the isotopic shifts of the vibrational levels enabled the assignment of the lowest-frequency mode (fundamental wave number of ≈110 cm(-1) in c-C3H₄⁺) to the CH2 torsional mode (ν₈⁺, A2 symmetry) and of the second-lowest-frequency mode (≈210 cm(-1) in c-C3H₄⁺) to a mode combining a CH out-of-plane with a CH2 rocking motion (ν₁₅⁺, B2 symmetry). The potential energy along the CH2 torsional coordinate is flat near the equilibrium structure and leads to a pronounced anharmonicity.
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Affiliation(s)
- K Vasilatou
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - J M Michaud
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - D Baykusheva
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - G Grassi
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
| | - F Merkt
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
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19
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Xu Y, Xiong B, Chang YC, Ng CY. The translational, rotational, and vibrational energy effects on the chemical reactivity of water cation H2O+(X 2B1) in the collision with deuterium molecule D2. J Chem Phys 2013; 139:024203. [DOI: 10.1063/1.4812774] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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20
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Goez M, Kerzig C. Counterintuitive Influence of Protonation on Radical-Anion Photoionization. Angew Chem Int Ed Engl 2012; 51:12606-8. [DOI: 10.1002/anie.201206605] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 09/18/2012] [Indexed: 11/11/2022]
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21
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Gao H, Xu Y, Yang L, Lam CS, Wang H, Zhou J, Ng CY. High-resolution threshold photoelectron study of the propargyl radical by the vacuum ultraviolet laser velocity-map imaging method. J Chem Phys 2011; 135:224304. [DOI: 10.1063/1.3664864] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Wu G, Hockett P, Stolow A. Time-resolved photoelectron spectroscopy: from wavepackets to observables. Phys Chem Chem Phys 2011; 13:18447-67. [PMID: 21947027 DOI: 10.1039/c1cp22031d] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Time-resolved photoelectron spectroscopy (TRPES) is a powerful tool for the study of intramolecular dynamics, particularly excited state non-adiabatic dynamics in polyatomic molecules. Depending on the problem at hand, different levels of TRPES measurements can be performed: time-resolved photoelectron yield; time- and energy-resolved photoelectron yield; time-, energy-, and angle-resolved photoelectron yield. In this pedagogical overview, a conceptual framework for time-resolved photoionization measurements is presented, together with discussion of relevant theory for the different aspects of TRPES. Simple models are used to illustrate the theory, and key concepts are further amplified by experimental examples. These examples are chosen to show the application of TRPES to the investigation of a range of problems in the excited state dynamics of molecules: from the simplest vibrational wavepacket on a single potential energy surface; to disentangling intrinsically coupled electronic and nuclear motions; to identifying the electronic character of the intermediate states involved in non-adiabatic dynamics by angle-resolved measurements in the molecular frame, the most complete measurement.
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Affiliation(s)
- Guorong Wu
- Steacie Institute for Molecular Sciences, National Research Council, 100 Sussex Drive, Ottawa, Ontario K1A 0R6, Canada
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Grütter M, Merkt F. Photoelectron spectroscopic study of the E ⊗ e Jahn–Teller effect in the presence of a tunable spin–orbit interaction. II. Rovibronic analysis of the2E ground state of CH3CI+. Mol Phys 2011. [DOI: 10.1080/00268976.2011.609143] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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24
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Merkt F, Signorell R, Palm H, Osterwalder A, Sommavilla M. Towards resolving the hyperfine structure in ions by photoelectron spectroscopy. Mol Phys 2011. [DOI: 10.1080/00268979809483237] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- F. Merkt
- a Laboratorium fur Physikalische Chemie , ETH-Zurich , Zurich , Switzerland
| | - R. Signorell
- a Laboratorium fur Physikalische Chemie , ETH-Zurich , Zurich , Switzerland
| | - H. Palm
- a Laboratorium fur Physikalische Chemie , ETH-Zurich , Zurich , Switzerland
| | - A. Osterwalder
- a Laboratorium fur Physikalische Chemie , ETH-Zurich , Zurich , Switzerland
| | - M. Sommavilla
- a Laboratorium fur Physikalische Chemie , ETH-Zurich , Zurich , Switzerland
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25
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Grütter M, Michaud JM, Merkt F. Photoelectron spectroscopic study of the E⊗e Jahn–Teller effect in the presence of a tunable spin–orbit interaction. I. Photoionization dynamics of methyl iodide and rotational fine structure of CH3I+and CD3I+. J Chem Phys 2011; 134:054308. [DOI: 10.1063/1.3547548] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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26
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Hollenstein U, Merkt F, Meyer L, Seiler R, Softley TP, Willitsch S. Rovibronic photoionization dynamics of ammonia isotopomers. Mol Phys 2010. [DOI: 10.1080/00268970701429889] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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27
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Ford MS, Müller-Dethlefs K, Kitajima M, Tanaka H, Tamenori Y, De Fanis A, Ueda K. Rotational Analysis for the Doppler-Free Photoelectron Spectrum of Water Using the Spectator Model. J Phys Chem A 2010; 114:11133-8. [DOI: 10.1021/jp102496n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | | | - Kyoshi Ueda
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan
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28
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Hockett P, Staniforth M, Reid KL. Photoionization Dynamics of Ammonia (B1E′′): Dependence on Ionizing Photon Energy and Initial Vibrational Level. J Phys Chem A 2010; 114:11330-6. [DOI: 10.1021/jp104623m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paul Hockett
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Michael Staniforth
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
| | - Katharine L. Reid
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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29
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Vasilatou K, Schäfer M, Merkt F. The Rotational Structure of the Origin Band of the Pulsed-Field-Ionization, Zero-Kinetic-Energy Photoelectron Spectra of Propene-h6 and Propene-d6. J Phys Chem A 2010; 114:11085-90. [DOI: 10.1021/jp101929d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. Vasilatou
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8092 Zürich, Switzerland
| | - M. Schäfer
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8092 Zürich, Switzerland
| | - F. Merkt
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8092 Zürich, Switzerland
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30
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Hockett P, Staniforth M, Reid KL. Photoelectron angular distributions from rotationally state-selected NH3(B1E′′): dependence on ion rotational state and polarization geometry. Mol Phys 2010. [DOI: 10.1080/00268971003639266] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Vasilatou K, Hollenstein U, Merkt F. Structure of the low-lying electronic states of from rotationally resolved photoelectron spectra. Mol Phys 2010. [DOI: 10.1080/00268970903567296] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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32
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Duggan L, Raunhardt M, Schäfer M, Hollenstein U, Softley T, Merkt F. PFI-ZEKE photoelectron and high resolution photoionization spectra of ND3with MQDT simulations. Mol Phys 2010. [DOI: 10.1080/00268971003649315] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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33
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Grütter M, Wörner HJ, Merkt F. Rovibronic analysis of the Jahn-Teller effect in CH2D2(+) at low energies. J Chem Phys 2009; 131:024309. [PMID: 19603993 DOI: 10.1063/1.3157210] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The Jahn-Teller effect in the ground state of CH(2)D(2)(+) has been studied by pulsed-field-ionization zero-kinetic-energy photoelectron spectroscopy. The lowest three bands have been assigned to the three isomers CH([l])H([l])D(s)D(s)(+), CH([l])H(s)D([l])D(s)(+), and CH(s)H(s)D([l])D([l])(+), in which the deuterium atoms are attached to the central carbon atom by two short bonds, one short and one long bond, and two long bonds, respectively, and which have different zero-point vibrational energies. Whereas CH([l])H([l])D(s)D(s)(+) and CH(s)H(s)D([l])D([l])(+) can each be described by a single structure with C(2v) symmetry, CH([l])H(s)D([l])D(s)(+) corresponds to four equivalent C(1) structures that interconvert by tunneling. The rotational structure of these three bands is compared with predictions made on the basis of a tunneling Hamiltonian combined with a rotational Hamiltonian that incorporates the effects of the large-amplitude tunneling motion. The zero-point energies of CH([l])H(s)D([l])D(s)(+) and CH(s)H(s)D([l])D([l])(+) relative to that of CH([l])H([l])D(s)D(s)(+) are Delta = 123.6(5) cm(-1) and Delta(') = 243.2(5) cm(-1), respectively, and the tunneling matrix element sigma coupling the four C(2v) equilibrium structures of CH([l])H(s)D([l])D(s)(+) is -1.7(4) cm(-1).
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Affiliation(s)
- M Grütter
- Laboratorium für Physikalische Chemie, ETH Zürich, CH-8093 Zurich, Switzerland
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34
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Gasser M, Schulenburg AM, Dietiker PM, Bach A, Merkt F, Chen P. Single-photon and resonance-enhanced multiphoton threshold ionization of the allyl radical. J Chem Phys 2009; 131:014304. [DOI: 10.1063/1.3157185] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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35
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Hockett P, Staniforth M, Reid KL, Townsend D. Rotationally resolved photoelectron angular distributions from a nonlinear polyatomic molecule. PHYSICAL REVIEW LETTERS 2009; 102:253002. [PMID: 19659072 DOI: 10.1103/physrevlett.102.253002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Indexed: 05/28/2023]
Abstract
We present, for the first time, rotationally resolved photoelectron images resulting from the ionization of a polyatomic molecule. Photoelectron angular distributions pertaining to the formation of individual rotational levels of NH3+ have been extracted from the images and analyzed to enable a complete determination of the radial dipole matrix elements and relative phases that describe the ionization dynamics. This determination leads to the deduction of significantly different dynamics from those extracted in previous studies which lacked either angular information or rotational resolution.
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Affiliation(s)
- Paul Hockett
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, United Kingdom
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36
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Schulenburg AM, Merkt F. Rotationally resolved photoelectron spectroscopic study of the Jahn–Teller effect in allene. J Chem Phys 2009; 130:034308. [DOI: 10.1063/1.3056385] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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37
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Bae YJ, Kim MS. Photodissociation spectroscopy of CD3I+ generated by mass-analyzed threshold ionization for structure determination. Chemphyschem 2009; 9:1709-14. [PMID: 18613197 DOI: 10.1002/cphc.200800207] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A method is devised better to resolve the subbands of the ground vibronic band in the mass-analyzed threshold ionization (MATI) spectrum of CD(3)I. By selective photodissociation of CD(3)I(+) in these subbands, high-resolution spectra for the A(2)A(1)<--X(2)E(3/2) transition are recorded. Spectral analysis confirms our previous suggestion that these subbands are due to cations in different rotational K states; this demonstrates the capability of MATI to generate rovibronically selected ion beams. By using the rotational constants of CH(3)I(+) and CD(3)I(+) obtained by spectral analysis, the zero-point-level geometries of the cations in the X(2)E(3/2) and A(2)A(1) states are determined. To the best of our knowledge, this is the first time that the capability of MATI-PD to determine the geometry of a gas-phase polyatomic cation in an excited electronic state is demonstrated.
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Affiliation(s)
- Yong Jin Bae
- Department of Chemistry, Seoul National University, Seoul 157-742, Korea
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38
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Stolow A, Underwood JG. Time-Resolved Photoelectron Spectroscopy of Nonadiabatic Dynamics in Polyatomic Molecules. ADVANCES IN CHEMICAL PHYSICS 2008. [DOI: 10.1002/9780470259498.ch6] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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39
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Bae YJ, Kim MS. Rotational state selection of a CH3I+ ion beam using vacuum ultraviolet-mass-analyzed threshold ionization spectroscopy: characterization using photodissociation spectroscopy. J Chem Phys 2008; 128:124324. [PMID: 18376936 DOI: 10.1063/1.2884340] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The A(2)A(1)<--X(2)E(3/2) transition of CH(3)I(+) was investigated by photodissociation (PD) of the cation generated by one-photon mass-analyzed threshold ionization (MATI). Compared to the PD spectrum obtained by excitation of the cation in the main 0-0 band in the MATI spectrum, those obtained by excitation of the cations in the satellite structures showed substantially simplified rotational structures for nondegenerate vibronic bands. Spectral simplification occurred because each satellite consisted mostly of cations with one K quantum number. Spectroscopic constants in the ground vibronic state and in the 2(1)3(5), 2(1)3(8), 3(9), and 3(13) nondegenerate vibrational states in A(2)A(1) were determined via spectral fitting. Also, those in the 2(1)3(n)6(1) (n=1?) degenerate state, which had been reported previously, was improved. The K quantum number in each satellite determined by the present high resolution study was compatible with the prediction by the symmetry selection rule for photoionization. That is, the K quantum number of the ion core in high Rydberg states accessed by one-photon excitation was found to be conserved upon pulsed field ionization. This work demonstrates generation of mass-selected, vibronically selected, and K-selected ion beam by one-photon MATI.
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Affiliation(s)
- Yong Jin Bae
- Department of Chemistry, Seoul National University, Seoul 151-742, South Korea
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40
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Xing X, Bahng MK, Reed B, Lam CS, Lau KC, Ng CY. Rovibrationally selected and resolved pulsed field ionization-photoelectron study of propyne: Ionization energy and spin-orbit interaction in propyne cation. J Chem Phys 2008; 128:094311. [DOI: 10.1063/1.2836429] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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Lee M, Bae YJ, Kim MS. K selection in one-photon mass-analyzed threshold ionization of CH3I and CD3I to the X2E3/2 state cations. J Chem Phys 2008; 128:044310. [PMID: 18247952 DOI: 10.1063/1.2823032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
One-photon mass-analyzed threshold ionization (MATI) spectra for the X (2)E(3/2) states of CH(3)I(+) and CD(3)I(+) were measured using vacuum ultraviolet radiation generated by four-wave mixing in Kr. Spin-orbit density functional theory calculations at the B3LYP/aug-cc-pVTZ level and spin-orbit/Jahn-Teller calculations were made to aid vibrational assignment. Each vibrational band consisted of several peaks due to different DeltaK transitions, which could be assigned by using molecular parameters determined in the previous high resolution photodissociation spectroscopic study. Possibility of generating mass-selected, vibronically selected and K-selected ion beam with decent intensity by one-photon MATI was demonstrated. The ionization energies to the X (2)E(3/2) states of CH(3)I(+) and CD(3)I(+) corrected for the rotational contribution were 9.5386+/-0.0006 and 9.5415+/-0.0006 eV, respectively.
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Affiliation(s)
- Mina Lee
- Department of Chemistry, Seoul National University, Seoul 151-742, Korea
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42
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Hockett P, Reid KL. Complete determination of the photoionization dynamics of a polyatomic molecule. II. Determination of radial dipole matrix elements and phases from experimental photoelectron angular distributions from ÃAu1 acetylene. J Chem Phys 2007; 127:154308. [DOI: 10.1063/1.2790443] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Wörner HJ, Merkt F. Diradicals, antiaromaticity, and the pseudo-Jahn-Teller effect: Electronic and rovibronic structures of the cyclopentadienyl cation. J Chem Phys 2007; 127:034303. [PMID: 17655439 DOI: 10.1063/1.2748049] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The electronic and rovibronic structures of the cyclopentadienyl cation (C(5)H(5) (+)) and its fully deuterated isotopomer (C(5)D(5) (+)) have been investigated by pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectroscopy and ab initio calculations. The vibronic structure in the two lowest electronic states of the cation has been determined using single-photon ionization from the X (2)E(1) (") ground neutral state and 1+1(') resonant two-photon ionization via several vibrational levels of the A (2)A(2) (") excited state. The cyclopentadienyl cation possesses a triplet ground electronic state (X(+) (3)A(2) (')) of D(5h) equilibrium geometry and a first excited singlet state (a(+) (1)E(2) (')) distorted by a pseudo-Jahn-Teller effect. A complete analysis of the Emultiply sign in circlee Jahn-Teller effect and of the (A+E)multiply sign in circlee pseudo-Jahn-Teller effect in the a(+) (1)E(2) (') state has been performed. This state is subject to a very weak linear Jahn-Teller effect and to an unusually strong pseudo-Jahn-Teller effect. Vibronic calculations have enabled us to partially assign the vibronic structure and determine the adiabatic singlet-triplet interval (1534+/-6 cm(-1)). The experimental spectra, a group-theoretical analysis of the vibronic coupling mechanisms, and ab initio calculations were used to establish the topology of the singlet potential energy surfaces and to characterize the pseudorotational motion of the cation on the lowest singlet potential energy surface. The analysis of the rovibronic photoionization dynamics in rotationally resolved spectra and the study of the variation of the intensity distribution with the intermediate vibrational level show that a Herzberg-Teller mechanism is responsible for the observation of the forbidden a(+) (1)E(2) (')<--A (2)A(2) (") photoionizing transition.
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Affiliation(s)
- H J Wörner
- Laboratorium für Physikalische Chemie, ETH-Zürich, 8093 Zürich, Switzerland
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44
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Zhou J, Garand E, Eisfeld W, Neumark DM. Slow electron velocity-map imaging spectroscopy of the 1-propynyl radical. J Chem Phys 2007; 127:034304. [PMID: 17655440 DOI: 10.1063/1.2748399] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
High resolution photoelectron spectra of the 1-propynyl and 1-propynyl-d(3) anions acquired with slow electron velocity-map imaging are presented. The electron affinity is determined to be 2.7355+/-0.0010 eV for the 1-propynyl radical and 2.7300+/-0.0010 eV for 1-propynyl-d(3). Several vibronic transitions are observed and assigned using the isotopic shifts and results from ab initio calculations. Good agreement between experimental spectra and calculations suggests a C(3v) geometry for the 1-propynyl radical. No evidence is found for strong vibronic coupling between the ground electronic state and the low-lying first excited state.
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Affiliation(s)
- Jia Zhou
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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45
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Xing X, Reed B, Lau KC, Ng CY, Zhang X, Ellison GB. Vacuum ultraviolet laser pulsed field ionization-photoelectron study of allyl radical CH2CHCH2. J Chem Phys 2007; 126:171101. [PMID: 17492849 DOI: 10.1063/1.2737443] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The pulsed field ionization-photoelectron (PFI-PE) spectrum of allyl radical CH2CHCH2 (C3H5) in the energy range of 65 200-66 600 cm-1 has been measured using vacuum ultraviolet laser. Based on the simulation of the rotational structures resolved in the vibrational PFI-PE bands of C3H5+(X 1A1;0(0+) and nu7+=1), the ionization energies (IEs) of C3H5(X 2A2;0(0)) to form C3H5+(X 1A1;0(0+) and nu7+=1) are determined to be 65 584.6+/-2.0 cm-1 (8.131 46+/-0.000 25 eV) and 66 020.9+/-2.0 cm-1 (8.185 56+/-0.000 25 eV), respectively, where nu7+(a1) is the symmetric C-C-C bending mode of C3H5+(X 1A1). These values are compared to IE(C3H5) values obtained in previous experimental and high-level ab initio quantum theoretical studies.
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Affiliation(s)
- Xi Xing
- Department of Chemistry, University of California, Davis, Davis, California 95616
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46
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Softley TP. Applications of molecular Rydberg states in chemical dynamics and spectroscopy. INT REV PHYS CHEM 2007. [DOI: 10.1080/01442350310001652940] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- T. P. Softley
- a Department of Chemistry , Chemistry Research Laboratory, University of Oxford , Mansfield Rd, Oxford OX1 3TA, UK
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47
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Tang SJ, Chou YC, Lin JJM, Hsu YC. The bending vibrational levels of the acetylene cation: A case study of the Renner-Teller effect in a molecule with two degenerate bending vibrations. J Chem Phys 2006; 125:133201. [PMID: 17029448 DOI: 10.1063/1.2199827] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Forty three vibronic levels of C2H2+, X 2Pi u, with upsilon4 = 0-6, upsilon5 = 0-3, and K = 0-4, lying at energies of 0-3520 cm(-1) above the zero-point level, have been recorded at rotational resolution. These levels were observed by double resonance, using 1+1' two-color pulsed-field ionization zero-kinetic-energy photoelectron spectroscopy. The intermediate states were single rovibrational levels chosen from the A1Au, 4nu3 (K = 1-2), 5nu3 (K = 1), nu2+4nu3 (K = 0), and 47,206 cm(-1) (K = 1) levels of C2H2. Seven of the trans-bending levels of C2H2+ (upsilon4 = 0-3, K = 0-2) had been reported previously by Pratt et al. [J. Chem. Phys. 99, 6233 (1993)]; our results for these levels agree well with theirs. A full analysis has been carried out, including the Renner-Teller effect and the vibrational anharmonicity for both the trans- and cis-bending vibrations. The rotational structure of the lowest 16 vibronic levels (consisting of the complete set of levels with upsilon4 + upsilon5 < or = 2, except for the unobserved upper (2Pi u component of the 2nu4 overtone) could be fitted by least squares using 16 parameters to give an rms deviation of 0.21 cm(-1). The vibronic coupling parameter epsilon5 (about whose magnitude there has been controversy) was determined to be -0.0273(7). For the higher vibronic levels, an additional parameter, r45, was needed to allow for the Darling-Dennison resonance between the two bending manifolds. Almost all the observed levels of the upsilon4 + upsilon5 = 3 and 4 polyads (about half of the predicted number) could then be assigned. In a final fit to 39 vibronic levels with upsilon4 + upsilon5 < or = 5, an rms deviation of 0.34 cm(-1) was obtained using 20 parameters. An interesting finding is that Hund's spin-coupling cases (a) and (b) both occur in the Sigmau components of the nu4 + 2nu5 combination level. The ionization potential of C2H2 (from the lowest rotational level of the ground state to the lowest rotational level of the cation) is found to be 91,953.77 +/- 0.09 cm(-1) (3sigma).
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Affiliation(s)
- Sheunn-Jiun Tang
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan, Republic of China
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48
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Xing X, Bahng MK, Wang P, Lau KC, Baek SJ, Ng CY. Rovibrationally selected and resolved state-to-state photoionization of ethylene using the infrared-vacuum ultraviolet pulsed field ionization-photoelectron method. J Chem Phys 2006; 125:133304. [PMID: 17029457 DOI: 10.1063/1.2213261] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
By preparing ethylene [C2H4(X1Ag)] in selected rotational levels of the nu11(b1u), nu2+nu12(b1u), or nu9(b2u) vibrational state with infrared (IR) laser photoexcitation prior to vacuum ultraviolet (VUV) laser photoionization, we have recorded rotationally resolved pulsed field ionization-photoelectron (PFI-PE) spectra for C2H4+(X2B3u) in the energy region of 0-3000 cm(-1) above the ionization energy (IE) of C2H4(X1Ag). Here, nu2(ag), nu9(b2u), nu11(b1u), and nu12(b1u) represent the C-C stretching, CH2 stretching, CH2 stretching, and CH2 bending modes of C2H4(X1Ag), respectively. The fully rovibrationally resolved spectra have allowed unambiguous symmetry assignments of the observed vibrational bands, which in turn have provided valuable information on the photoionization dynamics of C2H4. The IR-VUV photoionization of C2H4(X1Ag) via the nu11(b1u) or nu2+nu12(b1u) vibrational states is found to predominantly produce vibrational states of C2H4+(X2B3u) with b1u symmetry, which cannot be observed in single-photon VUV-PFI-PE measurements of C2H4(X1Ag). The analysis of the observed IR-VUV-PFI-PE bands has provided the IE(C2H4) = 84,790.2(2) cm(-1) and accurate vibrational frequencies for the nu4+(au)[84.1(2) cm(-1)], nu12+(b1u)[1411.7(2) cm(-1)], nu4+ +nu12+(b1g)[1482.5(2) cm(-1)], nu2+(ag)[1488.3(2) cm(-1)], nu2+ + nu4+(au)[1559.2(2) cm(-1)], 2nu4+ + nu12 +(b1u)[1848.5(2) cm(-1)], 4nu4+ + nu12 +(b1u)[2558.8(2) cm(-1)], nu2+ + nu12 +(b1u)[2872.7(2) cm(-1)], and nu11+(b1u)[2978.7(2) cm(-1)] vibrational states of C2H4+(X2B3u), where nu4+ is the ion torsional state. The IE(C2H4) and the nu4+(au), nu2+(ag), and nu2+ + nu4+ (au) frequencies are in excellent accord with those obtained in previous single-photon VUV-PFI-PE measurements. The other ion vibrational frequencies represent new experimental determinations. We have also performed high-level ab initio anharmonic vibrational frequency calculations for C2H4(X1Ag) and C2H4+(X2B3u) at the CCSD(T)/aug-cc-pVQZ level for guidance in the assignment of the IR-VUV-PFI-PE spectra. All theoretical vibrational frequencies for the neutral and ion, except the ion torsional frequency, are found to agree with experimental vibrational frequencies to better than 1%.
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Affiliation(s)
- Xi Xing
- Department of Chemistry, University of California at Davis, Davis, California 95616, USA
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Schulenburg AM, Alcaraz C, Grassi G, Merkt F. Rovibrational photoionization dynamics of methyl and its isotopomers studied by high-resolution photoionization and photoelectron spectroscopy. J Chem Phys 2006; 125:104310. [PMID: 16999529 DOI: 10.1063/1.2348875] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
High-resolution photoionization and pulsed-field-ionization zero-kinetic-energy photoelectron spectra of CH(3), CH(2)D, CHD(2), and CD(3) have been recorded in the vicinity of the first adiabatic ionization threshold following single-photon excitation from the ground neutral state using a narrow-bandwidth vacuum-ultraviolet laser. The radicals were produced from the precursor molecules methyl-bromide, methyl-iodide, dimethyl-thioether, acetone, and nitromethane by 193 nm excimer photolysis in a quartz capillary and were subsequently cooled to a rotational temperature T(rot) approximately equal to 30 K in a supersonic expansion. Nitromethane was identified as a particularly suitable photolytic precursor of methyl for studies by photoionization and threshold photoelectron spectroscopy. Thanks to the cold rotational temperature reached in the supersonic expansion, the rotational structure of the threshold ionization spectra could be resolved, and the photoionization dynamics investigated. Rydberg series converging on excited rotational levels of CH(3) (+) could be observed in the range of principal quantum number n=30-50, and both rotational autoionization and predissociation were identified as decay processes in the threshold region. The observed photoionization transitions can be understood in the realm of an orbital model for direct ionization but the intensity distributions can only be fully accounted for if the rotational channel interactions mediated by the quadrupole of the cation are considered. Improved values of the adiabatic ionization thresholds were derived for all isotopomers [CH(3): 79 356.2(15) cm(-1), CH(2)D: 79 338.8(15) cm(-1), CHD(2): 79 319.1(15) cm(-1), and CD(3): 79 296.4(15) cm(-1)].
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Affiliation(s)
- A M Schulenburg
- Laboratorium für Physikalische Chemie, ETH-Zürich, CH-8093 Zürich, Switzerland
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Willitsch S, Jungen C, Merkt F. Bending energy level structure and quasilinearity of the X̃+B13 ground electronic state of NH2+. J Chem Phys 2006; 124:204312. [PMID: 16774337 DOI: 10.1063/1.2193519] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The bending level structure of the quasilinear X+ 3B1 ground electronic state of the amidogen cation NH2+ was studied by pulsed-field-ionization zero-kinetic-energy photoelectron spectroscopy using a near-infrared vacuum-ultraviolet two-photon ionization sequence via selected rovibronic levels of the A 2A1 state of NH2. The careful selection of the intermediate levels permitted to optimize the transition intensities to the lowest vibrational levels of the cation in the photoionization step and to overcome the low sensitivity of previously employed single-photon ionization schemes. For the first time, all bending levels of the cationic ground state with quantum numbers upsilon2,lin + < or =4, N+ < or =4, and /K+/ < or =2 could be observed, enabling a detailed characterization of the large-amplitude bending vibration. The rotational structure corresponds to that of an effectively linear molecule in all observed vibrational levels. The bending vibrational structure which shows marked deviations from a harmonic behavior was analyzed in terms of a semirigid bender model. The bending potential function was obtained from a fit to the experimental data. The height of the barrier at the linear geometry and the bond angle at the potential minimum were determined to be 231.8(22) cm(-1) and 152.54(4) degrees , respectively, and all bending levels are located above the maximum of the barrier.
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Affiliation(s)
- S Willitsch
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland and Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
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