1
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Carrick IJ, Fabijanczuk KC, Rong J, McLuckey SA. Tandem mass spectrometry using continuous-wave infrared multiphoton dissociation in an electrostatic linear ion trap. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2024; 38:e9698. [PMID: 38356088 DOI: 10.1002/rcm.9698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 02/16/2024]
Abstract
RATIONALE The electrostatic linear ion trap (ELIT) can be operated as a multi-reflection time-of-flight (MR-TOF) or Fourier transform (FT) mass analyzer. It has been shown to be capable of performing high-resolution mass analysis and high-resolution ion isolations. Although it has been used in charge-detection mass spectrometry (CDMS), it has not been widely used as a conventional mass spectrometer for ensemble measurements of ions, or for tandem mass spectrometer. The advantages of tandem mass spectrometer with high-resolution ion isolations in the ELIT have thus not been fully exploited. METHODS A homebuilt ELIT was modified with BaF2 viewports to facilitate transmission of a laser beam at the turnaround point of the second ion mirror in the ELIT. Fragmentation that occurs at the turnaround point of these ion mirrors should result in minimal energy partitioning due to the low kinetic energy of ions at these points. The laser was allowed to irradiate ions for a period of many oscillations in the ELIT. RESULTS Due to the low energy absorption of gas-phase ions during each oscillation in the ELIT, fragmentation was found to occur over a range of oscillations in the ELIT generating a homogeneous ion beam. A mirror-switching pulse is shown to create time-varying perturbations in this beam that oscillate at the fragment ion characteristic frequencies and generate a time-domain signal. This was found to recover FT signal for protonated pYGGFL and pSGGFL precursor ions. CONCLUSIONS Fragmentation at the turnaround point of an ELIT by continuous-wave infrared multiphoton dissociation (cw-IRMPD) is demonstrated. In cases where laser power absorption is low and fragmentation occurs over many laps, a mirror-switching pulse may be used to recover varying time-domain signal. The combination of laser activation at the turnaround points and mirror-switching isolation allows for tandem MS in the ELIT.
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Affiliation(s)
- Ian J Carrick
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | | | - Jiayue Rong
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Scott A McLuckey
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
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2
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Krohn OA, Lewandowski HJ. Cold Ion-Molecule Reactions in the Extreme Environment of a Coulomb Crystal. J Phys Chem A 2024. [PMID: 38359783 DOI: 10.1021/acs.jpca.3c07546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Coulomb crystals provide a unique environment in which to study ion-neutral gas-phase reactions. In these cold, trapped ensembles, we are able to study the kinetics and dynamics of small molecular systems. These measurements have connections to chemistry in the Interstellar Medium (ISM) and planetary atmospheres. This Feature Article will describe recent work in our laboratory that uses Coulomb crystals to study translationally cold, ion-neutral reactions. We provide a description of how the various affordances of our experimental system allow for detailed studies of the reaction mechanisms and the corresponding products. In particular, we will describe quantum-state resolved reactions, isomer-dependent reactions, and reactions with a rarely studied, astrophysically relevant ion, CCl+.
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Affiliation(s)
- O A Krohn
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - H J Lewandowski
- JILA and the Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
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3
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Zhang YR, Yuan DF, Wang LS. Probing Dipole-Bound States Using Photodetachment Spectroscopy and Resonant Photoelectron Imaging of Cryogenically Cooled Anions. J Phys Chem Lett 2023; 14:7368-7381. [PMID: 37565830 DOI: 10.1021/acs.jpclett.3c01994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Molecular anions with polar neutral cores can support highly diffuse dipole-bound states below their detachment thresholds due to the long-range charge-dipole interaction. Such nonvalence states constitute a special class of excited electronic states for anions and were observed in early photodetachment experiments to measure the electron affinities of organic radicals. Recent experimental advances, in particular, the ability to create cold anions using a cryogenically cooled Paul trap, have allowed the investigation of dipole-bound excited states at a new level. For the first time, the zero-point level of dipole-bound excited states can be observed via resonant two-photon detachment, and resonant photoelectron spectroscopy can be performed via the above-threshold vibrational levels (Feshbach resonances) of the dipole-bound states. This Perspective describes recent progress in the investigation of dipole-bound states in the authors' lab using an electrospray photoelectron spectroscopy apparatus equipped with a cryogenically cooled Paul trap and high-resolution photoelectron imaging.
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Affiliation(s)
- Yue-Rou Zhang
- 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
- Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026, China
| | - Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
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4
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Concina B, Bordas C. Thermionic Emission of Negative Ions of Molecules and Small Clusters as a Probe of Low-Energy Attachment. J Phys Chem A 2022; 126:7442-7451. [PMID: 36221803 DOI: 10.1021/acs.jpca.2c04530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have been studying the thermionic emission of negatively charged molecules and small clusters for more than a decade. The kinetic energy released distribution (KERD) of mass-selected negative ions has been measured with a velocity map imaging spectrometer. A comparison of the experimental KERD to detailed balance models provided information on the reverse process, namely, the electron attachment to the parent. The electron attachment to neutral systems (reverse process of the electron emission from anions) is usually described in a simplified way as a single electron capture in the framework of the classical Langevin model. Our measurements show that this approach is insufficient and that, in addition to the capture step, an intramolecular vibrational redistribution (IVR) step should be included. As far as multiply charged anions are concerned, the electron attachment to anions (reverse process of the electron emission from dianions) is strongly affected by the repulsive Coulomb barrier (RCB). Previous studies assumed a pure over-the-barrier process, which is in disagreement with our study. Indeed, electron emission is measured below the RCB, revealing significant thermal tunneling. In the present review, we summarize these works on singly and doubly charged anions in an attempt to present a unified view of the involved processes. It is worth noting that the detailed measurements of KERDs in the very low kinetic energy region (typically around 0.1 eV) have been made possible thanks to electron imaging methods, without which all of this work could never have been done, with time-resolution capabilities allowing the disentangling of direct and delayed electron emission.
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Affiliation(s)
- Bruno Concina
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622Villeurbanne, France
| | - Christian Bordas
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622Villeurbanne, France
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5
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Benitez Y, Nguyen TL, Parsons AJ, Stanton JF, Continetti RE. Probing the Exit Channel of the OH + CH 3OH → H 2O + CH 3O Reaction by Photodetachment of CH 3O -(H 2O). J Phys Chem Lett 2022; 13:142-148. [PMID: 34962408 DOI: 10.1021/acs.jpclett.1c03568] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Transition state dynamics of bimolecular reactions can be probed by photodetachment of a precursor anion when the Franck-Condon region of the corresponding neutral potential energy surface is near a saddle point. In this study, photodetachment of anions at m/z = 49 enabled investigation of the exit channel of the OH + CH3OH → H2O + CH3O reaction using photoelectron-photofragment coincidence spectroscopy. High-level coupled-cluster calculations of the stationary points on the anion surface show that the methoxide-water cluster CH3O-(H2O) is the stable minimum on the anion surface. Photodetachment at a 3.20 eV photon energy leads to long-lived H2O(CH3O) complexes and H2O + CH3O products consistent with both direct dissociative photodetachment and resonance mediated processes on the neutral surface. The partitioning of total kinetic energy in the system indicates that water stretch and bend excitation is induced in dissociative photodetachment and evidence for long-lived complexes consistent with vibrational Feshbach resonances is reported.
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Affiliation(s)
- Yanice Benitez
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Thanh Lam Nguyen
- Quantum Theory Project, Department of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Austin J Parsons
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - John F Stanton
- Quantum Theory Project, Department of Chemistry and Physics, University of Florida, Gainesville, Florida 32611, United States
| | - Robert E Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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6
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Benitez Y, Parsons AJ, Lunny KG, Continetti RE. Dissociative Photodetachment Dynamics of the OH -(C 2H 4) Anion Complex. J Phys Chem A 2021; 125:4540-4547. [PMID: 34030440 DOI: 10.1021/acs.jpca.1c01835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photoelectron-photofragment coincidence (PPC) measurements on OH-(C2H4) anions at a photon energy of 3.20 eV revealed stable and dissociative photodetachment product channels, OH-C2H4 + e- and OH + C2H4 + e-, respectively. The main product channel observed was dissociation to the reactants (>67%), OH + C2H4 (v = 0, 1, 2) + e-, where vibrational excitation in the C-H stretching modes of the C2H4 photofragments corresponds to a minor channel. The low kinetic energy release (KER) of the dissociating fragments is consistent with weak repulsion between the OH + C2H4 reactants near the transition state as well as the partitioning of energy into rotation of the dissociation products. An impulsive model was used to account for rotational energy partitioning in the dissociative photodetachment (DPD) process and showed good agreement with the experimental results. The low KER of the dissociating fragments and the similarities in the photoelectron spectra between stable and dissociative events support a mechanism involving the van der Waals complex formed upon photodetachment of OH-(C2H4) as an intermediate in the dominant OH + C2H4 + e- dissociative channel.
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Affiliation(s)
- Yanice Benitez
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Austin J Parsons
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Katharine G Lunny
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
| | - Robert E Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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7
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Hua ZF, Zhao YX, Li YQ, Hu GM, Chen Y, Zhao DF. Ion-neutral photofragment coincidence imaging of photodissociation dynamics of ionic species. CHINESE J CHEM PHYS 2021. [DOI: 10.1063/1674-0068/cjcp2007119] [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]
Affiliation(s)
- Ze-feng Hua
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yun-xiao Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - You-qing Li
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Gao-ming Hu
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yang Chen
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
| | - Dong-feng Zhao
- CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China
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8
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Gibbard JA, Continetti RE. Photoelectron photofragment coincidence spectroscopy of carboxylates. RSC Adv 2021; 11:34250-34261. [PMID: 35497305 PMCID: PMC9042398 DOI: 10.1039/d1ra06340e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 10/06/2021] [Indexed: 12/23/2022] Open
Abstract
Photoelectron–photofragment coincidence (PPC) spectroscopy is a powerful technique for studying the decarboxylation dynamics of carboxyl radicals. Measurement of photoelectron and photofragment kinetic energies in coincidence provides a kinematically complete measure of the dissociative photodetachment (DPD) dynamics of carboxylate anions. PPC spectroscopy studies of methanoate, ethanoate, propanoate, 2-butenoate, benzoate, p-coumarate and the oxalate monoanion are reviewed. All of the systems studied undergo decarboxylation via a two-body DPD channel i.e., driven by the thermodynamic stability of CO2. Additionally, decarboxylation is observed via a three-body ionic photodissociation channel for p-coumarate. In some cases photodetachment also results in a stable carboxyl radical (RCO2). The branching ratio for DPD, the threshold detachment energy and the peak of the kinetic energy release spectrum are compared for different carboxylates, as a probe of the character of the potential energy landscape in the Franck–Condon region. Photoelectron photofragment coincidence spectroscopy studies of a range of carboxylate anions are reviewed, revealing details of the decarboxylation dynamics of carboxyl radicals.![]()
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Affiliation(s)
- J. A. Gibbard
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr, La Jolla, Ca, 92093-0340, USA
| | - R. E. Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Dr, La Jolla, Ca, 92093-0340, USA
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9
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Benitez Y, Lu D, Lunny KG, Li J, Guo H, Continetti RE. Photoelectron–Photofragment Coincidence Studies on the Dissociation Dynamics of the OH–CH4 Complex. J Phys Chem A 2019; 123:4825-4833. [DOI: 10.1021/acs.jpca.9b02441] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yanice Benitez
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Dandan Lu
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China
| | - Katharine G. Lunny
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Jun Li
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China
- Institut für Physikalische Chemie, Theoretische Chemie, Universität Göttingen, Göttingen 37077, Germany
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131, United States
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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10
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Shen BB, Lunny KG, Benitez Y, Continetti RE. Photoelectron-Photofragment Coincidence Spectroscopy With Ions Prepared in a Cryogenic Octopole Accumulation Trap: Collisional Excitation and Buffer Gas Cooling. Front Chem 2019; 7:295. [PMID: 31114785 PMCID: PMC6503059 DOI: 10.3389/fchem.2019.00295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Accepted: 04/10/2019] [Indexed: 11/17/2022] Open
Abstract
A cryogenic octopole accumulation trap (COAT) has been coupled to a photoelectron-photofragment coincidence (PPC) spectrometer allowing for improved control over anion vibrational excitation. The anions are heated and cooled via collisions with buffer gas <17 K. Shorter trapping times (500 μs) prevent thermalization and result in anions with high internal excitation while longer trapping times (80 ms) at cryogenic temperatures thermalize the ions to the temperature of the buffer gas. The capabilities of the COAT are demonstrated using PPC spectroscopy ofO 3 - at 388 nm (Ehν = 3.20 eV). Cooling the precursor anions with COAT resulted in the elimination of the autodetachment of vibrationally excitedO 2 - produced by the photodissociationO 3 - + hν → O +O 2 - (v ≥ 4). Under heating conditions, a lower limit temperature for the anions was determined to be 1,500 K through Franck-Condon simulations of the photodetachment spectrum ofO 3 - , considering a significant fraction of the ions undergo photodissociation in competition with photodetachment. The ability to cool or heat ions by varying ion injection and trapping duration in COAT provides a new flexibility for studying the spectroscopy of cold ions as well as thermally activated processes.
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Affiliation(s)
| | | | | | - Robert E. Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, CA, United States
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11
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Menk S, Bertier P, Enomoto Y, Masunaga T, Majima T, Nakano Y, Azuma T. A cryogenic linear ion trap beamline for providing keV ion bunches. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:113110. [PMID: 30501304 DOI: 10.1063/1.5051044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 10/23/2018] [Indexed: 06/09/2023]
Abstract
A new cryogenic linear ion trap beamline has been constructed and commissioned, which serves to inject cold molecular and cluster ions into the RIKEN cryogenic electrostatic ring (RICE). Ions are created with an electrospray ion source, and a quadrupole mass filter is used for mass-selection prior to trap injection. The radio frequency octupole ion trap can be continuously loaded with ions and features a fast ion extraction mode to create short ion bunches with tens of μs duration. We report here on the simulations and development of the ion trap beamline and validate performance with the moderately heavy molecular cation methylene blue. Characterization of the novel trap design with additional wedge-shaped electrodes was carried out, which includes the determination of the temporal and spatial shape of the ion bunch and the total number of ions after extraction. Finally, these ion bunches are synchronized with the switching of a pulsed high-voltage acceleration device downstream of the trap, where the ions obtain a kinetic energy of up to 20 keV. The preparation and control of the keV ion beam are demonstrated for the ion injection into RICE.
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Affiliation(s)
- S Menk
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - P Bertier
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - Y Enomoto
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - T Masunaga
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - T Majima
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Y Nakano
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
| | - T Azuma
- AMO Physics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan
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12
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Zhang J, Xie H, Li G, Kong X, Fan H, Jiang L. Photoelectron Velocity-Map Imaging and Theoretical Studies of Heterotrinuclear Metal Carbonyls V 2Ni(CO) n– ( n = 6–10). J Phys Chem A 2018; 122:53-59. [DOI: 10.1021/acs.jpca.7b09230] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jumei Zhang
- State
Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation
Center of Chemistry for Energy and Materials (iChEM), Dalian Institute
of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan
Road, Dalian 116023, China
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Hua Xie
- State
Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation
Center of Chemistry for Energy and Materials (iChEM), Dalian Institute
of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan
Road, Dalian 116023, China
| | - Gang Li
- State
Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation
Center of Chemistry for Energy and Materials (iChEM), Dalian Institute
of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan
Road, Dalian 116023, China
| | - Xiangtao Kong
- State
Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation
Center of Chemistry for Energy and Materials (iChEM), Dalian Institute
of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan
Road, Dalian 116023, China
| | - Hongjun Fan
- State
Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation
Center of Chemistry for Energy and Materials (iChEM), Dalian Institute
of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan
Road, Dalian 116023, China
| | - Ling Jiang
- State
Key Laboratory of Molecular Reaction Dynamics, Collaborative Innovation
Center of Chemistry for Energy and Materials (iChEM), Dalian Institute
of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan
Road, Dalian 116023, China
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13
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Shahi A, Albeck Y, Strasser D. Simultaneous 3D coincidence imaging of cationic, anionic, and neutral photo-fragments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:013303. [PMID: 29390661 DOI: 10.1063/1.5004523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We present the design and simulations of a 3D coincidence imaging spectrometer for fast beam photofragmentation experiments. Coincidence detection of cationic, neutral, and anionic fragments involves spectrometer aberrations that are successfully corrected by an analytical model combined with exact numerical simulations. The spectrometer performance is experimentally demonstrated by characterization of four different channels of intense 800 nm pulse interaction with F2-: F- + F photodissociation, F + F dissociative photodetachment, F+ + F dissociative ionization, and F+ + F+ coulomb explosion. Improved measurement of F2- photodissociation with a 400 nm photon allows a better determination of the F2- anion dissociation energy, 1.256 ± 0.005 eV.
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Affiliation(s)
- Abhishek Shahi
- Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Yishai Albeck
- Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Daniel Strasser
- Institute of Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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14
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Ray AW, Ma J, Otto R, Li J, Guo H, Continetti RE. Effects of vibrational excitation on the F + H 2O → HF + OH reaction: dissociative photodetachment of overtone-excited [F-H-OH] . Chem Sci 2017; 8:7821-7833. [PMID: 29163919 PMCID: PMC5674243 DOI: 10.1039/c7sc03364h] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/23/2017] [Indexed: 11/21/2022] Open
Abstract
Photodetaching vibrationally excited FH2O– channels energy into the reaction coordinate of the F + H2O reaction, as shown in this joint experimental-theoretical study.
The reaction F + H2O → HF + OH is a four-atom system that provides an important benchmark for reaction dynamics. Hydrogen atom transfer at the transition state for this reaction is expected to exhibit a strong dependence on reactant vibrational excitation. In the present study, the vibrational effects are examined by photodetachment of vibrationally excited F–(H2O) precursor anions using photoelectron-photofragment coincidence (PPC) spectroscopy and compared with full six-dimensional quantum dynamical calculations on ab initio potential energy surfaces. Prior to photodetachment at hνUV = 4.80 eV, the overtone of the ionic hydrogen bond mode in the precursor F–(H2O), 2νIHB at 2885 cm–1, was excited using a tunable IR laser. Experiment and theory show that vibrational energy in the anion can be effectively carried away by the photoelectron upon a Franck–Condon photodetachment, and also show evidence for an increase of branching into the F + H2O reactant channel. The experimental results suggest a greater role for product rotational excitation than theory. Improved potential energy surfaces and longer wavepacket propagation times would be helpful to further examine the nature of the discrepancy.
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Affiliation(s)
- Amelia W Ray
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0340 , USA .
| | - Jianyi Ma
- Institute of Atomic and Molecular Physics , Sichuan University , Chengdu , Sichuan 610065 , China .
| | - Rico Otto
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0340 , USA .
| | - Jun Li
- School of Chemistry and Chemical Engineering , Chongqing University , Chongqing 401331 , China
| | - Hua Guo
- Department of Chemistry and Chemical Biology , University of New Mexico , Albuquerque , New Mexico 87131 , USA
| | - Robert E Continetti
- Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive , La Jolla , California 92093-0340 , USA .
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15
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Shen BB, Benitez Y, Lunny KG, Continetti RE. Internal energy dependence of the photodissociation dynamics of O3− using cryogenic photoelectron-photofragment coincidence spectroscopy. J Chem Phys 2017; 147:094307. [PMID: 28886639 DOI: 10.1063/1.4986500] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ben B. Shen
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093, USA
| | - Yanice Benitez
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093, USA
| | - Katharine G. Lunny
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093, USA
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry, University of California, 9500 Gilman Drive, La Jolla, San Diego, California 92093, USA
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16
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Saha K, Prabhakaran A, Chandrasekaran V, Rappaport ML, Heber O, Zajfman D. An experimental setup to study delayed electron emission upon photoexcitation of trapped polyatomic anions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:053101. [PMID: 28571459 DOI: 10.1063/1.4982034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A Velocity Map Imaging (VMI) spectrometer has been designed and integrated with an electrostatic ion beam trap to study delayed electron emission from trapped polyatomic anions upon photodetachment. The VMI spectrometer is small in size and can record a wide range of photoelectron energies, with variable magnification. Delayed electron emission can be recorded in our experimental setup for any time duration after the photoexcitation of the polyatomic anions. Experiments were carried out with trapped O- and C5- ions to demonstrate the capability of the spectrometer. Delayed electron emissions from C5- as well as prompt photoelectrons from O- were detected by the VMI spectrometer upon photoexcitation. The design and performance of the spectrometer are presented in detail.
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Affiliation(s)
- K Saha
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
| | - A Prabhakaran
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
| | - V Chandrasekaran
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
| | - M L Rappaport
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
| | - O Heber
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
| | - D Zajfman
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 234 Herzl Street, Rehovot 7610001, Israel
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17
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Abstract
Recent experimental and theoretical advances in transient reaction dynamics probed by photodetachment of polyatomic anions are reviewed.
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Affiliation(s)
- Robert E. Continetti
- Department of Chemistry and Biochemistry
- University of California San Diego
- La Jolla
- USA
| | - Hua Guo
- Department of Chemistry and Chemical Biology
- University of New Mexico
- Albuquerque
- USA
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18
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Ray AW, Agarwal J, Shen BB, Schaefer HF, Continetti RE. Energetics and transition-state dynamics of the F + HOCH3 → HF + OCH3 reaction. Phys Chem Chem Phys 2016; 18:30612-30621. [DOI: 10.1039/c6cp06409d] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Probing the transition state of the F + HOCH3 → HF + OCH3 reaction using photoelectron–photofragment coincidence spectroscopy accesses reactants, products, stable van der Waals complexes and long-lived metastable complexes.
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Affiliation(s)
- Amelia W. Ray
- Department of Chemistry and Biochemistry
- University of California, San Diego
- La Jolla
- USA
| | - Jay Agarwal
- Center for Computational Quantum Chemistry
- Department of Chemistry
- University of Georgia
- Athens
- USA
| | - Ben B. Shen
- Department of Chemistry and Biochemistry
- University of California, San Diego
- La Jolla
- USA
| | - H. F. Schaefer
- Center for Computational Quantum Chemistry
- Department of Chemistry
- University of Georgia
- Athens
- USA
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry
- University of California, San Diego
- La Jolla
- USA
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19
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Wang LS. Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions. J Chem Phys 2015; 143:040901. [DOI: 10.1063/1.4927086] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Lai-Sheng Wang
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA
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20
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Pedersen HB, Svendsen A, Harbo LS, Kiefer HV, Kjeldsen H, Lammich L, Toker Y, Andersen LH. Characterization of a new electrostatic storage ring for photofragmentation experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:063107. [PMID: 26133828 DOI: 10.1063/1.4922826] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We describe the design of and the first commissioning experiments with a newly constructed electrostatic storage ring named SAPHIRA (Storage Ring in Aarhus for PHoton-Ion Reaction Analysis). With an intense beam of Cu(-) at 4 keV, the storage ring is characterized in terms of the stored ion beam decay rate, the longitudinal spreading of an injected ion bunch, as well as the direct measurements of the transverse spatial distributions under different conditions of storage. The ion storage stability in SAPHIRA was investigated systematically in a selected region of its electrical configuration space.
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Affiliation(s)
- H B Pedersen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - A Svendsen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - L S Harbo
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - H V Kiefer
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - H Kjeldsen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - L Lammich
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
| | - Y Toker
- Departement of Physics, Bar Ilan University, Ramat Gan 5290002, Israel
| | - L H Andersen
- Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C, Denmark
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21
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Lu YJ, Lehman JH, Lineberger WC. A versatile, pulsed anion source utilizing plasma-entrainment: characterization and applications. J Chem Phys 2015; 142:044201. [PMID: 25637979 DOI: 10.1063/1.4906300] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A novel pulsed anion source has been developed, using plasma entrainment into a supersonic expansion. A pulsed discharge source perpendicular to the main gas expansion greatly reduces unwanted "heating" of the main expansion, a major setback in many pulsed anion sources in use today. The design principles and construction information are described and several examples demonstrate the range of applicability of this anion source. Large OH(-)(Ar)n clusters can be generated, with over 40 Ar solvating OH(-). The solvation energy of OH(-)(Ar)n, where n = 1-3, 7, 12, and 18, is derived from photoelectron spectroscopy and shows that by n = 12-18, each Ar is bound by about 10 meV. In addition, cis- and trans- HOCO(-) are generated through rational anion synthesis (OH(-) + CO + M → HOCO(-) + M) and the photoelectron spectra compared with previous results. These results, along with several further proof-of-principle experiments on solvation and transient anion synthesis, demonstrate the ability of this source to efficiently produce cold anions. With modifications to two standard General Valve assemblies and very little maintenance, this anion source provides a versatile and straightforward addition to a wide array of experiments.
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Affiliation(s)
- Yu-Ju Lu
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Julia H Lehman
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - W Carl Lineberger
- JILA and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
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22
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Shen BB, Poad BLJ, Continetti RE. Photoelectron-photofragment coincidence studies of the tert-butoxide anion (CH3)3CO((-)), the carbanion isomer (CH3)2CH2COH((-)), and corresponding radicals. J Phys Chem A 2014; 118:10223-32. [PMID: 25289788 DOI: 10.1021/jp5090235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A study of the photodetachment and dissociative photodetachment (DPD) of the C(4)H(9)O(-) isomers tert-butoxide, (CH(3))(3)CO(-), and the α-hydroxy carbanion (CH(3))(2)C(CH(2))OH(-) is reported. Photoelectron-photofragment coincidence spectroscopy was used to study these anions at 387, 537, and 600 nm. Supported by CBS-QB3 ab initio calculations, the product mass and translational energy distributions were found to be consistent with dissociation of either highly excited (CH3)(3)CO radicals or (CH(3))(2)C(CH2)OH alkylhydroxy radicals. Vibrationally resolved photoelectron spectra of stable radicals at 537 and 600 nm in conjunction with Franck-Condon simulations were used to assign the dominant channel to tert-butoxide ((CH(3)3)CO(-)) anions thermalized to a vibrational temperature of 550 K. DPD is assigned to highly vibrationally excited radicals produced by photodetachment of unrelaxed tert-butoxide products formed at an effective source temperature of 1400 K. The higher energy carbanion was found to be a minor channel and was not observed to dissociate. Calculated energetics for photodetachment and DPD of (CH(3))(3)CO(-) and (CH(3))(2)C(CH(2))OH(-) are discussed and compared with the experimental results.
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Affiliation(s)
- Ben B Shen
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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23
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Otto R, Ma J, Ray AW, Daluz JS, Li J, Guo H, Continetti RE. Imaging Dynamics on the F + H
2
O → HF + OH Potential Energy Surfaces from Wells to Barriers. Science 2014; 343:396-9. [DOI: 10.1126/science.1247424] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Rico Otto
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jianyi Ma
- Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, China
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Amelia W. Ray
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jennifer S. Daluz
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jun Li
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Hua Guo
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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24
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Ray AW, Shen BB, Poad BL, Continetti RE. State-resolved predissociation dynamics of the formyloxyl radical. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2013.11.061] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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Johnson CJ, Otto R, Continetti RE. Spectroscopy and dynamics of the HOCO radical: insights into the OH + CO → H + CO2 reaction. Phys Chem Chem Phys 2014; 16:19091-105. [DOI: 10.1039/c4cp02593h] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photoelectron–photofragment coincidence experiments coupled with quantum chemistry and dynamics calculations have significantly enhanced our understanding of the reactive intermediate HOCO.
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Affiliation(s)
| | - Rico Otto
- Department of Chemistry and Biochemistry
- University of California
- San Diego
- La Jolla, USA
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry
- University of California
- San Diego
- La Jolla, USA
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26
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Poad BLJ, Ray AW, Continetti RE. Dissociative photodetachment of the ethoxide anion and stability of the ethoxy radical CH3CH2O•. J Phys Chem A 2013; 117:12035-41. [PMID: 23924067 DOI: 10.1021/jp404343w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ethoxy radical is an important species in combustion chemistry; however, considerable debate regarding the fragmentation pathways exists. In order to examine the stability and dissociation dynamics of the ethoxy radical in the two lowest electronic states, dissociative photodetachment experiments at 3.20 eV were carried out on the ethoxide anion, CH3CH2O(-), and its per-deuterated isotopologue. Production of excited radicals by photodetachment of the alkoxide anion was found to lead to only CH3 + H2CO products, with no indication of the energetically allowed H-loss channel, H + CH3CHO. Ab initio calculations for the anionic and neutral surfaces, including relevant isomerization and dissociation barriers, were carried out using the CBS-QB3 method to aid in interpretation of the data. The energetics observed in the photoelectron-photofragment coincidence spectra indicate that the calculated barrier (0.70 eV) for the process CH3CH2O → CH3 + H2CO and the stability of the CH3CH2O radical relative to those products are upper limits.
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Affiliation(s)
- Berwyck L J Poad
- Department of Chemistry and Biochemistry, University of California, San Diego , 9500 Gilman Drive, La Jolla, California 92093-0340, United States
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27
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Rahinov I, Toker Y, Heber O, Strasser D, Rappaport M, Schwalm D, Zajfman D. Lifetime measurements in an electrostatic ion beam trap using image charge monitoring. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:033302. [PMID: 22462914 DOI: 10.1063/1.3694997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A technique for mass-selective lifetime measurements of keV ions in a linear electrostatic ion beam trap is presented. The technique is based on bunching the ions using a weak RF potential and non-destructive ion detection by a pick-up electrode. This method has no mass-limitation, possesses the advantage of inherent mass-selectivity, and offers a possibility of measuring simultaneously the lifetimes of different ion species with no need for prior mass-selection.
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Affiliation(s)
- Igor Rahinov
- Department of Particle Physics and Astrophysics, Weizmann Institute of Science, 76100 Rehovot, Israel.
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