1
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Zhang R, Yan S, Song H, Guo H, Ning C. Probing the activated complex of the F + NH 3 reaction via a dipole-bound state. Nat Commun 2024; 15:3858. [PMID: 38719855 PMCID: PMC11079065 DOI: 10.1038/s41467-024-48202-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2024] [Accepted: 04/23/2024] [Indexed: 05/12/2024] Open
Abstract
Experimental characterization of the transition state poses a significant challenge due to its fleeting nature. Negative ion photodetachment offers a unique tool for probing transition states and their vicinity. However, this approach is usually limited to Franck-Condon regions. For example, high-lying Feshbach resonances with an excited HF stretching mode (vHF = 2-4) were recently identified in the transition-state region of the F + NH3 → HF + NH2 reaction through photo-detaching FNH3- anions, but the direct photodetachment failed to observe the lower-lying vHF = 0,1 resonances and bound states due apparently to negligible Franck-Condon factors. Indeed, these weak transitions can be resonantly enhanced via a dipole-bound state (DBS) formed between an electron and the polar FNH3 species. In this study, we unveil a series of Feshbach resonances and bound states along the F + NH3 reaction path via a DBS by combining high-resolution photoelectron spectroscopy with high-level quantum dynamical computations. This study presents an approach for probing the activated complex in a reaction by negative ion photodetachment through a DBS.
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Affiliation(s)
- Rui Zhang
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Frontier Science Center for Quantum Information, Tsinghua University, 100084, Beijing, China
| | - Shuaiting Yan
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Frontier Science Center for Quantum Information, Tsinghua University, 100084, Beijing, China
| | - Hongwei Song
- State Key Laboratory of Magnetic Resonance Spectroscopy and Imaging, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, China.
| | - Hua Guo
- Department of Chemistry and Chemical Biology, Center for Computational Chemistry, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Chuangang Ning
- Department of Physics, State Key Laboratory of Low Dimensional Quantum Physics, Frontier Science Center for Quantum Information, Tsinghua University, 100084, Beijing, China.
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2
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Observation of resonances in the transition state region of the F + NH 3 reaction using anion photoelectron spectroscopy. Nat Chem 2023; 15:194-199. [PMID: 36509851 DOI: 10.1038/s41557-022-01100-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 10/24/2022] [Indexed: 12/14/2022]
Abstract
The transition state of a chemical reaction is a dividing surface on the reaction potential energy surface (PES) between reactants and products and is thus of fundamental interest in understanding chemical reactivity. The transient nature of the transition state presents challenges to its experimental characterization. Transition-state spectroscopy experiments based on negative-ion photodetachment can provide a direct probe of this region of the PES, revealing the detailed vibrational structure associated with the transition state. Here we study the F + NH3 → HF + NH2 reaction using slow photoelectron velocity-map imaging spectroscopy of cryogenically cooled FNH3- anions. Reduced-dimensionality quantum dynamical simulations performed on a global PES show excellent agreement with the experimental results, enabling the assignment of spectral structure. Our combined experimental-theoretical study reveals a manifold of vibrational Feshbach resonances in the product well of the F + NH3 PES. At higher energies, the spectra identify features attributed to resonances localized across the transition state and into the reactant complex that may impact the bimolecular reaction dynamics.
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3
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Delgado-Granados LH, Arango CA, López JG. Preparation of vibrational quasi-bound states of the transition state complex BrHBr from the bihalide ion BrHBr . Phys Chem Chem Phys 2022; 24:21250-21260. [PMID: 36040431 DOI: 10.1039/d2cp03120e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Efficient strategies that allow the preparation of molecular systems in particular vibrational states are important in the application of quantum control schemes to chemical reactions. In this paper, we propose the preparation of quasi-bound vibrational states of the collinear transition state complex BrHBr, from vibrational states of the bihalide ion BrHBr-, that favor the bond selective breakage of BrHBr. The results shown complement the investigation that we reported in a previous paper, [A. J. Garzón-Ramírez, J. G. López and C. A. Arango, Int. J. Quantum Chem., 2018, 24, e25784], in which we demonstrated the feasibility of controlling the bond selective decomposition of the collinear BrHBr using linear combinations of reactive resonances. We employed a dipole moment surface, calculated at the QCISD/d-aug-cc-pVTZ level of theory, to simulate the interaction of the BrHBr- ground vibrational state with heuristically optimized sequences of ultrashort infrared linear chirped laser pulses to achieve a target vibrational state, resulting from expanding a chosen linear combination of reactive resonances of BrHBr in terms of vibrational eigenstates of BrHBr-. The results of our simulations show final states that capture the most relevant features of the target state with different levels of description depending on the sequence of laser pulses employed. We also discuss ways of improving the description of the target state and possible limitations of our approach.
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Affiliation(s)
| | - Carlos A Arango
- Departamento de Ciencias Químicas, Universidad Icesi, Cali, Colombia
| | - José G López
- Departamento de Química, Universidad del Valle, A.A. 25360, Cali, Colombia.
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4
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Conder CJ, Jawale H, Wenthold PG. Mass spectrometry studies of nitrene anions. MASS SPECTROMETRY REVIEWS 2021:e21751. [PMID: 34842299 DOI: 10.1002/mas.21751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/03/2021] [Indexed: 06/13/2023]
Abstract
Nitrene anions are a class of reactive intermediates that provide a means for studying the corresponding neutral molecules via electron photodetachment spectroscopy and photoelectron spectroscopy. The added electron makes it possible for protected nitrene anions to be manipulated by external electric and magnetic fields of a mass spectrometer. Nitrene anions also display their own unique reactivities as reagents, which have been investigated using ion/molecule reactions. Mass spectrometry of negative ions has thereby provided information on the electronic states, reactivities, and thermochemical properties of nitrene intermediates. This review also includes a discussion of condensed-phase nitrene anions.
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Affiliation(s)
- Cory J Conder
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Harshal Jawale
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
| | - Paul G Wenthold
- Department of Chemistry, Purdue University, West Lafayette, Indiana, USA
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5
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Saito K, Sugiura Y, Miyazaki T, Takahashi Y, Takayanagi T. Quantum calculations of the photoelectron spectra of the OH -·NH 3 anion: implications for OH + NH 3→ H 2O + NH 2 reaction dynamics. Phys Chem Chem Phys 2021; 23:6950-6958. [PMID: 33729225 DOI: 10.1039/d0cp06514e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
We present the results of quantum dynamics calculations for analyzing the experimentally measured photoelectron spectra of the OH-·NH3 anion complex. Detachment of an excess electron of OH-·NH3 initially produces a molecular arrangement, which is close to the transition-state structure of the neutral OH + NH3→ H2O + NH2 hydrogen abstraction reaction due to the Franck-Condon principle, and thus finally leads to the OH + NH3 or H2O + NH2 asymptotic channel. We used both the path integral method and the reduced-dimensionality quantum wave packet method to simulate the photoelectron spectra of the OH-·NH3 anion. The calculated spectra were found to be in qualitative agreement with the experimental spectra. It was found that the photodetached complex mainly dissociates into the OH + NH3 channel; however, we found that the hydrogen exchange process also contributes to the photodetachment spectra.
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Affiliation(s)
- Kohei Saito
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Sakura-ku, Saitama City, Saitama 338-8570, Japan.
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6
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Miyazaki T, Watabe Y, Hashimoto Y, Takahashi Y, Sugiura Y, Saito K, Takayanagi T. Theoretical Analysis of the Formylmethylene Anion Photoelectron Spectrum: Importance of Wolff Rearrangement Dynamics. J Phys Chem A 2020; 124:9721-9728. [DOI: 10.1021/acs.jpca.0c09067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Takaaki Miyazaki
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan
| | - Yuya Watabe
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan
| | - Yu Hashimoto
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan
| | - Yukinobu Takahashi
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan
| | - Yutaro Sugiura
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan
| | - Kohei Saito
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan
| | - Toshiyuki Takayanagi
- Department of Chemistry, Saitama University, Shimo-Okubo 255, Saitama City, Saitama 338-8570, Japan
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7
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Sugiura Y, Takayanagi T. Franck–Condon simulations of transition-state spectra for the OH + H2O and OD + D2O reactions. Phys Chem Chem Phys 2020; 22:20685-20692. [DOI: 10.1039/d0cp03681a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantum wave packet calculations in reduced dimensions were performed to analyze the experimentally measured transition-state spectra of the OH + H2O and OD + D2O hydrogen exchange reactions.
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Affiliation(s)
- Yutaro Sugiura
- Department of Chemistry
- Saitama University
- Saitama City
- Japan
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8
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Takayanagi T. Quantum dynamics analysis of transition-state spectrum for the SH + H 2S → H 2S + SH reaction. Phys Chem Chem Phys 2020; 22:19845-19854. [DOI: 10.1039/d0cp03072d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Quantum dynamics calculations were performed to understand transition-state spectroscopy of the SH + H2S hydrogen atom transfer reaction.
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9
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Panja SK, Verma S, Saha S. Probing phenol dimer in molecular complex: Role of nitro group and stabilizing agent. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2019.05.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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10
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Pino GA, Jara-Toro RA, Aranguren-Abrate JP, Dedonder-Lardeux C, Jouvet C. Dissociative photodetachment vs. photodissociation of aromatic carboxylates: the benzoate and naphthoate anions. Phys Chem Chem Phys 2019; 21:1797-1804. [DOI: 10.1039/c8cp07162d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photodetachment leads to a stable radical and to dissociation. Both processes are characterized by the kinetic energy release of the neutral particles.
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Affiliation(s)
- Gustavo A. Pino
- INFIQC: Instituto de Investigaciones en Fisicoquímica de Córdoba (CONICET-UNC)
- Haya de la Torre y Medina Allende
- Ciudad Universitaria
- X5000HUA Córdoba
- Argentina
| | - Rafael A. Jara-Toro
- INFIQC: Instituto de Investigaciones en Fisicoquímica de Córdoba (CONICET-UNC)
- Haya de la Torre y Medina Allende
- Ciudad Universitaria
- X5000HUA Córdoba
- Argentina
| | - Juan P. Aranguren-Abrate
- Physique des Interactions Ioniques et Moléculaires (PIIM)
- UMR-CNRS 7345
- Aix-Marseille Université
- Avenue Escadrille Normandie-Niémen
- 13397 Marseille Cedex 20
| | - Claude Dedonder-Lardeux
- Physique des Interactions Ioniques et Moléculaires (PIIM)
- UMR-CNRS 7345
- Aix-Marseille Université
- Avenue Escadrille Normandie-Niémen
- 13397 Marseille Cedex 20
| | - Christophe Jouvet
- Physique des Interactions Ioniques et Moléculaires (PIIM)
- UMR-CNRS 7345
- Aix-Marseille Université
- Avenue Escadrille Normandie-Niémen
- 13397 Marseille Cedex 20
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11
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Kasai T, Che DC, Tsai PY, Nakamura M, Muthiah B, Lin KC. Roaming and chaotic behaviors in collisional and photo-initiated molecular-beam reactions: a role of classical vs. quantum nonadiabatic dynamics. RENDICONTI LINCEI. SCIENZE FISICHE E NATURALI 2018. [DOI: 10.1007/s12210-018-0709-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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12
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Abstract
Slow photoelectron velocity-map imaging spectroscopy of cryogenically cooled anions (cryo-SEVI) is a powerful technique for elucidating the vibrational and electronic structure of neutral radicals, clusters, and reaction transition states. SEVI is a high-resolution variant of anion photoelectron spectroscopy based on photoelectron imaging that yields spectra with energy resolution as high as 1-2 cm-1. The preparation of cryogenically cold anions largely eliminates hot bands and dramatically narrows the rotational envelopes of spectral features, enabling the acquisition of well-resolved photoelectron spectra for complex and spectroscopically challenging species. We review the basis and history of the SEVI method, including recent experimental developments that have improved its resolution and versatility. We then survey recent SEVI studies to demonstrate the utility of this technique in the spectroscopy of aromatic radicals, metal and metal oxide clusters, nonadiabatic interactions between excited states of small molecules, and transition states of benchmark bimolecular reactions.
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Affiliation(s)
- Marissa L Weichman
- Department of Chemistry, University of California, Berkeley, California 94720, USA; , .,Current affiliation: JILA, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, USA; , .,Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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13
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Wang T, Yang T, Xiao C, Sun Z, Zhang D, Yang X, Weichman ML, Neumark DM. Dynamical resonances in chemical reactions. Chem Soc Rev 2018; 47:6744-6763. [DOI: 10.1039/c8cs00041g] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The transition state is a key concept in the field of chemistry and is important in the study of chemical kinetics and reaction dynamics.
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Affiliation(s)
- Tao Wang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Tiangang Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Chunlei Xiao
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Zhigang Sun
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Donghui Zhang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | - Xueming Yang
- State Key Laboratory of Molecular Reaction Dynamics
- Dalian Institute of Chemical Physics
- Chinese Academy of Sciences
- Dalian
- China
| | | | - Daniel M. Neumark
- Department of Chemistry
- University of California at Berkeley
- Berkeley
- USA
- Chemical Sciences Division
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14
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Hou GL, Wang XB, McCoy AB, Borden WT. Experimental and Theoretical Studies of the F• + H–F Transition-State Region by Photodetachment of [F–H–F]−. J Phys Chem A 2017; 121:7895-7902. [DOI: 10.1021/acs.jpca.7b07682] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gao-Lei Hou
- Physical
Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | - Xue-Bin Wang
- Physical
Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, MS K8-88, Richland, Washington 99352, United States
| | - Anne B. McCoy
- Department
of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Weston Thatcher Borden
- Department
of Chemistry and the Center for Advanced Scientific Computing and
Modeling, University of North Texas, 1155 Union Circle, #305070, Denton, Texas 76203-5017, United States
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15
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Takayanagi T. Nonadiabatic quantum dynamics calculations of transition state spectroscopy of I + HI and I + DI reactions: the existence of long life vibrational bonding resonances. Phys Chem Chem Phys 2017; 19:29125-29133. [DOI: 10.1039/c7cp05478e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nonadiabatic quantum dynamics calculations were performed to understand the transition state spectroscopy of I + HI and I + DI reactions.
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Affiliation(s)
- Toshiyuki Takayanagi
- Department of Chemistry, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City
- Saitama 338-8570
- Japan
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16
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Negative Ion Photoelectron Spectroscopy and Its Use in Investigating the Transition States for Some Organic Reactions. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2017. [DOI: 10.1016/bs.apoc.2017.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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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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Boesl U. Time-of-flight mass spectrometry: Introduction to the basics. MASS SPECTROMETRY REVIEWS 2017; 36:86-109. [PMID: 27859457 DOI: 10.1002/mas.21520] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 08/02/2016] [Accepted: 08/19/2016] [Indexed: 05/04/2023]
Abstract
The intention of this tutorial is to introduce into the basic concepts of time-of-flight mass spectrometry, beginning with the most simple single-stage ion source with linear field-free drift region and continuing with two-stage ion sources combined with field-free drift regions and ion reflectors-the so-called reflectrons. Basic formulas are presented and discussed with the focus on understanding the physical relations of geometric and electric parameters, initial distribution of ionic parameters, ion flight times, and ion flight time incertitude. This tutorial is aimed to help the applicant to identify sources of flight time broadening which limit good mass resolution and sources of ion losses which limit sensitivity; it is aimed to stimulate creativity for new experimental approaches by discussing a choice of instrumental options and to encourage those who toy with the idea to build an own time-of-flight mass spectrometer. Large parts of mathematics are shifted into a separate chapter in order not to overburden the text with too many mathematical deviations. Rather, thumb-rule formulas are supplied for first estimations of geometry and potentials when designing a home-built instrument, planning experiments, or searching for sources of flight time broadening. © 2016 Wiley Periodicals, Inc. Mass Spec Rev 36:86-109, 2017.
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Affiliation(s)
- Ulrich Boesl
- Department of Chemistry, Physical Chemistry, Technische Universität München, Garching, Germany
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19
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Sáez-Rábanos V, Verdasco JE, Aoiz FJ, Herrero VJ. Influence of vibration in the reactive scattering of D + MuH: the effect of dynamical bonding. Phys Chem Chem Phys 2016; 18:13530-7. [PMID: 27138743 PMCID: PMC4931899 DOI: 10.1039/c6cp01305h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The dynamics of the D + MuH(v = 1) reaction has been investigated using time-independent quantum mechanical calculations. The total reaction cross sections and rate coefficients have been calculated for the two exit channels of the reaction leading, respectively, to DMu + H and DH + Mu. Over the 100-1000 K temperature range investigated the rate coefficients for the DMu + H channel are of the order of 10(-10) cm(3) s(-1) and those for the DH + Mu channel vary between 1 × 10(-12) and 8 × 10(-11) cm(3) s(-1). These results point to a virtually barrierless reaction for the DMu + H channel and to the presence of a comparatively small barrier for the DH + Mu channel and are consistent with the profiles of their respective collinear vibrationally adiabatic potentials (VAPs). The effective barrier in the VAP of the DH + Mu channel is located in the reactant valley and, consequently, translation is found to be more efficient than vibration for the promotion of the reaction over a large energy interval in the post threshold region. Below this barrier, the DH + Mu channel can be accessible through an indirect mechanism implying crossing from the DMu + H pathway. The most salient feature found in the present study is revealed in the total reaction cross section for the DMu + H channel, which shows a sharp resonance caused by the presence of a deep well in the vibrationally adiabatic potential. This well has a dynamical origin, reminiscent of that found recently in the vibrationally bonded BrMuBr complex [Fleming, et al., Angew. Chem., Int. Ed., 2014, 53, 1], and is due to the stabilizing effect of the light Mu atom oscillating between the heavier H and D isotopes and to the bond softening associated with vibrational excitation of MuH.
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Affiliation(s)
- V Sáez-Rábanos
- Departamento de Sistemas y Recursos Naturales. E.T.S. de Ingeniería de Montes, Forestal y del Medio Natural, Universidad Politécnica de Madrid, 28040 Madrid, Spain.
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20
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Theoretical analysis of the transition-state spectrum of the cyclooctatetraene unimolecular reaction: Three degree-of-freedom model calculations. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.06.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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21
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Yoshida T, Sato K, Takayanagi T. First-principles simulations of transition state spectra of the I + HI and I + DI reactions and vibrational bonding in IMuI. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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22
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Manz J, Sato K, Takayanagi T, Yoshida T. From photoelectron detachment spectra of BrHBr−, BrDBr− and IHI−, IDI− to vibrational bonding of BrMuBr and IMuI. J Chem Phys 2015; 142:164308. [DOI: 10.1063/1.4918980] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Abstract
A long-sought but elusive new type of chemical bond, occurring on a minimum-free, purely repulsive potential energy surface, has recently been convincingly shown to be possible on the basis of high-level quantum-chemical calculations. This type of bond, termed a vibrational bond, forms because the total energy, including the dynamical energy of the nuclei, is lower than the total energy of the dissociated products, including their vibrational zero-point energy. For this to be the case, the ZPE of the product molecule must be very high, which is ensured by replacing a conventional hydrogen atom with its light isotope muonium (Mu, mass = 1/9 u) in the system Br-H-Br, a natural transition state in the reaction between Br and HBr. A paramagnetic species observed in the reaction Mu +Br2 has been proposed as a first experimental sighting of this species, but definitive identification remains challenging.
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24
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Buytendyk AM, Graham JD, Collins KD, Bowen KH, Wu CH, Wu JI. The hydrogen bond strength of the phenol–phenolate anionic complex: a computational and photoelectron spectroscopic study. Phys Chem Chem Phys 2015; 17:25109-13. [DOI: 10.1039/c5cp04754d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The phenol–phenolate anionic complex was studied in vacuo by negative ion photoelectron spectroscopy using 193 nm photons and by density functional theory (DFT) computations at the ωB97XD/6-311+G(2d,p) level.
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Affiliation(s)
| | | | - Kim D. Collins
- IMET and Department of Microbiology and Immunology
- University of Maryland School of Medicine
- Baltimore
- USA
| | - Kit H. Bowen
- Department of Chemistry
- Johns Hopkins University
- Baltimore
- USA
| | - Chia-Hua Wu
- Department of Chemistry
- University of Houston
- Houston
- USA
| | - Judy I. Wu
- Department of Chemistry
- University of Houston
- Houston
- USA
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25
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Fleming DG, Manz J, Sato K, Takayanagi T. Über eine fundamentale Änderung der Art der chemischen Bindung durch Isotopensubstitution. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201408211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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26
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Fleming DG, Manz J, Sato K, Takayanagi T. Fundamental Change in the Nature of Chemical Bonding by Isotopic Substitution. Angew Chem Int Ed Engl 2014; 53:13706-9. [DOI: 10.1002/anie.201408211] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Indexed: 11/10/2022]
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27
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28
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Graham JD, Buytendyk AM, Wang D, Bowen KH, Collins KD. Strong, low-barrier hydrogen bonds may be available to enzymes. Biochemistry 2014; 53:344-9. [PMID: 24359447 DOI: 10.1021/bi4014566] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The debate over the possible role of strong, low-barrier hydrogen bonds in stabilizing reaction intermediates at enzyme active sites has taken place in the absence of an awareness of the upper limits to the strengths of low-barrier hydrogen bonds involving amino acid side chains. Hydrogen bonds exhibit their maximal strengths in isolation, i.e., in the gas phase. In this work, we measured the ionic hydrogen bond strengths of three enzymatically relevant model systems in the gas phase using anion photoelectron spectroscopy; we calibrated these against the hydrogen bond strength of HF2(-), measured using the same technique, and we compared our results with other gas-phase experimental data. The model systems studied here, the formate-formic acid, acetate-acetic acid, and imidazolide-imidazole anionic complexes, all exhibit very strong hydrogen bonds, whose strengths compare favorably with that of the hydrogen bifluoride anion, the strongest known hydrogen bond. The hydrogen bond strengths of these gas-phase complexes are stronger than those typically estimated as being required to stabilize enzymatic intermediates. If there were to be enzyme active site environments that can facilitate the retention of a significant fraction of the strengths of these isolated (gas-phase), hydrogen bonded couples, then low-barrier hydrogen bonding interactions might well play important roles in enzymatic catalysis.
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Affiliation(s)
- Jacob D Graham
- Department of Chemistry, Johns Hopkins University , Baltimore, Maryland 21218, United States
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29
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Scattering resonance state of Br+HBr(v=0)→BrH(v′=0)+Br reaction explored by partial potential energy surface method. Chem Res Chin Univ 2013. [DOI: 10.1007/s40242-013-3254-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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30
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Affiliation(s)
- Ryan M. Young
- Department of Chemistry, University of California, Berkeley, California 94720,
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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31
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Kasai T, Che DC, Tsai PY, Lin KC. Reaction Dynamics with Molecular Beams and Oriented Molecular Beams: A Tool for Looking Closer to Chemical Reactions and Photodissociations. J CHIN CHEM SOC-TAIP 2012. [DOI: 10.1002/jccs.201100735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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32
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Fleming DG, Cottrell SP, McKenzie I, Macrae RM. New results for the formation of a muoniated radical in the Mu + Br2 system: a van der Waals complex or evidence for vibrational bonding in Br–Mu–Br? Phys Chem Chem Phys 2012; 14:10953-66. [DOI: 10.1039/c2cp41366c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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33
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WANG HUAYANG, SUN XIAOMIN, FENG DACHENG, CAI ZHENGTING. THE PARTIAL POTENTIAL ENERGY SURFACE AND SCATTERING RESONANCE STATE OF THE STATE-TO-STATE REACTION Br + HBr(v) → BrH(v′) + Br. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633606002271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this paper, the partial potential energy surface (PPESs) of the Br + HBr and Br - + HBr systems including the minimum energy path and the vibrational potential curves were constructed at MP2/6-311++G** level, based on the conception and constructing approach of the PPESs previously proposed. These results obtained from the PPESs were compared with those from the high resolved threshold photodetachment spectrum of the BrHBr - anion measured by Neumark et al., J Phys Chem94, 1377–1388, 1990. On the basis of the PPESs, the scattering resonance states of the Br + HBr (v) → BrH (v′) + Br state-to-state reaction were studied and the satisfactory results were obtained. Subsequently, we calculated the width and lifetime of the resonance states in this reaction by the one-dimensional square potential well model, and obtained some results consistent to the experiments.
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Affiliation(s)
- HUAYANG WANG
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China
| | - XIAOMIN SUN
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China
| | - DACHENG FENG
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China
| | - ZHENGTING CAI
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China
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34
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SUN XIAOMIN, WANG HUAYANG, CAI ZHENGTING, FENG DACHENG, BIAN WENSHENG. PARTIAL POTENTIAL ENERGY SURFACE AND ITS APPLICATIONS IN REACTIVE RESONANCES. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2011. [DOI: 10.1142/s0219633604001197] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The conception of partial potential energy surface (PPES) is presented in this paper. PPES can be abstracted from complete potential energy surface (CPES), therefore, it can be constructed with ab initio quantum chemical method. For the systems of H + H 2→ H 2+ H , I + HI → IH + I and I -+ HI → IH + I -, the construction and applications of PPES are proposed as typical examples. It can be seen that the applications of PPES demonstrate remarkable virtues in the analysis of reaction mechanism and the formation of scattering resonance states.
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Affiliation(s)
- XIAOMIN SUN
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, China
| | - HUAYANG WANG
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, China
| | - ZHENGTING CAI
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, China
| | - DACHENG FENG
- Institute of Theoretical Chemistry, Shandong University, Jinan 250100, China
| | - WENSHENG BIAN
- State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry Chinese Academy of Science, Beijing, 100080, China
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35
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Kopyra J, König-Lehmann C, Illenberger E. Low energy (0–10 eV) electron driven reactions in the halogenated organic acids CCl3COOH, CClF2COOH, and CF3CHNH2COOH (trifluoroalanine). J Chem Phys 2011; 135:124307. [DOI: 10.1063/1.3641479] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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36
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Cheng M, Feng Y, Du Y, Zhu Q, Zheng W, Czakó G, Bowman JM. Communication: Probing the entrance channels of the X + CH4 → HX + CH3 (X = F, Cl, Br, I) reactions via photodetachment of X−–CH4. J Chem Phys 2011; 134:191102. [DOI: 10.1063/1.3591179] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Min Cheng
- National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuan Feng
- National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yikui Du
- National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Qihe Zhu
- National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Weijun Zheng
- National Laboratory of Molecular Sciences, State Key Laboratory of Molecular Reaction Dynamics, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Gábor Czakó
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
| | - Joel M. Bowman
- Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA
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37
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Entfellner M, Opalka D, Boesl U. Photodetachment-photoelectron spectroscopy of HS- x H2S and DS- x D2S: the transition states of the SH + H2S and SD + D2S reactions. Phys Chem Chem Phys 2010; 12:9034-42. [PMID: 20556264 DOI: 10.1039/b925941d] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The transition state region for neutral hydrogen transfer reactions can be accessed by photodetachment of a stable negative ion with a geometry similar to that of the neutral transition state. In this work the SH + H(2)S and SD + D(2)S reactions are investigated by photodetachment-photoelectron spectroscopy of HS(-) x H(2)S and DS(-) x D(2)S. The spectra exhibit vibrational structure which is attributed to the antisymmetric stretching mode (H-atom motion) of the neutral transitions state for H-atom transfer. The spectra are compared to one-dimensional simulations performed using a wave packet propagation scheme. Electronic structure calculations of the anionic, neutral and transition-state geometries and calculations of the vertical detachment energy at different levels of theory are used to support the analysis of the spectra. A vertical detachment energy VDE of 3.06 eV has been determined.
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38
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39
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Yen TA, Garand E, Shreve AT, Neumark DM. Anion Photoelectron Spectroscopy of C3N− and C5N−. J Phys Chem A 2009; 114:3215-20. [DOI: 10.1021/jp9093996] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Terry A. Yen
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Etienne Garand
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Alexander T. Shreve
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
| | - Daniel M. Neumark
- Department of Chemistry, University of California, Berkeley, California 94720, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720
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40
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Wijeratne NR, Fonte MD, Ronemus A, Wyss PJ, Tahmassebi D, Wenthold PG. Photoelectron Spectroscopy of Chloro-Substituted Phenylnitrene Anions. J Phys Chem A 2009; 113:9467-73. [PMID: 19655776 DOI: 10.1021/jp9039594] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Neloni R. Wijeratne
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, and Department of Chemistry, Indiana University−Purdue University Fort Wayne, Fort Wayne, Indiana 46805
| | - Maria Da Fonte
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, and Department of Chemistry, Indiana University−Purdue University Fort Wayne, Fort Wayne, Indiana 46805
| | - Alan Ronemus
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, and Department of Chemistry, Indiana University−Purdue University Fort Wayne, Fort Wayne, Indiana 46805
| | - Phillip J. Wyss
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, and Department of Chemistry, Indiana University−Purdue University Fort Wayne, Fort Wayne, Indiana 46805
| | - Daryoush Tahmassebi
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, and Department of Chemistry, Indiana University−Purdue University Fort Wayne, Fort Wayne, Indiana 46805
| | - Paul G. Wenthold
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, and Department of Chemistry, Indiana University−Purdue University Fort Wayne, Fort Wayne, Indiana 46805
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41
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Neumark DM. Slow electron velocity-map imaging of negative ions: applications to spectroscopy and dynamics. J Phys Chem A 2009; 112:13287-301. [PMID: 19032143 DOI: 10.1021/jp807182q] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Anion photoelectron spectroscopy (PES) has become one of the most versatile techniques in chemical physics. This article briefly reviews the history of anion PES and some of its applications. It describes efforts to improve the resolution of this technique, including anion zero electron kinetic energy (ZEKE) and the recently developed method of slow electron velocity-map imaging (SEVI). Applications of SEVI to studies of vibronic coupling in open-shell systems and the spectroscopy of prereactive van der Waals complexes are then discussed.
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Affiliation(s)
- Daniel M Neumark
- Department of Chemistry, University of California, Berkeley, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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42
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Toboła R, Chałasiński G, Kłos J, Szczęśniak MM. Ab initio study of the Br([sup 2]P)–HBr van der Waals complex. J Chem Phys 2009; 130:184304. [DOI: 10.1063/1.3123168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [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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Sheehan SM, Parsons BF, Yen TA, Furlanetto MR, Neumark DM. Anion photoelectron spectroscopy of C5H−. J Chem Phys 2008; 128:174301. [DOI: 10.1063/1.2912056] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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44
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Sheehan SM, Parsons BF, Zhou J, Garand E, Yen TA, Moore DT, Neumark DM. Characterization of cyclic and linear C3H− and C3H via anion photoelectron spectroscopy. J Chem Phys 2008; 128:034301. [DOI: 10.1063/1.2812561] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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45
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Wang H, Lu X, Sun X, Cai Z, Feng D. New calculation method on the lifetime of the reactive scattering resonance states. Chem Phys Lett 2007. [DOI: 10.1016/j.cplett.2007.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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46
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Takayanagi T. Theoretical study of the H+Br2 and Mu+Br2 reactions: A new ab initio potential energy surface and quantum dynamics calculations. Chem Phys 2007. [DOI: 10.1016/j.chemphys.2007.02.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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47
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Metz RB, Bradforth SE, Neumark DM. Transition State Spectroscopy of Bimolecular Reactions Using Negative Ion Photodetachment. ADVANCES IN CHEMICAL PHYSICS 2007. [DOI: 10.1002/9780470141380.ch1] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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48
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Parsons BF, Sheehan SM, Kautzman KE, Yen TA, Neumark DM. Photoelectron imaging of I2− at 5.826eV. J Chem Phys 2006; 125:244301. [PMID: 17199345 DOI: 10.1063/1.2363990] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We report the anion photoelectron spectrum of I2- taken at 5.826 eV detachment energy using velocity mapped imaging. The photoelectron spectrum exhibits bands resulting from transitions to the bound regions of the X 1Sigmag+(0g+), A' 3Piu(2u), A 3Piu(1u), and B 3Piu(0u+) electronic states as well as bands resulting from transitions to the repulsive regions of several I2 electronic states: the B' 3Piu(0u-), B" 1Piu(1u), 3Pig(2g), a 3Pig(1g), 3Pig(0g-), and C 3Sigmau+(1u) states. We simulate the photoelectron spectrum using literature parameters for the I2- and I2 ground and excited states. The photoelectron spectrum includes bands resulting from transitions to several high-lying excited states of I2 that have not been seen experimentally: 3Pig(0g-), 1Pig3(1g), 1 3Sigmag-3(0g+), and the 1Sigmag-3(0u-) states of I2. Finally, the photoelectron spectrum at 5.826 eV allows for the correction of a previous misassignment for the vertical detachment energy of the I2 B 3Piu(0u+) state.
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Affiliation(s)
- Bradley F Parsons
- Department of Chemistry, University of California at Berkeley, Berkeley, California 94720-1460 and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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49
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Abstract
Experiments are reviewed in which key problems in chemical dynamics are probed by experiments based on photodetachment and/or photoexcitation of negative ions. Examples include transition state spectroscopy of biomolecular reactions, spectroscopy of open shell van der Waals complexes, photodissociation of free radicals, and time-resolved dynamics in clusters. The experimental methods used in these investigations are described along with representative systems that have been studied.
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Affiliation(s)
- Daniel M Neumark
- Department of Chemistry,University of California, Berkeley, California 94720, USA.
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50
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Meloni G, Sheehan SM, Parsons BF, Neumark DM. Spectroscopic investigation of Al2N and its anion via negative ion photoelectron spectroscopy. J Phys Chem A 2006; 110:3527-32. [PMID: 16526632 DOI: 10.1021/jp0562781] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Negative ion photoelectron spectroscopy was used to elucidate the electronic and geometric structure of the gaseous Al2N/Al2N- molecules, using photodetachment wavelengths of 416 nm (2.977 eV), 355 nm (3.493 eV), and 266 nm (4.661 eV). Three electronic bands are observed and assigned to the X2Sigma(u)+ <-- X1Sigma(g)+, A2Pi(u) <-- X1Sigma(g)+, and B2Sigma(g)+ <-- X1Sigma(g)+ electronic transitions, with the caveat that one or both excited states may be slightly bent. With the aid of density functional theory calculations and Franck-Condon spectral simulations, we determine the adiabatic electron affinity of Al2N, 2.571 +/- 0.008 eV, along with geometry changes upon photodetachment, vibrational frequencies, and excited-state term energies. Observation of excitation of the odd vibrational levels of the antisymmetric stretch (nu3) suggests a breakdown of the Franck-Condon approximation, caused by the vibronic coupling between the X2Sigma(u)+ and B2Sigma(g)+ electronic states through the nu3 mode.
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Affiliation(s)
- Giovanni Meloni
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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