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Seeing the solvated electron in action: First-principles molecular dynamics of NO3− and N2O reduction. Radiat Phys Chem Oxf Engl 1993 2022. [DOI: 10.1016/j.radphyschem.2021.109810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Mirsaleh-Kohan N, Esmaili S, Bass AD, Huels MA, Sanche L. Chemical transformation of molecular ices containing N 2O and C 2D 2 by low energy electrons: New chemical species of astronomical interest. J Chem Phys 2021; 154:224706. [PMID: 34241211 DOI: 10.1063/5.0040884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We have employed electron stimulated desorption (ESD) and x-ray photoelectron spectroscopy (XPS) to study the chemical species generated from multilayer films of N2O, C2D2, and mixtures thereof (i.e., N2O/C2D2) by the impact of low energy electrons with energies between 30 and 70 eV. Our ESD results for pure films of N2O show the production of numerous fragment cations and anions, and of larger molecular ions, of sufficient kinetic energy to escape into vacuum, which are likely formed by ion-molecule scattering in the film. Ion-molecule scattering is also responsible for the production of cations from C2D2 films that contain as many as six or seven carbon atoms. Many of the same anions and cations desorb from N2O/C2D2 mixtures, as well as new species, which is the result of ion-molecule scattering in the film. Anion desorption signals further indicate the formation of C-N containing species within the irradiated films. XPS spectra of N1s, C1s, and O1s lines reveal the fragmentation of N-O bonds and gradual formation of molecules containing species containing O-C=O, C=O, and C-O functional groups. A comparison between ESD and XPS findings suggests that species observed in the ESD channel are primarily products of reactions taking place at the film-vacuum interface, while those observed in the XPS derive from reactions occurring within the solid.
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Affiliation(s)
- Nasrin Mirsaleh-Kohan
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Sasan Esmaili
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Andrew D Bass
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Michael A Huels
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
| | - Leon Sanche
- Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1H 5N4, Canada
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Sawyer JC, Miller TM, Ard SG, Sweeny BC, Viggiano AA, Shuman NS. Thermal rate constants for electron attachment to N 2O: An example of endothermic attachment. J Chem Phys 2020; 153:074306. [PMID: 32828078 DOI: 10.1063/5.0016121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Rate constants for dissociative electron attachment to N2O yielding O- have been measured as a function of temperature from 400 K to 1000 K. Detailed modeling of kinetics was needed to derive the rate constants at temperatures of 700 K and higher. In the 400 K-600 K range, upper limits are given. The data from 700 K to 1000 K follow the Arrhenius equation behavior described by 2.4 × 10-8 e-0.288 eV/kT cm3 s-1. The activation energy derived from the Arrhenius plot is equal to the endothermicity of the reaction. However, calculations at the CCSD(T)/complete basis set level suggest that the lowest energy crossing between the neutral and anion surfaces lies 0.6 eV above the N2O equilibrium geometry and 0.3 eV above the endothermicity of the dissociative attachment. Kinetic modeling under this assumption is in modest agreement with the experimental data. The data are best explained by attachment occurring below the lowest energy crossing of the neutral and valence anion surfaces via vibrational Feshbach resonances.
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Affiliation(s)
- Jordan C Sawyer
- NRC Postdoc at Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
| | - Thomas M Miller
- Boston College Institute for Scientific Research, Boston, Massachusetts 02549, USA
| | - Shaun G Ard
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
| | - Brendan C Sweeny
- NRC Postdoc at Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
| | - Albert A Viggiano
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
| | - Nicholas S Shuman
- Air Force Research Laboratory, Space Vehicles Directorate, Kirtland Air Force Base, New Mexico 87117, USA
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Liu Y, Solari E, Scopelliti R, Fadaei Tirani F, Severin K. Lewis Acid-Mediated One-Electron Reduction of Nitrous Oxide. Chemistry 2018; 24:18809-18815. [PMID: 30426605 DOI: 10.1002/chem.201804709] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Indexed: 11/10/2022]
Abstract
The one-electron reduction of nitrous oxide (N2 O) was achieved using strong Lewis acids E(C6 F5 )3 (E=B or Al) in combination with metallocenes. In the case of B(C6 F5 )3 , electron transfer to N2 O required a powerful reducing agent such as Cp*2 Co (Cp*=pentamethylcyclopentadienyl). In the presence of Al(C6 F5 )3 , on the other hand, the reactions could be performed with weaker reducing agents such as Cp*2 Fe or Cp2 Fe (Cp=cyclopentadienyl). The Lewis acid-mediated electron transfer from the metallocene to N2 O resulted in cleavage of the N-O bond, generating N2 and the oxyl radical anion [OE(C6 F5 )3 ]⋅- . The latter is highly reactive and engages in C-H activation reactions. It was possible to trap the radical by addition of the Gomberg dimer, which acts as a source of the trityl radical.
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Affiliation(s)
- Yizhu Liu
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Euro Solari
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Rosario Scopelliti
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Farzaneh Fadaei Tirani
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Kay Severin
- Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
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Riebe D, Erler A, Ritschel T, Beitz T, Löhmannsröben HG, Beil A, Blaschke M, Ludwig T. Atmospheric pressure chemical ionization of explosives induced by soft X-radiation in ion mobility spectrometry: mass spectrometric investigation of the ionization reactions of drift gasses, dopants and alkyl nitrates. JOURNAL OF MASS SPECTROMETRY : JMS 2016; 51:566-577. [PMID: 28239970 DOI: 10.1002/jms.3784] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/04/2016] [Accepted: 04/29/2016] [Indexed: 06/06/2023]
Abstract
A promising replacement for the radioactive sources commonly encountered in ion mobility spectrometers is a miniaturized, energy-efficient photoionization source that produce the reactant ions via soft X-radiation (2.8 keV). In order to successfully apply the photoionization source, it is imperative to know the spectrum of reactant ions and the subsequent ionization reactions leading to the detection of analytes. To that end, an ionization chamber based on the photoionization source that reproduces the ionization processes in the ion mobility spectrometer and facilitates efficient transfer of the product ions into a mass spectrometer was developed. Photoionization of pure gasses and gas mixtures containing air, N2 , CO2 and N2 O and the dopant CH2 Cl2 is discussed. The main product ions of photoionization are identified and compared with the spectrum of reactant ions formed by radioactive and corona discharge sources on the basis of literature data. The results suggest that photoionization by soft X-radiation in the negative mode is more selective than the other sources. In air, adduct ions of O2- with H2 O and CO2 were exclusively detected. Traces of CO2 impact the formation of adduct ions of O2- and Cl- (upon addition of dopant) and are capable of suppressing them almost completely at high CO2 concentrations. Additionally, the ionization products of four alkyl nitrates (ethylene glycol dinitrate, nitroglycerin, erythritol tetranitrate and pentaerythritol tetranitrate) formed by atmospheric pressure chemical ionization induced by X-ray photoionization in different gasses (air, N2 and N2 O) and dopants (CH2 Cl2 , C2 H5 Br and CH3 I) are investigated. The experimental studies are complemented by density functional theory calculations of the most important adduct ions of the alkyl nitrates (M) used for their spectrometric identification. In addition to the adduct ions [M + NO3 ]- and [M + Cl]- , adduct ions such as [M + N2 O2 ]- , [M + Br]- and [M + I]- were detected, and their gas-phase structures and energetics are investigated by density functional theory calculations. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Daniel Riebe
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, Germany
| | - Alexander Erler
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, Germany
| | - Thomas Ritschel
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, Germany
| | - Toralf Beitz
- Physical Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, Potsdam, Germany
| | | | - Andreas Beil
- Bruker Daltonik, Permoserstrasse 15, Leipzig, Germany
| | | | - Thomas Ludwig
- Bruker Daltonik, Permoserstrasse 15, Leipzig, Germany
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