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Electron Emission Cross Section from Methane under 250 keV Proton Impact. ATOMS 2023. [DOI: 10.3390/atoms11030049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023] Open
Abstract
We measure double differential cross sections (DDCS) of electrons emitted from CH4 molecules in collisions with 250 keV protons. The projectile ions are obtained from a 400 kV electron cyclotron resonance-based ion accelerator (ECRIA). We study the energy and angular distributions of the electron DDCS. The observed double and single differential and the total cross section are compared with the state-of-the-art continuum distorted wave eikonal initial state (CDW-EIS) model predictions. Two different approaches are used considering the different target descriptions: complete neglect of differential overlap (CNDO) and molecular orbital (MO) approximations. The MO model uses two different scaling parameters (d = 0.7 and 1.0). In the energy distribution of the DDCS, the carbon KLL Auger line is also observed at 240 eV. The single differential cross section (SDCS) and total cross section (TCS) are derived. Both the MO-based CDW-EIS models are in good agreement with the experimental results; however, the CNDO approach overestimates the data.
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Zhang Y, Wang B, Wei L, Jiang T, Yu W, Hutton R, Zou Y, Chen L, Wei B. Proton migration in hydrocarbons induced by slow highly charged ion impact. J Chem Phys 2019; 150:204303. [PMID: 31153159 DOI: 10.1063/1.5088690] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Different from most of the previous studies using light or photons, we use highly charged ions as projectiles to activate proton migration in the smallest saturated and unsaturated hydrocarbon molecules, i.e., CH4 and C2H2. The H3 + formation channel (H3 + + CH+) and isomerization channel (C+ + CH2 +), serving as indicators of proton migration, are observed in the fragmentation of CH4 and C2H2 dications. Corresponding kinematical information, i.e., kinetic energy release, is for the first time obtained in the collisions with highly charged ions. In particular, for the C+ + CH2 + channel, a new pathway is identified, which is tentatively attributed to the isomerization on high-lying states of acetylene dication. The kinetic energy release spectra for other two-body breakup channels are also determined and precursor dication states could thus be identified.
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Affiliation(s)
- Y Zhang
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - B Wang
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - L Wei
- School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China
| | - T Jiang
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - W Yu
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - R Hutton
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - Y Zou
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - L Chen
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
| | - B Wei
- Department of Nuclear Science and Technology, Institute of Modern Physics, Fudan University, Shanghai 200433, China
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Ekanayake N, Severt T, Nairat M, Weingartz NP, Farris BM, Kaderiya B, Feizollah P, Jochim B, Ziaee F, Borne K, Raju P K, Carnes KD, Rolles D, Rudenko A, Levine BG, Jackson JE, Ben-Itzhak I, Dantus M. H 2 roaming chemistry and the formation of H 3+ from organic molecules in strong laser fields. Nat Commun 2018; 9:5186. [PMID: 30518927 PMCID: PMC6281587 DOI: 10.1038/s41467-018-07577-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 11/06/2018] [Indexed: 11/11/2022] Open
Abstract
Roaming mechanisms, involving the brief generation of a neutral atom or molecule that stays in the vicinity before reacting with the remaining atoms of the precursor, are providing valuable insights into previously unexplained chemical reactions. Here, the mechanistic details and femtosecond time-resolved dynamics of H3+ formation from a series of alcohols with varying primary carbon chain lengths are obtained through a combination of strong-field laser excitation studies and ab initio molecular dynamics calculations. For small alcohols, four distinct pathways involving hydrogen migration and H2 roaming prior to H3+ formation are uncovered. Despite the increased number of hydrogens and possible combinations leading to H3+ formation, the yield decreases as the carbon chain length increases. The fundamental mechanistic findings presented here explore the formation of H3+, the most important ion in interstellar chemistry, through H2 roaming occurring in ionic species. H2 roaming is associated with H3+ formation when certain organic molecules are exposed to strong laser fields. Here, the mechanistic details and time-resolved dynamics of H3+ formation from a series of alcohols were obtained and found that the product yield decreases as the carbon chain length increases.
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Affiliation(s)
- Nagitha Ekanayake
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Travis Severt
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Muath Nairat
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Nicholas P Weingartz
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Benjamin M Farris
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Balram Kaderiya
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Peyman Feizollah
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Bethany Jochim
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Farzaneh Ziaee
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Kurtis Borne
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Kanaka Raju P
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Kevin D Carnes
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Daniel Rolles
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Artem Rudenko
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Benjamin G Levine
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - James E Jackson
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA
| | - Itzik Ben-Itzhak
- J. R. Macdonald Laboratory, Physics Department, Kansas State University, Manhattan, KS, 66506, USA
| | - Marcos Dantus
- Department of Chemistry, Michigan State University, East Lansing, MI, 48824, USA. .,Department of Physics and Astronomy, Michigan State University, East Lansing, MI, 48824, USA.
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Bug MU, Gargioni E, Baek WY, Hilgers G, Nettelbeck H, Rosenfeld AB, Rabus H. Proton-impact ionisation cross sections for nanodosimetric track structure simulations. RADIATION PROTECTION DOSIMETRY 2014; 161:474-477. [PMID: 24324254 DOI: 10.1093/rpd/nct317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Monte Carlo simulations of the particle track structure require accurate ion- and electron-impact cross-section data of the medium. These data are scarce and often inconsistent when measured by different groups. In this work, literature data on ionisation cross sections (CSs) of nitrogen and propane for protons with energies 0.1-10 MeV are reviewed and implemented in the code PTra. Methane data were used to obtain proton-impact CSs of propane due to their absence in the literature. PTra is benchmarked by comparing simulated particle-track parameters to experimental results, measured with an ion-counting nanodosemeter.
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Affiliation(s)
- M U Bug
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2522, Australia
| | - E Gargioni
- University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
| | - W Y Baek
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - G Hilgers
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - H Nettelbeck
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
| | - A B Rosenfeld
- Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2522, Australia
| | - H Rabus
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
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5
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Wei B, Zhang Y, Wang X, Lu D, Lu GC, Zhang BH, Tang YJ, Hutton R, Zou Y. Fragmentation mechanisms for methane induced by 55 eV, 75 eV, and 100 eV electron impact. J Chem Phys 2014; 140:124303. [PMID: 24697437 DOI: 10.1063/1.4868651] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The fragmentation of CH4 (2+) dications following 55 eV, 75 eV, and 100 eV electron impact double ionization of methane was studied using a cold target recoil-ion momentum spectroscopy. From the measured momentum of each recoil ion, the momentum of the neutral particles has been deduced and the kinetic energy release distribution for the different fragmentation channels has been obtained. The doubly charged molecular ions break up into three or more fragments in one or two-step processes, resulting in different signatures in the data. We observed the fragmentation of CH4 (2+) dications through different mechanisms according to the momentum of the neutral particles. For example, our result shows that there are three reaction channels to form CH2 (+), H(+), and H, one synchronous concerted reaction channel and two two-step reaction channels. For even more complicated fragmentation processes of CH4 (2+) dications, the fragmentation mechanism can still be identified in the present measurements. The slopes of the peak in the ion-ion coincidence spectra were also estimated here, as they are also related to the fragmentation mechanism.
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Affiliation(s)
- B Wei
- Applied Ion Beam Physics Laboratory, Fudan University, Key Laboratory of the Ministry of Education, Shanghai 200433, China
| | - Y Zhang
- Applied Ion Beam Physics Laboratory, Fudan University, Key Laboratory of the Ministry of Education, Shanghai 200433, China
| | - X Wang
- Applied Ion Beam Physics Laboratory, Fudan University, Key Laboratory of the Ministry of Education, Shanghai 200433, China
| | - D Lu
- Applied Ion Beam Physics Laboratory, Fudan University, Key Laboratory of the Ministry of Education, Shanghai 200433, China
| | - G C Lu
- Applied Ion Beam Physics Laboratory, Fudan University, Key Laboratory of the Ministry of Education, Shanghai 200433, China
| | - B H Zhang
- Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-986, Mianyang 621900, China
| | - Y J Tang
- Research Center of Laser Fusion, China Academy of Engineering Physics, P.O. Box 919-986, Mianyang 621900, China
| | - R Hutton
- Applied Ion Beam Physics Laboratory, Fudan University, Key Laboratory of the Ministry of Education, Shanghai 200433, China
| | - Y Zou
- Applied Ion Beam Physics Laboratory, Fudan University, Key Laboratory of the Ministry of Education, Shanghai 200433, China
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Bug MU, Gargioni E, Nettelbeck H, Baek WY, Hilgers G, Rosenfeld AB, Rabus H. Ionization cross section data of nitrogen, methane, and propane for light ions and electrons and their suitability for use in track structure simulations. Phys Rev E 2013; 88:043308. [PMID: 24229305 DOI: 10.1103/physreve.88.043308] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Indexed: 11/07/2022]
Abstract
Track structure Monte Carlo simulations are frequently applied in micro- and nanodosimetry to calculate the radiation transport in detail. The use of a well-validated set of cross section data in such simulation codes ensures accurate calculations of transport parameters, such as ionization yields. These cross section data are, however, scarce and often discrepant when measured by different groups. This work surveys literature data on ionization and charge-transfer cross sections of nitrogen, methane, and propane for electrons, protons, and helium particles, focusing on the energy range between 100 keV and 20 MeV. Based on the evaluated data, different models for the parametrization of the cross section data are implemented in the code ptra, developed for simulating proton and alpha particle transport in an ion-counting nanodosimeter. The suitability of the cross section data is investigated by comparing the calculated mean ionization cluster size and energy loss with experimental results in either nitrogen or propane. For protons, generally good agreement between measured and simulated data is found when the Rudd model is used in ptra. For alpha particles, however, a considerable influence of different parametrizations of cross sections for ionization and charge transfer is observed. The ptra code using the charge-transfer data is, nevertheless, successfully benchmarked by the experimental data for the calculation of nanodosimetric quantities, but remaining discrepancies still have to be further investigated (up to 13% lower energy loss and 19% lower mean ionization cluster size than in the experiment). A continuation of this work should investigate data for the energy loss per interaction as well as differential cross section data of nitrogen and propane. Interpolation models for ionization and charge-transfer data are proposed. The Barkas model, frequently used for a determination of the effective charge in the ionization cross section, significantly underestimates both the energy loss (by up to 19%) and the mean ionization cluster size (up to 65%) for alpha particles. It is, therefore, not recommended for particle-track simulations.
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Affiliation(s)
- Marion U Bug
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany and Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, New South Wales 2522, Australia
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Charge Exchange and Fragmentation in Slow Collisions of He2+ with Water Molecules. ADVANCES IN QUANTUM CHEMISTRY 2007. [DOI: 10.1016/s0065-3276(06)52007-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Liu X, Shemansky DE. Analysis of electron impact ionization properties of methane. ACTA ACUST UNITED AC 2006. [DOI: 10.1029/2005ja011454] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Luna H, Montenegro EC. Fragmentation of water by heavy ions. PHYSICAL REVIEW LETTERS 2005; 94:043201. [PMID: 15783555 DOI: 10.1103/physrevlett.94.043201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2004] [Indexed: 05/24/2023]
Abstract
Absolute cross sections for fragmentation of water molecules by C3+ and O5+ ions over an energy region where the Bragg peak maximizes were measured for ionization, electron capture, and electron loss channels. A collision regime where sigmaSigmaOq+> or =sigmaH2O+ was reached for the first time, producing large abundances of H+ and O+ fragments in comparison to proton impact. Our findings have straightforward implications in the subsequent fast chemistry at the ionization site and on the O production in the first stages of water radiolysis. An unexpected channel-independent relationship between the cross sections for the fragmentation products, which is also approximately independent of the particle type, energy, and charge state, is found. A model is presented to explain such behavior allowing the cross sections of all fragmentation products to be obtained from single and double electron removal cross sections.
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Affiliation(s)
- H Luna
- Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, Caixa Postal 38071, Rio de Janeiro 22452-970, Brazil
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