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Kashinski D, Talbi D, Hickman A. Using block diagonalization to determine dissociating autoionizing states: Application to N 2H, and the outlook for SH. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158403003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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2
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El Ghazaly MOA, Mitchell JBA, Jureta JJ, Defrance P. Electron impact induced fragmentation of N₂H⁺ and N₂D⁺. J Phys Chem A 2014; 118:10020-7. [PMID: 25333899 DOI: 10.1021/jp5084967] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Electron impact dissociation of protonated and deuterated nitrogen ions has been studied using a crossed beams apparatus. Absolute cross sections for dissociation channels producing N(+) and NH(+), respectively, are presented. The observations of subthreshold signals in these measurements indicate the presence of ro-vibrationally and possibly electronically excited states in the parent ions. Comparisons with other measurements are given.
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Affiliation(s)
- M O A El Ghazaly
- King Abdulaziz City for Sciences and Technology (KACST) , Riyadh 1442, Saudi Arabia
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3
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Kashinski D, Talbi D, Hickman A. Ab initio calculations of autoionizing states using block diagonalization: Collinear diabatic states for dissociative recombination of electrons with. Chem Phys Lett 2012. [DOI: 10.1016/j.cplett.2012.01.037] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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4
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Thompson MGK, White MR, Linford BD, King KA, Robinson MM, Parnis JM. Fourier transform infrared matrix-isolation analysis of acetaldehyde fragmentation products after charge exchange with Ar•+ under varied ionization density conditions. JOURNAL OF MASS SPECTROMETRY : JMS 2011; 46:1071-1078. [PMID: 22012674 DOI: 10.1002/jms.1990] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The products of the Ar(•+) charge exchange ionization of acetaldehyde have been isolated and compared with related photoionization results and computational work. Acetaldehyde has been used to assess the effect of varied ion density in the ionization region of the electron bombardment matrix isolation apparatus. The amount of acetaldehyde destruction has been measured for constant gas-sample composition and constant ionization current for two anode geometries: a pin anode and a plate anode. For the same ionization current, a pin-shaped anode demonstrates higher precursor molecule destruction efficiency (85%) than the plate-shaped anode (30%), resulting in substantial effect on the yield and quantity of isolated products. When the plate anode is used, the observed infrared products correspond to matrix-isolated carbon monoxide (CO), methane (CH(4)), ketene (CH(2)CO), ethynyloxy radical (HCCO), formyl radical (HCO(•)), acetyl radical (CH(3)CO(•)), vinyl alcohol (H(2)C = CH-OH), and cationic proton-bound dimer, Ar(2)H(+). When the pin anode is used, the same products are observed with different relative proportions and new absorption features corresponding to dicarbon monoxide (CCO) and methyl radical (CH(3)(•)) are observed. The surprising observation of infrared absorptions corresponding to vinyl alcohol along with low yield of products anticipated through the analysis of photoelectron-photoionization coincidence measurements suggests that the initially formed fragmentation products are able to further react within the matrix-isolation environment to influence observed product yields. Related experiments, using the isotopomer CD(3)CHO, suggest that the observed products are formed via radical-radical reactions that occur under the high pressure conditions of the matrix isolation environment.
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Mann JE, Xie Z, Savee JD, Bowman JM, Continetti RE. Dissociation Dynamics of Isotopologs of CH5 Studied by Charge Exchange of CH5+ with Cs and Quasiclassical Trajectory Calculations. J Phys Chem A 2010; 114:11408-16. [DOI: 10.1021/jp105119v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jennifer E. Mann
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Zhen Xie
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - John D. Savee
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
| | - Joel M. Bowman
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, United States, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, 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, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, United States
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Gerardi HK, Breen KJ, Guasco TL, Weddle GH, Gardenier GH, Laaser JE, Johnson MA. Survey of Ar-tagged predissociation and vibrationally mediated photodetachment spectroscopies of the vinylidene anion, C2H2-. J Phys Chem A 2010; 114:1592-601. [PMID: 20088616 DOI: 10.1021/jp9095419] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report predissociation spectra of Ar-tagged C(2)H(2)(-) and C(2)D(2)(-) anions, and explore vibrationally mediated photodetachment from various vibrational levels of the bare C(2)H(2)(-) ion using velocity-map imaging. Intense photodetachment resonances are observed in the C-H stretching region that are strongly correlated with vibrational hot bands in the anion photoelectron spectra, indicating that one-color, resonant two-photon photodetachment (R2PD) is complicated by excitation of vibrationally excited states with autodetaching upper levels embedded in the continuum. Isolation of the R2PD spectrum was achieved using a two-color, IR-IR scheme in which vibrational excitation and photodetachment were carried out in two separate laser interaction regions.
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Affiliation(s)
- Helen K Gerardi
- Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520, USA
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7
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Savee JD, Mann JE, Continetti RE. Dissociative Charge Exchange Dynamics of HOCO+ and DOCO+. J Phys Chem A 2009; 114:1485-91. [DOI: 10.1021/jp907480y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- John D. Savee
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340
| | - Jennifer E. Mann
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340
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8
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Savee JD, Thomas RD, Mann JE, Continetti RE. Dissociative charge exchange dynamics of HN2+ and DN2+. J Chem Phys 2009; 131:134301. [DOI: 10.1063/1.3236803] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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9
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Stepanov NF, Novakovskaya YV. Rate constants of atomic hydrogen formation in H3O+(H2O) n + e → H + (H2O) n gas-phase processes. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2009. [DOI: 10.1134/s0036024409090155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Zhaunerchyk V, Geppert WD, Rosén S, Vigren E, Hamberg M, Kamińska M, Kashperka I, af Ugglas M, Semaniak J, Larsson M, Thomas RD. Investigation into the vibrational yield of OH products in the OH+H+H channel arising from the dissociative recombination of H3O+. J Chem Phys 2009; 130:214302. [DOI: 10.1063/1.3141434] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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11
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Tachikawa H, Orr-Ewing AJ. Ab Initio Molecular Dynamics Study on the Electron Capture Processes of Protonated Methane (CH5+). J Phys Chem A 2008; 112:11575-81. [DOI: 10.1021/jp806114y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Hiroto Tachikawa
- Division of Materials Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan, and School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
| | - Andrew J. Orr-Ewing
- Division of Materials Chemistry, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan, and School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K
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12
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Thomas RD. When electrons meet molecular ions and what happens next: dissociative recombination from interstellar molecular clouds to internal combustion engines. MASS SPECTROMETRY REVIEWS 2008; 27:485-530. [PMID: 18618616 DOI: 10.1002/mas.20169] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The interaction of matter with its environment is the driving force behind the evolution of 99% of the observed matter in the universe. The majority of the visible universe exists in a state of weak ionization, the so called fourth state of matter: plasma. Plasmas are ubiquitous, from those occurring naturally; interstellar molecular clouds, cometary comae, circumstellar shells, to those which are anthropic in origin; flames, combustion engines and fusion reactors. The evolution of these plasmas is driven by the interaction of the plasma constituents, the ions, and the electrons. One of the most important subsets of these reactions is electron-molecular ion recombination. This process is significant for two very important reasons. It is an ionization reducing reaction, removing two ionised species and producing neutral products. Furthermore, these products may themselves be reactive radical species which can then further drive the evolution of the plasma. The rate at which the electron reacts with the ion depends on many parameters, for examples the collision energy, the internal energy of the ion, and the structure of the ion itself. Measuring these properties together with the manner in which the system breaks up is therefore critical if the evolution of the environment is to be understood at all. Several techniques have been developed to study just such reactions to obtain the necessary information on the parameters. In this paper the focus will be on one the most recently developed of these, the Ion Storage Ring, together with the detection tools and techniques used to extract the necessary information from the reaction.
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Affiliation(s)
- Richard D Thomas
- Department of Physics, Albanova University Centre, Stockholm University, S106 91 Stockholm, Sweden.
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13
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Geppert W, Larsson M. Dissociative recombination in the interstellar medium and planetary ionospheres. Mol Phys 2008. [DOI: 10.1080/00268970802322074] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Mann JE, Xie Z, Savee JD, Braams BJ, Bowman JM, Continetti RE. Probing the Structure of CH5+ by Dissociative Charge Exchange. J Am Chem Soc 2008; 130:3730-1. [DOI: 10.1021/ja0782504] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jennifer E. Mann
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322
| | - Zhen Xie
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322
| | - John D. Savee
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322
| | - Bastiaan J. Braams
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322
| | - Joel M. Bowman
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322
| | - Robert E. Continetti
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, and Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322
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16
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Molek CD, Plasil R, McLain JL, Adams NG, Babcock LM. Experimental determination of energy disposal in the dissociative electron recombinations of CS2(+) and HCS2(+). J Phys Chem A 2008; 112:934-41. [PMID: 18186620 DOI: 10.1021/jp0777420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Vibronic optical emissions from CS(A1pi --> X1sigma+) and CS(a3pi --> X1sigma+) transitions have been identified from dissociative recombination (DR) of CS2(+) and HCS2(+) plasmas. All of the spectra were taken in flowing afterglow plasmas using an optical monochromator in the UV-visible wavelength region of 180-800 nm. For the CS(A --> X) and CS(a --> X) emissions, the relative vibrational distributions have been calculated for v' < 5 and v' < 3 in both types of plasmas for the CS(A) and CS(a) states, respectively. Both recombining plasmas show a population inversion from the v' = 0 to v' = 1 level of the CS(A) state, similar to other observations of the CS(A) state populations, which were generated using two other energetic processes. The possibility of spectroscopic cascading is addressed, such that transitions from upper level electronic states into the CS(A) and CS(a) states would affect the relative vibrational distribution, and there is no spectroscopic evidence supporting the cascading effect. Additionally, excited-state transitions from neutral sulfur (S(5S(2)0 --> 3P(2)) and S(5S(2)0 --> 3P(1))) and the products of ion-molecule reactions (CS(B1sigma+ --> A1pi), CS(+)(B2sigma+ --> A2pi(i)), and CS2(+) (A2pi(u) --> X2pi(g))) have been observed and are discussed.
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Affiliation(s)
- C D Molek
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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17
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McCarthy MC, Thaddeus P. Laboratory detection of the elusive HSCO+ isomer. J Chem Phys 2007; 127:221104. [DOI: 10.1063/1.2822042] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Molek CD, McLain JL, Poterya V, Adams NG. A remeasurement of the products for electron recombination of N2H+ using a new technique: no significant NH+N production. J Phys Chem A 2007; 111:6760-5. [PMID: 17542564 DOI: 10.1021/jp068965d] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A remeasurement of the product distribution from dissociative electron-ion recombination (DR) of N2H+ has been made using a new technique. The technique employs electron impact to ionize the neutral products prior to detection by a quadrupole mass analyzer. Two experimental approaches, both using pulsed gas techniques, isolate and quantify the DR products. In one approach, an electron-attaching gas is pulsed into a flowing afterglow to transiently quench DR. Results from this approach give an upper limit of 5% for the NH+N product channel. In the second approach, the reagent gas N2 is pulsed. The absolute percentages of products were monitored versus initial N2 concentration. Results from this approach also give an upper limit of 5% for NH+N production. This establishes that N2+H is the dominant channel, being at least between 95 and 100%, and that there is no significant NH production contrary to a recent storage ring measurement that yielded 64% NH+N and 36% N2+H. Possible reasons for this dramatic difference are discussed.
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Affiliation(s)
- C D Molek
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA
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19
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Snow JL, Orlova G, Blagojevic V, Bohme DK. Gas-Phase Ionic Syntheses of Amino Acids: β versus α. J Am Chem Soc 2007; 129:9910-7. [PMID: 17649994 DOI: 10.1021/ja068725b] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Both theoretical and experimental studies are reported for the gas-phase reactions of protonated hydroxylamine with acetic and propanoic acids which yield protonated glycine and alanine, GlyH+ and AlaH+, respectively. The key step for these reactions is an insertion of the amino group into a C-H bond. For the formation of AlaH+, the reaction barrier for insertion into a Cbeta-H bond is ca. 5 kcal.mol-1 lower than that for the insertion into a Calpha-H bond; the product beta-AlaH+ is ca. 6 kcal mol-1 lower in energy than alpha-AlaH+. Thus, both kinetics and thermodynamics favor formation of the beta-form. The energetic preference for the beta-form is due to more efficient hydrogen bonding between the amino group and the carbonyl oxygen in the limiting transition structure and in the beta-AlaH+ product. These theoretical results are in excellent accord with selected ion flow tube measurements of the gas-phase synthesis which show striking specificity for the beta-isomer according to multi-collision-induced dissociation of the AlaH+ product ion. The results suggest that Gly and beta-Ala found in carbonaceous chondrite meteorites are products of interstellar chemistry.
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Affiliation(s)
- Jamie L Snow
- Department of Chemistry, St. Francis Xavier University, Antigonish, Nova Scotia, Canada
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20
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Rosati RE, Skrzypkowski MP, Johnsen R, Golde MF. Yield of excited CO molecules from dissociative recombination of HCO+ and HOC+ ions with electrons. J Chem Phys 2007; 126:154302. [PMID: 17461621 DOI: 10.1063/1.2715943] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors have investigated CO band emissions arising from the dissociative recombination of HCO(+) and HOC(+) ions with thermal electrons in a flowing afterglow plasma. The quantitative analysis of the band intensities showed that HCO(+) recombination forms the long-lived CO(a (3)Pi) state with a yield of 0.23+/-0.12, while HOC(+) recombination favors formation of CO(a' (3)Sigma(+)) and CO(d (3)Delta) with a combined yield of greater than 0.4. The observed vibrational distribution for the CO(a) state reproduces theoretical predictions quite well. The vibrational distributions for CO(a') and CO(d) are, in part, inverted, presumably as a consequence of a change in CO equilibrium bond length during recombination. The observations are compatible with current knowledge of the potential surfaces of states of HCO and HCO(+).
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Affiliation(s)
- Richard E Rosati
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA
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21
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Petrik NG, Kimmel GA. Electron-stimulated production of molecular hydrogen at the interfaces of amorphous solid water films on Pt(111). J Chem Phys 2006; 121:3736-44. [PMID: 15303941 DOI: 10.1063/1.1773152] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The electron-stimulated production of molecular hydrogen (D(2), HD, and H(2)) from amorphous solid water (ASW) deposited on Pt(111) is investigated. Experiments with isotopically layered films of H(2)O and D(2)O are used to profile the spatial distribution of the electron-stimulated reactions leading to hydrogen within the water films. The molecular hydrogen yield has two components that have distinct reaction kinetics due to reactions that occur at the ASW/Pt interface and the ASW/vacuum interface, but not in the bulk. However, the molecular hydrogen yield as a function of the ASW film thickness in both pure and isotopically layered films indicates that the energy for the reactions is absorbed in the bulk of the films and electronic excitations migrate to the interfaces where they drive the reactions.
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Affiliation(s)
- Nikolay G Petrik
- Fundamental Sciences Directorate, Pacific Northwest National Laboratory, Mail Stop K8-88, Richland, Washington 99352, USA
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Adams NG, Poterya V, Babcock LM. Electron molecular ion recombination: product excitation and fragmentation. MASS SPECTROMETRY REVIEWS 2006; 25:798-828. [PMID: 16783766 DOI: 10.1002/mas.20084] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Electron-ion dissociative recombination is an important ionization loss process in any ionized gas containing molecular ions. This includes the interstellar medium, circumstellar shells, cometary comae, planetary ionospheres, fusion plasma boundaries, combustion flames, laser plasmas and chemical deposition and etching plasmas. In addition to controlling the ionization density, the process generates many radical species, which can contribute to a parallel neutral chemistry. Techniques used to obtain rate data and product information (flowing afterglows and storage rings) are discussed and recent data are reviewed including diatomic to polyatomic ions and cluster ions. The data are divided into rate coefficients and cross sections, including their temperature/energy dependencies, and quantitative identification of neutral reaction products. The latter involve both ground and electronically excited states and including vibrational excitation. The data from the different techniques are compared and trends in the data are examined. The reactions are considered in terms of the basic mechanisms (direct and indirect processes including tunneling) and recent theoretical developments are discussed. Finally, new techniques are mentioned (for product identification; electrostatic storage rings, including single and double rings; Coulomb explosion) and new ways forward are suggested.
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Affiliation(s)
- Nigel G Adams
- Department of Chemistry, University of Georgia, Athens, Georgia 30602, USA.
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Wheeler SE, Yamaguchi Y, Schaefer HF. Protonated carbonyl sulfide: Prospects for the spectroscopic observation of the elusive HSCO+ isomer. J Chem Phys 2006; 124:044322. [PMID: 16460177 DOI: 10.1063/1.2150819] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Spurred by the apparent conflict between ab initio predictions and infrared spectroscopic evidence regarding the relative stability of isomers of protonated carbonyl sulfide, key stationary points on the isomerization surface of HOCS(+) have been examined via systematic extrapolations of ab initio energies. Electron correlation has been accounted for using second-order Møller-Plesset perturbation theory and coupled cluster theory through triple excitations [CCSD, CCSD(T), and CCSDT] in conjunction with the correlation consistent hierarchy of basis sets, cc-pVXZ (X=D,T,Q,5,6). HSCO(+) is predicted to lie lower in energy than HOCS(+) by 4.86 kcal mol(-1), computed using the focal point extrapolation scheme of Allen and co-workers [J. Chem. Phys. 99, 4638 (1993)] with corrections for anharmonic zero-point vibrational energy, core correlation, non-Born-Oppenheimer, and scalar relativistic effects. A transition state has been located, constituting the barrier to isomerization of HSCO(+) to HOCS(+), lying 68.9 kcal mol(-1) higher in energy than HSCO(+). This is well above predicted exothermicity [DeltaH(r) (o)(0 K)=48.1 kcal mol(-1), cc-pVQZ CCSD(T)] for the reaction considered in the experiments (HSCO(+)+H(2)-->OCS+H(3) (+)). Though proton tunneling will lead to a lower effective barrier, this prediction is consistent with the lack of HSCO(+) in electrical discharges in H(2)OCS, since the relative populations of HOCS(+) and HSCO(+) will depend on the experimental details of the protonation route rather than the relative thermodynamic stability of the isomers. Anharmonic vibrational frequencies and vibrationally corrected rotational constants from cc-pVTZ CCSD(T) cubic and quartic force constants are provided, to aid in the spectroscopic observation of the energetically favorable but apparently elusive HSCO(+) isomer.
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Affiliation(s)
- Steven E Wheeler
- Center for Computational Chemistry, University of Georgia, Athens, Georgia 30602, USA
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24
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Geppert WD, Hamberg M, Thomas RD, Osterdahl F, Hellberg F, Zhaunerchyk V, Ehlerding A, Millar TJ, Roberts H, Semaniak J, af Ugglas M, Källberg A, Simonsson A, Kaminska M, Larsson M. Dissociative recombination of protonated methanol. Faraday Discuss 2006; 133:177-90; discussion 191-230, 449-52. [PMID: 17191449 DOI: 10.1039/b516010c] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The branching ratios of the different reaction pathways and the overall rate coefficients of the dissociative recombination reactions of CH3OH2+ and CD3OD2+ have been measured at the CRYRING storage ring located in Stockholm, Sweden. Analysis of the data yielded the result that formation of methanol or deuterated methanol accounted for only 3 and 6% of the total rate in CH3OH2+ and CD3OD2+, respectively. Dissociative recombination of both isotopomeres mainly involves fragmentation of the C-O bond, the major process being the three-body break-up forming CH3, OH and H (CD3, OD and D). The overall cross sections are best fitted by sigma = 1.2 +/- 0.1 x 10(-15) E(-1.15 +/- 0.02) cm2 and sigma = 9.6 +/- 0.9 x 10(-16) E(-1.20 +/- 0.02) cm2 for CH3OH2+ and CD3OD2+, respectively. From these values thermal reaction rate coefficients of k(T) = 8.9 +/- 0.9 x 10(-7) (T/300)(-0.59 +/- 0.02) cm3 s(-1) (CH3OH2+) and k(T) = 9.1 +/- 0.9 x 10(-7) (T/300)(-0.63 +/- 0.02) cm3 s(-1) (CD3OD2+) can be calculated. A non-negligible formation of interstellar methanol by the previously proposed mechanism via radiative association of CH3+ and H2O and subsequent dissociative recombination of the resulting CH3OH2+ ion to yield methanol and hydrogen atoms is therefore very unlikely.
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Affiliation(s)
- W D Geppert
- Molecular Physics Division, Department of Physics, Stockholm, Sweden.
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Biennier L, Alsayed-Ali M, Foutel-Richard A, Novotny O, Carles S, Rebrion-Rowe C, Rowe B. Laboratory measurements of the recombination of PAH ions with electrons: implications for the PAH charge state in interstellar clouds. Faraday Discuss 2006; 133:289-301; discussion 347-74, 449-52. [PMID: 17191453 DOI: 10.1039/b516858a] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Laboratory measurements of the recombination of polycyclic aromatic hydrocarbon (PAH) ions with electrons are presented. Experimental data have been obtained at room temperature for azulene (C10H8) and acenaphthene (C12H10) cations by the Flowing Afterglow with PhotoIons method. The results confirm that the recombination of PAH ions is fast although well below the geometrical limit. The set of our recent and present measurements reveal a definite trend of increasing rate with the number of carbon atoms of the PAH. This behaviour that needs further characterization is potentially of great interest for charge state models as recombination is a dominant mechanism of PAH ion destruction in the interstellar medium. The design of experiments to measure the recombination of larger PAHs and their temperature dependence is discussed.
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Affiliation(s)
- Ludovic Biennier
- Laboratoire de Physique des Atomes, Lasers, Molécules et Surfaces, UMR 6627 CNRS et Université de Rennes 1, France
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26
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Feuerbacher S, Santra R. Calculating molecular Rydberg states using the one-particle Green's function: application to HCO and C(NH2)3. J Chem Phys 2005; 123:194310. [PMID: 16321091 DOI: 10.1063/1.2122687] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A simple but accurate and computationally efficient method for routine ab initio calculations of molecular Rydberg states is described. The method, which can be applied to Rydberg states associated with a nondegenerate ion core, consists in the self-consistent solution of an effective one-electron problem. First, the restricted Hartree-Fock problem of the ion core is solved. The orbital energies and certain two-electron Coulomb matrix elements with respect to the molecular orbital basis are then used to construct an energy-dependent many-body correction to the Hartree-Fock mean field. This correction is derived from the Dyson equation satisfied by the one-particle Green's function. The method is applied to calculate Rydberg potential-energy curves of HCO. The presented data confirm and extend recent large-scale multireference configuration-interaction calculations and help develop a detailed theoretical description of the astrophysically important dissociative recombination of a low-energy electron with HCO(+). As further illustration of the utility of the method, the first ab initio calculations of the excited states of an electron bound to the guanidinium cation [C(NH(2))(3)](+) are reported.
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Affiliation(s)
- Sven Feuerbacher
- Theoretische Chemie, Physikalisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany
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27
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Geppert WD, Thomas RD, Ehlerding A, Hellberg F, Österdahl F, Hamberg M, Semaniak J, Zhaunerchyk V, Kaminska M, Källberg A, Paal A, Larsson M. Dissociative recombination branching ratios and their influence on interstellar clouds. ACTA ACUST UNITED AC 2005. [DOI: 10.1088/1742-6596/4/1/004] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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29
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Rosati RE, Johnsen R, Golde MF. Yield of electronically excited N2 molecules from the dissociative recombination of N2H+ with e-. J Chem Phys 2004; 120:8025-30. [PMID: 15267721 DOI: 10.1063/1.1695314] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Quantitative spectroscopic observations of the N2 first positive band system (N2(B 3Pig-A 3Sigmau+))/electron in a recombining N2H+ flowing-afterglow plasma indicate that a substantial fraction of the product N2 molecules are formed in one or more of the low-lying triplet states, B 3Pig, A 3Sigmau+, and W 3Deltau. The total measured N2(B-A) emission intensity from N2(B,v' > or = 1) is equivalent to a yield of (19 +/- 8)%. The effect of rapid collision-induced transitions between states of the triplet manifold is discussed..
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Affiliation(s)
- Richard E Rosati
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
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30
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Ojekull J, Andersson PU, Någård MB, Pettersson JBC, Derkatch AM, Neau A, Rosén S, Thomas R, Larsson M, Osterdahl F, Semaniak J, Danared H, Källberg A, af Ugglas M, Marković N. Dissociative recombination of NH4+ and ND4+ ions: Storage ring experiments andab initiomolecular dynamics. J Chem Phys 2004; 120:7391-9. [PMID: 15267649 DOI: 10.1063/1.1669388] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The dissociative recombination (DR) process of NH4+ and ND4+ molecular ions with free electrons has been studied at the heavy-ion storage ring CRYRING (Manne Siegbahn Laboratory, Stockholm University). The absolute cross sections for DR of NH4+ and ND4+ in the collision energy range 0.001-1 eV are reported, and thermal rate coefficients for the temperature interval from 10 to 2000 K are calculated from the experimental data. The absolute cross section for NH4+ agrees well with earlier work and is about a factor of 2 larger than the cross section for ND4+. The dissociative recombination of NH4+ is dominated by the product channels NH3+H (0.85+/-0.04) and NH2+2H (0.13+/-0.01), while the DR of ND4+ mainly results in ND3+D (0.94+/-0.03). Ab initio direct dynamics simulations, based on the assumption that the dissociation dynamics is governed by the neutral ground-state potential energy surface, suggest that the primary product formed in the DR process is NH3+H. The ejection of the H atom is direct and leaves the NH3 molecule highly vibrationally excited. A fraction of the excited ammonia molecules may subsequently undergo secondary fragmentation forming NH2+H. It is concluded that the model results are consistent with gross features of the experimental results, including the sensitivity of the branching ratio for the three-body channel NH2+2H to isotopic exchange.
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Affiliation(s)
- J Ojekull
- Department of Chemistry, Atmospheric Science, Göteborg University, SE-412 96 Göteborg, Sweden
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31
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Geppert WD, Thomas R, Hellberg F, Ehlerding A, Österdahl F, af Ugglas M, Larsson M. Dissociative recombination of N2OD+. Phys Chem Chem Phys 2004. [DOI: 10.1039/b403461a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Geppert WD, Thomas R, Ehlerding A, Semaniak J, Osterdahl F, af Ugglas M, Djurić N, Paál A, Larsson M. Extraordinary branching ratios in astrophysically important dissociative recombination reactions. Faraday Discuss 2004; 127:425-37. [PMID: 15471358 DOI: 10.1039/b314005a] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Branching ratios of the dissociative recombination reactions of the astrophysically relevant ions DCO+, N2H+ and DOCO+ (as substitute for HOCO+) have been measured using the CRYRING storage ring at the Manne Siegbahn Laboratory at the University of Stockholm, Sweden. For DCO+, the channel leading to D and CO was by far the most important one (branching ratio 0.88), only small contributions of the CD + O and OD + C product pathways (branching ratios 0.06 each) were recorded. In the case of N2H+ the surprising result of a break-up of the N-N bond to N and NH (branching ratio 0.64) was found with the branching ratio of the N2 + H product channel therefore displaying a branching ratio of only 0.36. In the case of DOCO+, the three-body break-up into D + O + CO dominated (branching ratio 0.68), whereas the contribution of the CO2 + H channel was only minute (0.05). The remaining share (branching ratio 0.27) was taken by the pathway leading to OH + CO. For the dissociative recombination of N2H+ and DOCO+ also absolute reaction cross sections were obtained in the collisional energy range between 0 and 1 eV. From these cross sections it was possible to work out the thermal rate constants, which were found to be k(T) = 1.0+/-0.1 x 10(-7) (T/300 K)(-0.51+/-0.02) cm3 s(-1) and k(T) = 1.2+/-0.1 x 10(-6) (T/300 K)(-0.64+/-0.02) cm3 S(-1) for N2H+ and DOCO+, respectively.
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Affiliation(s)
- Wolf D Geppert
- Department of Physics, Stockholm University, Alba Nova, SE-106 91 Stockholm, Sweden
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33
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Petrik NG, Kimmel GA. Electron-stimulated reactions at the interfaces of amorphous solid water films driven by long-range energy transfer from the bulk. PHYSICAL REVIEW LETTERS 2003; 90:166102. [PMID: 12731983 DOI: 10.1103/physrevlett.90.166102] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2002] [Indexed: 05/24/2023]
Abstract
The electron-stimulated production of D2 from amorphous solid D2O deposited on Pt(111) is investigated as a function of film thickness. The D2 yield has two components that have distinct reaction kinetics. Using isotopically layered films of H2O and D2O demonstrates that the D2 is produced in reactions that occur at both the Pt/amorphous solid water (ASW) interface and the ASW/vacuum interface, but not in the bulk. The energy for the reactions, however, is absorbed in the bulk of the films and electronic excitations diffuse to the interfaces where they drive the reactions.
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Affiliation(s)
- Nikolay G Petrik
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Mail Stop K8-88, P.O. Box 999, Richland, Washington 99352, USA
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Neau A, Al Khalili A, Rosén S, Le Padellec A, Derkatch AM, Shi W, Vikor L, Larsson M, Semaniak J, Thomas R, Någård MB, Andersson K, Danared H, af Ugglas M. Dissociative recombination of D3O+ and H3O+: Absolute cross sections and branching ratios. J Chem Phys 2000. [DOI: 10.1063/1.481979] [Citation(s) in RCA: 153] [Impact Index Per Article: 6.4] [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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Skrzypkowski MP, Gougousi T, Johnsen R, Golde MF. Measurement of the absolute yield of CO(a 3Π)+O products in the dissociative recombination of CO2+ ions with electrons. J Chem Phys 1998. [DOI: 10.1063/1.476267] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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38
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Ion-molecule chemistry in interstellar clouds. ACTA ACUST UNITED AC 1998. [DOI: 10.1016/s1071-9687(98)80003-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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39
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Abstract
The development of heavy-ion storage-cooler rings for atomic physics has made it possible to produce high-quality beams of molecular ions that are internally cold. The stored molecular-ion beam is immersed in a cold electron bath, which gives a beam of low divergence and small cross-sectional area. The electron cooler also serves as a target for electron-molecular ion collision experiments. This allows the study of dissociative recombination of cold molecules with respect to cross sections, branching ratios, and angular distributions at an unprecedented luminosity.
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Affiliation(s)
- M Larsson
- Department of Physics, Stockholm University, PO Box 6730, Stockholm, S-113 85 Sweden.
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40
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Gougousi T, Johnsen R, Golde MF. Yield determination of OH(v=0,1) radicals produced by the electron-ion recombination of H3O+ ions. J Chem Phys 1997. [DOI: 10.1063/1.474586] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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Gougousi T, Johnsen R, Golde MF. Yield determination of OH (v=0,1) radicals produced by the electron-ion recombination of protonated molecules. J Chem Phys 1997. [DOI: 10.1063/1.474587] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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42
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BUTLER BJEFFERYM, BABCOCK LUCIAM, ADAMS NIGELG. Effects of deuteration on vibrational excitation in the products of the electron recombination of HCO+ and N2H+. Mol Phys 1997. [DOI: 10.1080/002689797171760] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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43
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Andersen LH, Heber O, Kella D, Pedersen HB, Vejby-Christensen L, Zajfman D. Production of Water Molecules from Dissociative Recombination of H3O + with Electrons. PHYSICAL REVIEW LETTERS 1996; 77:4891-4894. [PMID: 10062661 DOI: 10.1103/physrevlett.77.4891] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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44
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45
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Swarm Techniques. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s0076-695x(08)60660-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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46
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Kimmel GA, Orlando TM, Vézina C, Sanche L. Low‐energy electron‐stimulated production of molecular hydrogen from amorphous water ice. J Chem Phys 1994. [DOI: 10.1063/1.468430] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Adams NG. Afterglow techniques with spectroscopic detection for determining the rate coefficients and products of dissociative electron—ion recombination. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0168-1176(93)03917-b] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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48
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49
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Sonnenfroh DM, Caledonia GE, Lurie J. Emission from OH(A) produced in the dissociative recombination of H2O+ with electrons. J Chem Phys 1993. [DOI: 10.1063/1.464115] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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50
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Canosa A, Gomet JC, Rowe BR, Mitchell JBA, Queffelec JL. Further measurements of the H+3(v=0,1,2) dissociative recombination rate coefficient. J Chem Phys 1992. [DOI: 10.1063/1.463282] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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