The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
P. C. Cosby - One of the best experts on this subject based on the ideXlab platform.
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Electron‐Impact dissociation of oxygen
The Journal of Chemical Physics, 1993Co-Authors: P. C. CosbyAbstract:The Electron‐Impact dissociation of O2 to form two oxygen atoms is observed in a crossed beam experiment at Electron energies between 13.5 and 198.5 eV. Detection of the correlated dissociation fragments with a time and position sensitive detector permits detection of both ground and excited state fragments, but excludes interference from dissociative ionization products. The observed translational energy releases in the O2 dissociation are consistent with production of O(1D)+O(3P) fragments following Electron Impact excitation to the B 3Σu−, B’ 3Σu−, and 2 3Πu states, and production of O(3P)+O(3P) fragments from excitation to the (unresolved) c 1Σu−, A’ 3Δu, and A 3Σu+ states. Absolute cross sections for the Electron Impact dissociation of O2 are measured.
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Electron‐Impact dissociation of nitrogen
The Journal of Chemical Physics, 1993Co-Authors: P. C. CosbyAbstract:The Electron‐Impact dissociation of N2 to form two nitrogen atoms is observed in a crossed beam experiment at Electron energies between 18.5 and 148.5 eV. Detection of the correlated dissociation fragments with a time and position sensitive detector permits detection of both ground and excited state fragments, but excludes interference from dissociative ionization products. The observed translational energy releases in the N2 dissociation are consistent with predissociation to N(2D)+N(4S) fragments as the primary dissociation mechanism. Absolute cross sections for the Electron Impact dissociation are measured and compared with previous measurements. Recommended values of this cross section are given for Electron‐Impact energies between 10 and 200 eV.
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Electron‐Impact dissociation of carbon monoxide
The Journal of Chemical Physics, 1993Co-Authors: P. C. CosbyAbstract:The Electron‐Impact dissociation of CO to form C and O atoms is observed in a crossed beam experiment at Electron energies between the dissociation threshold (14 eV) and 198.5 eV. The center‐of‐mass energy released in the dissociation of individual molecules is explicitly measured using a position and time sensitive detector for the correlated neutral fragments. The observed energy release distribution is found to be highly structured, reflecting Electron‐Impact excitation to Rydberg states converging to CO+(X 2Σ+) which predissociate to ground state atoms. Little or no dissociation is observed from states above the first ionization limit. Total Electron Impact dissociation cross sections, exclusive of dissociative ionization contributions, and partial cross sections for the dissociative excitation of specific CO Electronic states are presented.
M. S. Pindzola - One of the best experts on this subject based on the ideXlab platform.
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Electron-Impact double ionization of the H2 molecule
Journal of Physics B: Atomic Molecular and Optical Physics, 2018Co-Authors: M. S. Pindzola, James Colgan, B. M. MclaughlinAbstract:A time-dependent close-coupling method in spherical polar coordinates is developed to calculate the Electron-Impact double ionization of the H2 molecule. The full wavefunction is represented by an expansion in products of six-dimensional radial-angular numerical functions and three analytic rotational functions. For an incident energy of 100 eV, the total cross section is calculated for the Electron-Impact double ionization of H2 and compared with experiment.
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Electron-Impact Ionization of C+ and C3+
Journal of Physics: Conference Series, 2012Co-Authors: M. S. Pindzola, C P Ballance, S D LochAbstract:Non-perturbative close-coupling and perturbative distorted-wave methods are used to calculate Electron-Impact ionization cross sections for the excited states of C+ and C3+.
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Electron-Impact single and double ionization of helium
Physical Review A, 2004Co-Authors: M. S. Pindzola, James Colgan, Francis Robicheaux, M. C. Witthoeft, J. A. LudlowAbstract:Electron-Impact ionization cross sections for helium are calculated using time-dependent close-coupling theory. The total wave function for the three Electron system is expanded in nine dimensions, where three dimensions are represented on a radial lattice and a coupled channels expansion is used to represent the other six dimensions. Collision cross sections are obtained by t{yields}{infinity} projection onto fully antisymmetric spatial and spin functions, with care as to orthogonality of different representations. Cross sections are also obtained using time-independent first- and second-order perturbative distorted-wave theory. Total cross sections are calculated at incident energies above the double ionization threshold for Electron-Impact single ionization leaving He{sup +} in the 1s, 2s, and 2p states and for Electron-Impact double ionization. Both the single ionization cross section, leaving He{sup +} in the 1s ground state, and the double ionization cross section are in excellent agreement with previous absolute experimental measurements.
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Electron-Impact excitation of lithium
Physical Review A, 2001Co-Authors: D. C. Griffin, Dario M. Mitnik, J. Colgan, M. S. PindzolaAbstract:The results of R-matrix with pseudostates (RMPS) and time-dependent close-coupling (TDCC) calculations of Electron-Impact excitation in Li are presented. We included 55 terms in the RMPS close-coupling expansion, of which nine are spectroscopic and 46 are pseudostates. The two-Electron radial wave functions generated from earlier TDCC calculations for ionization from the ground state of Li by Colgan [Phys. Rev. A 63, 062709 (2001)] are employed to determine the TDCC excitation cross sections. The RMPS and TDCC cross sections for transitions from 1s{sup 2}2s to 1s{sup 2}2p, 1s{sup 2}3l, and 1s{sup 2}4l are compared to each other and to cross sections determined from our R-matrix calculation without pseudostates, the convergent close-coupling calculations presented by Schweinzer [At. Data Nucl. Data Tables 72, 239 (1999)], the coupled-channel optical calculations of Bray [Phys. Rev. A 47, 1101 (1993)], and experimental measurements. These results indicate that coupling to the target continuum has a significant effect on Electron-Impact excitation in this atom; this increases with the principal quantum number of the excited term, and is large for transitions to 1s{sup 2}4l.
James Colgan - One of the best experts on this subject based on the ideXlab platform.
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Electron-Impact double ionization of the H2 molecule
Journal of Physics B: Atomic Molecular and Optical Physics, 2018Co-Authors: M. S. Pindzola, James Colgan, B. M. MclaughlinAbstract:A time-dependent close-coupling method in spherical polar coordinates is developed to calculate the Electron-Impact double ionization of the H2 molecule. The full wavefunction is represented by an expansion in products of six-dimensional radial-angular numerical functions and three analytic rotational functions. For an incident energy of 100 eV, the total cross section is calculated for the Electron-Impact double ionization of H2 and compared with experiment.
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Inner-shell Electron-Impact ionization of neutral atoms
Physical Review A, 2006Co-Authors: James Colgan, Christopher J. Fontes, Hong Lin ZhangAbstract:A study of inner-shell Electron-Impact ionization of heavy neutral atoms is presented. A relativistic distorted-wave method is used to calculate K-shell ionization of neutral Mn, Fe, Ni, and Cu, and also the L-shell ionization of neutral W. These calculations are compared with measurements made by Electron-Impact ionization from a thin target of the atomic species in question. Good agreement is found between the calculations and measurements.
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Electron-Impact single and double ionization of helium
Physical Review A, 2004Co-Authors: M. S. Pindzola, James Colgan, Francis Robicheaux, M. C. Witthoeft, J. A. LudlowAbstract:Electron-Impact ionization cross sections for helium are calculated using time-dependent close-coupling theory. The total wave function for the three Electron system is expanded in nine dimensions, where three dimensions are represented on a radial lattice and a coupled channels expansion is used to represent the other six dimensions. Collision cross sections are obtained by t{yields}{infinity} projection onto fully antisymmetric spatial and spin functions, with care as to orthogonality of different representations. Cross sections are also obtained using time-independent first- and second-order perturbative distorted-wave theory. Total cross sections are calculated at incident energies above the double ionization threshold for Electron-Impact single ionization leaving He{sup +} in the 1s, 2s, and 2p states and for Electron-Impact double ionization. Both the single ionization cross section, leaving He{sup +} in the 1s ground state, and the double ionization cross section are in excellent agreement with previous absolute experimental measurements.
Donald E. Shemansky - One of the best experts on this subject based on the ideXlab platform.
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Analysis of Electron Impact ionization properties of methane
Journal of Geophysical Research, 2006Co-Authors: Donald E. ShemanskyAbstract:[1] Published experimental photon and Electron Impact ionization cross sections of CH4 have been reviewed and analyzed. Absolute partial ionization oscillator strengths (fij) for CH4+, CH3+, CH2+, CH+, H+, and H2+ have been obtained. Electron Impact ionization cross sections are recommended based on agreement between the oscillator strength values derived from photoionization and Electron Impact measurements. Analytic functions for cross sections of CH4+, CH3+, CH2+, CH+, C+, H2+, and H+ produced by Electron Impact ionization of CH4 are established. The derived excitation cross-section functions are accurate from threshold to Impact energies limited by relativistic effects (i.e., E < 0.2 MeV). The cross sections examined here are important for modeling Titan ionospheric chemistry.
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Analysis of Electron Impact ionization properties of methane
Journal of Geophysical Research, 2006Co-Authors: Donald E. ShemanskyAbstract:[1] Published experimental photon and Electron Impact ionization cross sections of CH4 have been reviewed and analyzed. Absolute partial ionization oscillator strengths (fij) for CH4+, CH3+, CH2+, CH+, H+, and H2+ have been obtained. Electron Impact ionization cross sections are recommended based on agreement between the oscillator strength values derived from photoionization and Electron Impact measurements. Analytic functions for cross sections of CH4+, CH3+, CH2+, CH+, C+, H2+, and H+ produced by Electron Impact ionization of CH4 are established. The derived excitation cross-section functions are accurate from threshold to Impact energies limited by relativistic effects (i.e., E < 0.2 MeV). The cross sections examined here are important for modeling Titan ionospheric chemistry.
A. Müller - One of the best experts on this subject based on the ideXlab platform.
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Electron-Impact ionization of tungsten ions
Journal of Physics: Conference Series, 2015Co-Authors: Alexander Borovik, D. Schury, B. Ebinger, K. Spruck, M F Gharaibeh, J Rausch, Stefan Schippers, A. Becker, A. MüllerAbstract:Electron-Impact ionization of tungsten ions has been measured in the energy range from threshold up to 1000 eV. Configuration-averaged distorted wave calculations were used to explain the experimental data.
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Electron-Impact single and double ionization of W17 +
Journal of Physics B: Atomic Molecular and Optical Physics, 2011Co-Authors: J Rausch, K. Spruck, A. Becker, J Hellhund, A Borovik, K Huber, S Schippers, A. MüllerAbstract:A crossed-beams setup was used to measure cross sections for Electron-Impact single and double ionization of W 17+ ions. Absolute data and high-resolution scan spectra were obtained at collision energies ranging from threshold up to 1000 eV. Comparison of the experimental results with theoretical calculations for direct ionization suggests substantial contributions of excitation-autoionization processes to Electron-Impact single ionization of W 17+.
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Electron Impact single and double ionization of w17
Journal of Physics B, 2011Co-Authors: J Rausch, K. Spruck, A. Becker, J Hellhund, A Borovik, K Huber, S Schippers, A. MüllerAbstract:A crossed-beam setup was used to measure cross sections for Electron-Impact single and double ionization of W17 + ions. Absolute data and high-resolution scan spectra were obtained at collision energies ranging from threshold up to 1000eV. A comparison of the experimental results with theoretical calculations for direct ionization suggests substantial contributions of excitation–autoionization processes to Electron-Impact single ionization of W17 +.