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M. S. Pindzola - One of the best experts on this subject based on the ideXlab platform.

  • Electron Impact Excitation of the ne2 o like ion
    Journal of Physics: Conference Series, 2012
    Co-Authors: S. D. Loch, J. A. Ludlow, M. S. Pindzola, B M Mclaughlin, E Landi, C. P. Ballance
    Abstract:

    A large-scale 554 level R-matrix Intermediate Coupling Frame Transformation (ICFT) calculation is presented to provide a comprehensive Electron-Impact Excitation data set for all transitions to higher n shells.

  • Breit?Pauli R-matrix Electron-Impact Excitation calculations along the argon isonuclear sequence
    Journal of Physics B, 2010
    Co-Authors: J. A. Ludlow, C. P. Ballance, Stuart Loch, M. S. Pindzola
    Abstract:

    Electron-Impact Excitation of argon ions is a vital component in the modelling of fusion tokamak experiments. Currently the available Electron-Impact Excitation rates for the argon isonuclear sequence are a collection of isolated calculations carried out within various theoretical scattering models. With the development of our parallel suite of Breit?Pauli codes and the accessibility of massively parallel architectures, there was the opportunity to calculate the entire argon isonuclear sequence and provide a single, comprehensive and complete Excitation data set. These data will subsequently be archived as Maxwellian averaged rate coefficients. We report on Breit?Pauli R-matrix Electron-Impact Excitation calculations that have been performed for Ar3+, Ar4+, Ar5+, Ar7+, Ar8+, Ar10+, Ar11+, Ar12+, Ar13+, Ar14+ and Ar17+. Together with existing R-matrix calculations, this completes the generation of Excitation data for the argon isonuclear sequence.

  • Breit-Pauli R-matrix Electron-Impact Excitation calculations along the argon isonuclear sequence
    Journal of Physics B: Atomic Molecular and Optical Physics, 2010
    Co-Authors: J. A. Ludlow, C. P. Ballance, S. D. Loch, M. S. Pindzola
    Abstract:

    Electron-Impact Excitation of argon ions is a vital component in the modelling of fusion tokamak experiments. Currently the available Electron-Impact Excitation rates for the argon isonuclear sequence are a collection of isolated calculations carried out within various theoretical scattering models. With the development of our parallel suite of Breit-Pauli codes and the accessibility of massively parallel architectures, there was the opportunity to calculate the entire argon isonuclear sequence and provide a single, comprehensive and complete Excitation data set. These data will subsequently be archived as Maxwellian averaged rate coefficients. We report on Breit-Pauli R-matrix Electron-Impact Excitation calculations that have been performed for Ar 3+, Ar4+, Ar5+, Ar7+, Ar 8+, Ar10+, Ar11+, Ar12+, Ar 13+, Ar14+ and Ar17+. Together with existing R-matrix calculations, this completes the generation of Excitation data for the argon isonuclear sequence. © 2010 IOP Publishing Ltd.

  • Electron-Impact Excitation of beryllium and its ions
    Physical Review A, 2003
    Co-Authors: Connor Ballance, Stuart Loch, D. C. Griffin, James Colgan, M. S. Pindzola
    Abstract:

    Inelastic Electron scattering from light atomic species is of fundamental importance and has significant applications in fusion-plasma modeling. Therefore, it is of interest to apply advanced nonperturbative, close-coupling methods to the determination of Electron-Impact Excitation for these atoms. Here we present the results of R matrix with pseudostate (RMPS) calculations of Electron-Impact Excitation cross sections through the n=4 terms in Be, Be{sup +}, Be{sup 2+}, and Be{sup 3+}. In order to determine the effects of coupling of the bound states to the target continuum in these species, we compare the RMPS results with those from standard R-matrix calculations. In addition, we have performed time-dependent close-coupling calculations for Excitation from the ground and the metastable terms of Be{sup +} and the metastable term of Be{sup 3+}. In general, these results are found to agree with those from our RMPS calculations. The full set of data resulting from this work is now available on the Oak Ridge National Laboratory Controlled Fusion Atomic Data Center web site, and will be employed for collisional-radiative modeling of Be in magnetically confined plasmas.

  • Electron-Impact Excitation of lithium
    Physical Review A, 2001
    Co-Authors: D. C. Griffin, Dario M. Mitnik, James Colgan, M. S. Pindzola
    Abstract:

    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.

C. P. Ballance - One of the best experts on this subject based on the ideXlab platform.

  • Electron Impact Excitation of the ne2 o like ion
    Journal of Physics: Conference Series, 2012
    Co-Authors: S. D. Loch, J. A. Ludlow, M. S. Pindzola, B M Mclaughlin, E Landi, C. P. Ballance
    Abstract:

    A large-scale 554 level R-matrix Intermediate Coupling Frame Transformation (ICFT) calculation is presented to provide a comprehensive Electron-Impact Excitation data set for all transitions to higher n shells.

  • Breit?Pauli R-matrix Electron-Impact Excitation calculations along the argon isonuclear sequence
    Journal of Physics B, 2010
    Co-Authors: J. A. Ludlow, C. P. Ballance, Stuart Loch, M. S. Pindzola
    Abstract:

    Electron-Impact Excitation of argon ions is a vital component in the modelling of fusion tokamak experiments. Currently the available Electron-Impact Excitation rates for the argon isonuclear sequence are a collection of isolated calculations carried out within various theoretical scattering models. With the development of our parallel suite of Breit?Pauli codes and the accessibility of massively parallel architectures, there was the opportunity to calculate the entire argon isonuclear sequence and provide a single, comprehensive and complete Excitation data set. These data will subsequently be archived as Maxwellian averaged rate coefficients. We report on Breit?Pauli R-matrix Electron-Impact Excitation calculations that have been performed for Ar3+, Ar4+, Ar5+, Ar7+, Ar8+, Ar10+, Ar11+, Ar12+, Ar13+, Ar14+ and Ar17+. Together with existing R-matrix calculations, this completes the generation of Excitation data for the argon isonuclear sequence.

  • Breit-Pauli R-matrix Electron-Impact Excitation calculations along the argon isonuclear sequence
    Journal of Physics B: Atomic Molecular and Optical Physics, 2010
    Co-Authors: J. A. Ludlow, C. P. Ballance, S. D. Loch, M. S. Pindzola
    Abstract:

    Electron-Impact Excitation of argon ions is a vital component in the modelling of fusion tokamak experiments. Currently the available Electron-Impact Excitation rates for the argon isonuclear sequence are a collection of isolated calculations carried out within various theoretical scattering models. With the development of our parallel suite of Breit-Pauli codes and the accessibility of massively parallel architectures, there was the opportunity to calculate the entire argon isonuclear sequence and provide a single, comprehensive and complete Excitation data set. These data will subsequently be archived as Maxwellian averaged rate coefficients. We report on Breit-Pauli R-matrix Electron-Impact Excitation calculations that have been performed for Ar 3+, Ar4+, Ar5+, Ar7+, Ar 8+, Ar10+, Ar11+, Ar12+, Ar 13+, Ar14+ and Ar17+. Together with existing R-matrix calculations, this completes the generation of Excitation data for the argon isonuclear sequence. © 2010 IOP Publishing Ltd.

  • Electron Impact Excitation of ar 2
    Astronomy and Astrophysics, 2009
    Co-Authors: J Munoz M Burgos, C. P. Ballance, S. D. Loch, R F Boivin
    Abstract:

    Context. Emission from Ar III is seen in planetary nebulae, in H II regions, and from laboratory plasmas. The analysis of such spectra requires accurate Electron Impact Excitation data. Aims. The aim of this work is to improve the Electron Impact Excitation data available for Ar 2+ , for application in studies of planetary nebulae and laboratory plasma spectra. The effects of the new data on diagnostic line ratios are also studied. Methods. Electron-Impact Excitation collision strengths have been calculated using the R-Matrix Intermediate-Coupling FrameTransformation method and the R-Matrix Breit-Pauli method. Excitation cross sections are calculated between all levels of the configurations 3s 2 3p 4 ,3 s3p 5 ,3 p 6 ,3 p 5 3d, and 3s 2 3p 3 nl (3d ≤ nl ≤ 5s). Maxwellian effective collision strengths are generated from the collision strength data. Results. Good agreement is found in the collision strengths calculated using the two R-Matrix methods. The collision strengths are compared with literature values for transitions within the 3s 2 3p 4 configuration. The new data has a small effect on Te values obtained from the I(λ7135 A + λ7751 A)/I(λ5192 A) line ratio, and a larger effect on the Ne values obtained from the I(λ7135 A)/I(λ9 μm) line ratio. The final effective collision strength data is archived online � .

  • Intermediate-coupling R-matrix calculations of Electron-Impact Excitation of Fe5+
    Journal of Physics B, 2008
    Co-Authors: C. P. Ballance, D. C. Griffin
    Abstract:

    For applications to laboratory and astrophysical plasmas, there is a great need for accurate Electron-Impact Excitation data between individual levels in the lower charge-state ions of iron. Recently, we have reported on the first intermediate-coupling R-matrix calculation of Electron-Impact Excitation in Fe4+, in which the close-coupling expansion of the target included levels from both ground and excited configurations (Ballance et al 2007 J. Phys. B: At. Mol. Opt. Phys. 40 F327, 2008 Europhys. News 39 14). In this paper, we present the results of two large intermediate-coupling Dirac R-matrix calculations of Electron-Impact Excitation of Fe5+. The results from the two calculations, which differ only in the configuration–interaction expansions of the target, are compared. These comparisons provide some indication of the accuracy of the calculations and the resulting data should be useful in modelling plasmas containing iron.

J. A. Ludlow - One of the best experts on this subject based on the ideXlab platform.

  • Electron Impact Excitation of the ne2 o like ion
    Journal of Physics: Conference Series, 2012
    Co-Authors: S. D. Loch, J. A. Ludlow, M. S. Pindzola, B M Mclaughlin, E Landi, C. P. Ballance
    Abstract:

    A large-scale 554 level R-matrix Intermediate Coupling Frame Transformation (ICFT) calculation is presented to provide a comprehensive Electron-Impact Excitation data set for all transitions to higher n shells.

  • Breit?Pauli R-matrix Electron-Impact Excitation calculations along the argon isonuclear sequence
    Journal of Physics B, 2010
    Co-Authors: J. A. Ludlow, C. P. Ballance, Stuart Loch, M. S. Pindzola
    Abstract:

    Electron-Impact Excitation of argon ions is a vital component in the modelling of fusion tokamak experiments. Currently the available Electron-Impact Excitation rates for the argon isonuclear sequence are a collection of isolated calculations carried out within various theoretical scattering models. With the development of our parallel suite of Breit?Pauli codes and the accessibility of massively parallel architectures, there was the opportunity to calculate the entire argon isonuclear sequence and provide a single, comprehensive and complete Excitation data set. These data will subsequently be archived as Maxwellian averaged rate coefficients. We report on Breit?Pauli R-matrix Electron-Impact Excitation calculations that have been performed for Ar3+, Ar4+, Ar5+, Ar7+, Ar8+, Ar10+, Ar11+, Ar12+, Ar13+, Ar14+ and Ar17+. Together with existing R-matrix calculations, this completes the generation of Excitation data for the argon isonuclear sequence.

  • Breit-Pauli R-matrix Electron-Impact Excitation calculations along the argon isonuclear sequence
    Journal of Physics B: Atomic Molecular and Optical Physics, 2010
    Co-Authors: J. A. Ludlow, C. P. Ballance, S. D. Loch, M. S. Pindzola
    Abstract:

    Electron-Impact Excitation of argon ions is a vital component in the modelling of fusion tokamak experiments. Currently the available Electron-Impact Excitation rates for the argon isonuclear sequence are a collection of isolated calculations carried out within various theoretical scattering models. With the development of our parallel suite of Breit-Pauli codes and the accessibility of massively parallel architectures, there was the opportunity to calculate the entire argon isonuclear sequence and provide a single, comprehensive and complete Excitation data set. These data will subsequently be archived as Maxwellian averaged rate coefficients. We report on Breit-Pauli R-matrix Electron-Impact Excitation calculations that have been performed for Ar 3+, Ar4+, Ar5+, Ar7+, Ar 8+, Ar10+, Ar11+, Ar12+, Ar 13+, Ar14+ and Ar17+. Together with existing R-matrix calculations, this completes the generation of Excitation data for the argon isonuclear sequence. © 2010 IOP Publishing Ltd.

S. D. Loch - One of the best experts on this subject based on the ideXlab platform.

  • Electron Impact Excitation of the ne2 o like ion
    Journal of Physics: Conference Series, 2012
    Co-Authors: S. D. Loch, J. A. Ludlow, M. S. Pindzola, B M Mclaughlin, E Landi, C. P. Ballance
    Abstract:

    A large-scale 554 level R-matrix Intermediate Coupling Frame Transformation (ICFT) calculation is presented to provide a comprehensive Electron-Impact Excitation data set for all transitions to higher n shells.

  • Breit-Pauli R-matrix Electron-Impact Excitation calculations along the argon isonuclear sequence
    Journal of Physics B: Atomic Molecular and Optical Physics, 2010
    Co-Authors: J. A. Ludlow, C. P. Ballance, S. D. Loch, M. S. Pindzola
    Abstract:

    Electron-Impact Excitation of argon ions is a vital component in the modelling of fusion tokamak experiments. Currently the available Electron-Impact Excitation rates for the argon isonuclear sequence are a collection of isolated calculations carried out within various theoretical scattering models. With the development of our parallel suite of Breit-Pauli codes and the accessibility of massively parallel architectures, there was the opportunity to calculate the entire argon isonuclear sequence and provide a single, comprehensive and complete Excitation data set. These data will subsequently be archived as Maxwellian averaged rate coefficients. We report on Breit-Pauli R-matrix Electron-Impact Excitation calculations that have been performed for Ar 3+, Ar4+, Ar5+, Ar7+, Ar 8+, Ar10+, Ar11+, Ar12+, Ar 13+, Ar14+ and Ar17+. Together with existing R-matrix calculations, this completes the generation of Excitation data for the argon isonuclear sequence. © 2010 IOP Publishing Ltd.

  • Electron Impact Excitation of ar 2
    Astronomy and Astrophysics, 2009
    Co-Authors: J Munoz M Burgos, C. P. Ballance, S. D. Loch, R F Boivin
    Abstract:

    Context. Emission from Ar III is seen in planetary nebulae, in H II regions, and from laboratory plasmas. The analysis of such spectra requires accurate Electron Impact Excitation data. Aims. The aim of this work is to improve the Electron Impact Excitation data available for Ar 2+ , for application in studies of planetary nebulae and laboratory plasma spectra. The effects of the new data on diagnostic line ratios are also studied. Methods. Electron-Impact Excitation collision strengths have been calculated using the R-Matrix Intermediate-Coupling FrameTransformation method and the R-Matrix Breit-Pauli method. Excitation cross sections are calculated between all levels of the configurations 3s 2 3p 4 ,3 s3p 5 ,3 p 6 ,3 p 5 3d, and 3s 2 3p 3 nl (3d ≤ nl ≤ 5s). Maxwellian effective collision strengths are generated from the collision strength data. Results. Good agreement is found in the collision strengths calculated using the two R-Matrix methods. The collision strengths are compared with literature values for transitions within the 3s 2 3p 4 configuration. The new data has a small effect on Te values obtained from the I(λ7135 A + λ7751 A)/I(λ5192 A) line ratio, and a larger effect on the Ne values obtained from the I(λ7135 A)/I(λ9 μm) line ratio. The final effective collision strength data is archived online � .

Rajesh Srivastava - One of the best experts on this subject based on the ideXlab platform.

  • Electron Impact Excitation of tin
    European Physical Journal D, 2017
    Co-Authors: Lalita Sharma, Swati Bharti, Rajesh Srivastava
    Abstract:

    We study the Electron Impact Excitation of the fine-structure levels of the ground state configuration 5p 2 to the excited states of the configuration 5p6s in tin atom. These calculations have been carried out in the j j coupling scheme using the relativistic distorted-wave method. Results for differential cross section are reported at incident Electron energies 20, 50, 80 and 100 eV while integrated cross sections are presented in the incident Electron energy range of 5 to 100 eV.

  • Electron Impact Excitation of Fe-like Tungsten Ion
    2016
    Co-Authors: Priti, Lalita Sharma, Dipti, Rajesh Srivastava
    Abstract:

    Electron Impact Excitation of Fe-like tungsten ion has been studied using relativistic distorted wave theory. Cross-sections are obtained in the energy range upto 20 keV and their fitting is also provided for their potential application in plasma modeling. Polarization of the photon emission following the decay of the excited states is also analysed.

  • Fully Relativistic Electron Impact Excitation Cross-Section and Polarization for Tungsten Ions
    Atoms, 2015
    Co-Authors: Priti, Lalita Sharma, Dipti, Rajesh Srivastava
    Abstract:

    Electron Impact Excitation of highly charged tungsten ions in the framework of a fully relativistic distorted wave approach is considered in this paper. Calculations of Electron Impact Excitation cross-sections for the M- and L-shell transitions in the tungsten ions Wn+ (n = 44–66) and polarization of the decay of photons from the excited tungsten ions are briefly reviewed and discussed. New calculations in the wide range of incident Electron energies are presented for M-shell transitions in the K-like through Ne-like tungsten ions.

  • Electron Impact Excitation from the initially excited cadmium atom
    International Journal of Mass Spectrometry, 2014
    Co-Authors: Lalita Sharma, Rajesh Srivastava, Allan Stauffer
    Abstract:

    Abstract Recently applied relativistic distorted wave approximation theory to study Electron Impact Excitation from the ground states of two valence Electron atoms viz. Zn and Yb has been extended to study the Electron Impact Excitation of Cd atom from its lowest excited fine structure states. Results have been calculated for differential as well as integrated cross sections. For comparison, the integrated cross section results are also calculated using available flexible atomic code. Both the calculations are then compared with the available experimental results. In general, reasonable agreement among the theoretical and experimental results has been found.

  • Electron Impact Excitation of singly charged metal ions
    Physical Review A, 2011
    Co-Authors: Lalita Sharma, Rajesh Srivastava, A Surzhykov, S Fritzsche
    Abstract:

    Fully relativistic distorted-wave theory has been applied to study the Electron-Impact Excitation of the ns{sub 1/2}-np{sub 1/2} and ns{sub 1/2}-np{sub 3/2} resonance transitions of singly charged metal ions with one valence Electron, viz., Mg{sup +} (n=3), Ca{sup +} (n=4), Zn{sup +} (n=4), Cd{sup +} (n=5), and Ba{sup +} (n=6). Calculations are performed in the range of incident Electron energies up to 300 eV for differential and integrated cross sections as well as for the linear polarization of the photon emissions following the decay of excited np{sub 3/2} states. Results are compared with the available experimental data and previous nonrelativistic theoretical calculations. Moreover, analytic fits to our integrated cross sections are provided for potential applications in modeling plasma sources and environments.