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Your search keyword '"Spruck, K."' showing total 3 results
Start Over Author "Spruck, K." Topic ion recombination
3 results on '"Spruck, K."'

1. Recombination of W 18 + ions with electrons: Absolute rate coefficients from a storage-ring experiment and from theoretical calculations

Author

Spruck, K., Badnell, N. R., Krantz, C., Novotny, Oldrich, Becker, A., Bernhardt, D., Grieser, M., Hahn, Michael, Repnow, R., Savin, Daniel Wolf, Wolf, A., Muller, A., and Schippers, S.

Subjects
Storage rings, Physics::Plasma Physics, Ion recombination, Astrophysics, Tungsten ions, Electron impact ionization
Abstract

We present experimentally measured and theoretically calculated rate coefficients for the electron-ion recombination of W 18 + ( [ Kr ] 4 d 10 4 f 10 ) forming W 17 + . At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping recombination resonances. In the temperature range where the fractional abundance of W 18 + is expected to peak in a fusion plasma, the experimentally derived Maxwellian recombination rate coefficient is 5 to 10 times larger than that which is currently recommended for plasma modeling. The complexity of the atomic structure of the open- 4 f system under study makes the theoretical calculations extremely demanding. Nevertheless, the results of the present Breit-Wigner partitioned dielectronic recombination calculations agree reasonably well with the experimental findings. This also gives confidence in the ability of the theory to generate sufficiently accurate atomic data for the plasma modeling of other complex ions.

Published
2014
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2. DISSOCIATIVE RECOMBINATION MEASUREMENTS OF HCl+ USING AN ION STORAGE RING.

Author

Novotný, O., Becker, A., Buhr, H., Domesle, C., Geppert, W., Grieser, M., Krantz, C., Kreckel, H., Repnow, R., Schwalm, D., Spruck, K., Stützel, J., Yang, B., Wolf, A., and Savin, D. W.

Subjects
ION recombination, STORAGE rings, HEAVY ions, ASTROCHEMISTRY, ASTROPHYSICS research
Abstract

We have measured dissociative recombination (DR) of HCl+ with electrons using a merged beams configuration at the TSR heavy-ion storage ring located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. We present the measured absolute merged beams recombination rate coefficient for collision energies from 0 to 4.5 eV. We have also developed a new method for deriving the cross section from the measurements. Our approach does not suffer from approximations made by previously used methods. The cross section was transformed to a plasma rate coefficient for the electron temperature range from T = 10 to 5000 K. We show that the previously used HCl+ DR data underestimate the plasma rate coefficient by a factor of 1.5 at T = 10 K and overestimate it by a factor of three at T = 300 K. We also find that the new data may partly explain existing discrepancies between observed abundances of chlorine-bearing molecules and their astrochemical models. [ABSTRACT FROM AUTHOR]

Published
2013
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3. Recombination of W18+ ions with electrons: Absolute rate coefficients from a storage-ring experiment and from theoretical calculations.

Author

Spruck, K., Badnell, N. R., Krantz, C., Novotný, O., Becker, A., Bernhardt, D., Grieser, M., Hahn, M., Repnow, R., Savin, D. W., Wolf, A., Müller, A., and Schippers, S.

Subjects
*TUNGSTEN ions, *TRANSITION state theory (Chemistry), *ION recombination, *ELECTRON impact ionization, *ATOMIC structure
Abstract

We present experimentally measured and theoretically calculated rate coefficients for the electron-ion recombination of W18+([Kr]4d104f10) forming W17+. At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping recombination resonances. In the temperature range where the fractional abundance of W18+ is expected to peak in a fusion plasma, the experimentally derived Maxwellian recombination rate coefficient is 5 to 10 times larger than that which is currently recommended for plasma modeling. The complexity of the atomic structure of the open-4f system under study makes the theoretical calculations extremely demanding. Nevertheless, the results of the present Breit-Wigner partitioned dielectronic recombination calculations agree reasonably well with the experimental findings. This also gives confidence in the ability of the theory to generate sufficiently accurate atomic data for the plasma modeling of other complex ions. [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

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