Conference paper

Publication year: 2007

Journal: Journal of Physics: Conference Series

Volume number: 58

DOI Link: https://doi.org/10.1088/1742-6596/58/1/047

Conference: 13th International Conference on the Physics of Highly Charged Ions (HCI)

Publisher: IOP Publishing: Conference Series

Abstract: 

Recent spectroscopic models of active galactic nuclei have indicated that the recommended electron-ion recombination rate coeficients for iron ions with partially filled Mshells are incorrect in the temperature range where these ions form in photoionized plasmas. We have investigated this experimentally for Fe⁷⁺ forming Fe⁶⁺, Fe⁸⁺ forming Fe⁷⁺, and Fe¹³⁺ forming Fe¹²⁺. The recombination rate coeficient was measured employing the electron-ion merged beams method at the Heidelberg heavy-ion storage-ring TSR. The measured energy range encompassed at least all dielectronic recombination (DR) resonances associated with core excitations within the M-shell of the parent ions. Already in our first measurement, that is for Fe¹³⁺, we find unusually strong DR resonances at low electron-ion collision energies leading to low temperature plasma DR rate coeficients orders of magnitude larger than the recommended rate coeficient.

Harvard Citation style: Schmidt, E., Schippers, S., Brandau, C., Bernhardt, D., Müller, A., Lestinsky, M., et al. (2007) Electron-ion recombination measurements of Fe7+, Fe8+, Fe13+ motivated by active galactic nuclei x-ray absorption features, Journal of Physics: Conference Series, 58, Article 223. https://doi.org/10.1088/1742-6596/58/1/047

APA Citation style: Schmidt, E., Schippers, S., Brandau, C., Bernhardt, D., Müller, A., Lestinsky, M., Sprenger, F., Homann, J., Orlov, D., Grieser, M., Repnow, R., Wolf, A., Lukić, D., Schnell, M., & Savin, D. (2007). Electron-ion recombination measurements of Fe7+, Fe8+, Fe13+ motivated by active galactic nuclei x-ray absorption features. Journal of Physics: Conference Series. 58, Article 223. https://doi.org/10.1088/1742-6596/58/1/047