Publications (10)16.61 Total impact
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Article: Laser spectroscopy on forbidden transitions in trapped highly charged Ar(13+) ions.
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ABSTRACT: We demonstrate resonant fluorescence laser spectroscopy in highly charged ions (HCI) stored in an electron beam ion trap by investigating the dipole-forbidden 1s(2)2s(2)2p (2)P(3/2)-(2)P(1/2) transition in boronlike Ar(13+) ions. Forced evaporative cooling yielded a high resolving power, resulting in an accurate wavelength determination to λ=441.255 68(26) nm. By applying stronger cooling and two-photon excitation, new optical frequency standards based upon ultrastable transitions in such HCI could be realized in the future, e.g., for the search of time variations of the fine-structure constant.Physical Review Letters 09/2011; 107(14):143002. · 7.37 Impact Factor -
Article: Laser spectroscopy on forbidden transitions in trapped highly charged Ar13+ ions
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ABSTRACT: Export Date: 23 October 2011, Source: Scopus, Art. No.: 143002, CODEN: PRLTA, doi: 10.1103/PhysRevLett.107.143002Physical Review Letters. 01/2011; 107. -
Article: Laser Spectroscopy on Forbidden Transitions in Trapped Highly Charged Ar 13þ Ions
Phys Rev Lett. 01/2011; -
Article: Resonant and near-threshold photoionization cross sections of Fe14+.
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ABSTRACT: Photoionization (PI) of Fe14+ in the range from 450 to 1100 eV was measured at the BESSY II storage ring using an electron beam ion trap achieving high target-ion area densities of 10(10) cm(-2). Photoabsorption by this ion is observed in astrophysical spectra and plasmas, but until now cross sections and resonance energies could only be provided by calculations. We reach a resolving power E/ΔE of at least 6500, outstanding in the present energy range, which enables benchmarking and improving the most advanced theories for PI of ions in high charge states.Physical Review Letters 10/2010; 105(18):183001. · 7.37 Impact Factor -
Article: Photoionization of N3 + and Ar8 + in an electron beam ion trap by synchrotron radiation
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ABSTRACT: Photoionization (PI) of multiply and highly charged ions was studied using an electron beam ion trap and synchrotron radiation at the BESSY II electron storage ring. The versatile new method introduced here extends the range of ions accessible for PI investigations beyond current limitations by providing a dense target of ions in arbitrary, i.e. both low and high charge states. Data on near-threshold PI of N3 + and Ar8 + ions, species of astrophysical and fundamental interest, show high resolution and accuracy allowing various theoretical models to be distinguished, and highlight shortcomings of available PI calculations. We compare our experimental data with our new fully relativistic PI calculations within a multiconfiguration Dirac–Fock approach and with other advanced calculations and find generally good agreement; however, detailed examination reveals significant deviations, especially at the threshold region of Ar8 +.Journal of Physics B Atomic Molecular and Optical Physics 03/2010; 43(6):065003. · 1.88 Impact Factor -
Article: Resonant and near-threshold photoionization cross sections of Fe14 +
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ABSTRACT: Cited By (since 1996): 1, Export Date: 23 October 2011, Source: Scopus, Art. No.: 183001, CODEN: PRLTA, doi: 10.1103/PhysRevLett.105.183001Physical Review Letters. 01/2010; 105. -
Article: Photoionization of ions in arbitrary charge states by synchrotron radiation in an electron beam ion trap
Journal of Physics Conference Series, v.194 (2009). -
Article: Resonant and Near-Threshold Photoionization Cross Sections of Fe(14+)
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ABSTRACT: Photoionization (PI) of Fe(14+) in the range from 450 to 1100 eV was measured at the BESSY II storage ring using an electron beam ion trap achieving high target-ion area densities of 10(10) cm(-2). Photoabsorption by this ion is observed in astrophysical spectra and plasmas, but until now cross sections and resonance energies could only be provided by calculations. We reach a resolving power E/Delta E of at least 6500, outstanding in the present energy range, which enables benchmarking and improving the most advanced theories for PI of ions in high charge states.PHYSICAL REVIEW LETTERS. 105(18). -
Article: Resonant and Near-Threshold Photoionization Cross Sections of Fe14+
Physical Review Letters, v.105 (2010). -
Article: Photoionization of ions in arbitrary charge states by synchrotron radiation in an electron beam ion trap
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ABSTRACT: Photoionization of ions in various charge states is studied with an electron beam iontrap at the synchrotron BESSY II. The ion target density achieved by this method, representing an increase of up to four orders of magnitude with respectto conventional techniques, givesunprecedented access to photoionization of highly charged ions at photon energies reachingthe keV range. Data on near-threshold photoionization of N3+, Ar12+, Fe12+ combined with measurements on neutral gas targets in the same setup demonstrate the versatility of this technique and show both very good resolution and accuracy.Journal of Physics: Conference Series, v.194, 1-6 (2009).
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Institutions
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2010–2011
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Max-Planck-Institut für Kernphysik
Heidelberg, Baden-Wuerttemberg, Germany
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