Rudolf Rüffer

Publications (17)3.57 Total impact

• Article: Vibrational properties of the polymeric spin crossover (SCO) Fe(ii) complexes [{Fe(4-amino-1,2,4-triazole)(3)}X(2)](n): a nuclear inelastic scattering (NIS), Raman and DFT study.

  Sergej Rackwitz, Juliusz A Wolny, Kai Muffler, Klaus Achterhold, Rudolf Rüffer, Yann Garcia, Rolf Diller, Volker Schünemann
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  ABSTRACT: The vibrational properties of the cationic spin crossover (SCO) coordination polymers [{Fe(4-amino-1,2,4-triazole)(3)}(+2)](n) containing the anions chlorine, methanosulfonate and 1-naphthalenesulfonate have been studied via nuclear inelastic scattering of synchrotron radiation (NIS) as well as by Raman spectroscopy. Although the different anions have a strong influence on the spin crossover temperature, they have little effect on the positions of the spin marker bands in the NIS and Raman spectra. By comparing the line positions of the NIS spin marker bands with those observed by Raman spectroscopy, it has been possible to distinguish vibrations symmetry (A(u) or A(g)) because modes of A(u) and A(g) symmetries are NIS active, but only the A(g) modes are Raman active. The normal mode analysis of charge compensated cationic pentameric and hexameric model structures which have been obtained by density functional calculations reproduces the experimentally observed mode frequencies and the geometry optimization reproduces iron-ligand distances reported for these and related SCO coordination complexes. The effect of charge compensation appears to be independent of the choice of the functional and the basis set which shows that DFT calculations using B3LYP in conjunction with the basis set CEP-31G are a time effective approach in order to study vibrational properties of Fe(ii) SCO compounds.
  Physical Chemistry Chemical Physics 10/2012; 14(42):14650-60. · 3.57 Impact Factor
• Article: Dynamics of Metal Centers Monitored by Nuclear Inelastic Scattering

  Hauke Paulsen, Patrick Wegner, Heiner Winkler, Juliusz Adam Wolny, Lars H. Böttger, Alfred Xaver Trautwein, Christian Schmidt, Volker Schünemann, Giampaolo Barone, Arturo Silvestri, Gianfranco La Manna, Aleksandr I. Chumakov, I. Sergueev, Rudolf Rüffer
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  ABSTRACT: Nuclear inelastic scattering of synchrotron radiation has been used now since 10 years as a tool for vibrational spectroscopy. This method has turned out especially useful in case of large molecules that contain a M\"ossbauer active metal center. Recent applications to iron-sulfur proteins, to iron(II) spin crossover complexes and to tin-DNA complexes are discussed. Special emphasis is given to the combination of nuclear inelastic scattering and density functional calculations.
  06/2012;
• Article: Nuclear Resonance Vibrational Spectroscopy of Iron Sulfur Proteins

  Alfred Xaver Trautwein, Patrick Wegner, Heiner Winkler, Hauke Paulsen, Volker Schünemann, Christian Schmidt, Aleksandr I Chumakov, Rudolf Rüffer
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  ABSTRACT: Nuclear inelastic scattering in conjunction with density functional theory (DFT) calculations has been applied for the identification of vibrational modes of the high-spin ferric and the high-spin ferrous iron–sulfur center of a rubredoxin-type protein from the thermophylic bacterium Pyrococcus abysii.
  Hyperfine Interact. 06/2012; 165(1-4):295-298.
• Article: Nuclear resonant scattering and molecular orbital calculations on an iron(II) spin-crossover complex

  Hanne Grünsteudel, Hauke Paulsen, Wolfram Meyer-Klaucke, Heiner Winkler, Alfred Xaver Trautwein, H F Grünsteudel, A Q R Baron, Aleksandr I Chumakov, Rudolf Rüffer, Hans Toftlund
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  ABSTRACT: Nuclear resonant scattering of synchrotron radiation was applied to investigate the spin?crossover complex Fe(tpa)(NCS)2 (tpa=tris(2?pyridylmethyl)amine). The nuclear forward scattering experiments are compared with conventional Mössbauer experiments, and the nuclear inelastic scattering experiments are compared with the results from a theoretical normal mode analysis based on molecular orbital calculations.
  Hyperfine Interactions. 113:311-317.
• Source

  Available from: narod.ru

  Article: Nuclear resonant inelastic absorption of synchrotron radiation in an anisotropic single crystal

  VG Kohn, Aleksandr I Chumakov, Rudolf Rüffer
  Physical Review B. 58:8437.
• Source

  Available from: Victor Kohn

  Article: Lattice modes in molecular crystals measured with nuclear inelastic scattering

  V G Kohn, Aleksandr I Chumakov, Rudolf Rüffer
  Physical Review B. 73:094306.
• Chapter: ESRF Highlights 1999

  Aleksandr I Chumakov, Rudolf Rüffer, Olaf Leupold, H Grünsteudel, A Barla, T Asthalter
  pages 50;
• Article: Nuclear inelastic scattering

  Aleksandr I Chumakov, Rudolf Rüffer
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  ABSTRACT: The development of the new field of nuclear inelastic scattering is reviewed. The experimental technique and the variety of applications are illustrated by recent results obtained at the Nuclear Resonance beamline of the European Synchrotron Radiation Facility.
  Hyperfine Interactions. 113(1-4):59-79.
• Article: Nuclear inelastic scattering

  Rudolf Rüffer, Aleksandr I Chumakov
  Hyperfine Interactions. 128:255-272.
• Article: Atom-Selective Vibrational Spectroscopy: Ferrocene Probed via the Iron Atom

  Upali A Jayasooriya, S A Malone, Aleksandr I Chumakov, Rudolf Rüffer, A R Overweg, C R Nicklin
  CHEMPHYSCHEM. 3:177-180.
• Article: Mode Selective Studies of Lattice Dynamics in Macromolecules

  Aleksandr I Chumakov, Rudolf Rüffer, Olaf Leupold, H Grünsteudel, A Barla, Tanja Asthalter
  ESRF Highlights 1999.
• Article: Anisotropic inelastic nuclear absorption

  Aleksandr I Chumakov, Rudolf Rüffer, AQR Baron, Hanne Grünsteudel, HF Grünsteudel, VG Kohn
  Physical Review B. 56(17):10758-10761.
• Article: High-energy-resolution x-ray optics with refractive collimators

  Aleksandr I Chumakov, Rudolf Rüffer, Olaf Leupold, A Barla, H Thiess, Tanja Asthalter, BP Doyle, A Snigrirev, AQR Baron
  ESRF.
• Article: Energy dependence of nuclear recoil measured with incoherent nuclear scattering of synchrotron radiation

  Aleksandr I Chumakov, Rudolf Rüffer, Hanne Grünsteudel, HF Grünsteudel, G Grübel, J Metge, Olaf Leupold, HA Goodwin
  Europhysics Letters. 30(7):427-432.
• Article: Nuclear Resonance Beamline at ESRF

  Rudolf Rüffer, Aleksandr I Chumakov
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  ABSTRACT: The Nuclear Resonance Beamline at ESRF is dedicated to the excitation of nuclear levels by synchrotron radiation. The sources of radiation and optical elements are optimized to provide an intense, highly monochromatic, collimated and stable X-ray beam of small cross-section at the Mössbauer transition energies between 6 and 30 keV. The set-up of the beamline allows to perform studies in diffraction, small angle scattering, forward scattering and incoherent scattering. Equipment is available to maintain the sample at variable temperature and magnetic field. Fast detectors and timing electronics serve to separate the delayed nuclear scattering from the ldquopromptrdquo electronic scattering and to measure the time spectra of nuclear radiation with sub-nanosecond resolution. The general lay-out and the parameters of the beamline are reported. Typical domains of applications are discussed and illustrated by first experimental results.
  Hyperfine Interact. 97-98:589-604.
• Article: Spin- and phase transition in the spin crossover complex [Fe(ptz)6](BF4)2 studied by nuclear inelastic scattering of synchrotron radiation and by DFT calculations

  Lars H Böttger, Aleksandr I Chumakov, Matthias Grunert, Philipp Gütlich, Joachim Kusz, Hauke Paulsen, Ulrich Ponkratz, Rudolf Rüffer, Ventzislav Rusanov, Alfred Xaver Trautwein, Juliusz Adam Wolny
  [show abstract] [hide abstract]
  ABSTRACT: Nuclear inelastic scattering (NIS) spectra of [Fe(ptz)6](BF4)2 (ptz = 1-n-propyl-tetrazole) have been measured for five phases differing in spin state and crystallographic structure. Different spectral patterns have been found for the low-spin and high-spin phases and are described in terms of normal coordinate analysis of the complex molecule. For both low-spin and high-spin phases the conversion from ordered to disordered phase results in splitting of the observed NIS bands. Packing becomes visible in the NIS spectra via coupling of the Fe–N stretching vibrations with those of the terminal n-propyl groups. The DFT-based normal coordinate analysis also reveals the character of Raman markers.
  Chemical Physics Letters. 429:189-193.
• Article: Temperature dependent inelastic X-ray scattering of synchrotron radiation on myoglobin analyzed by the Mössbauer effect

  Klaus Achterhold, C Keppler, Uwe Bürck, W Potzel, P Schindelmann, Ernst-Walter Knapp, B Melchers, Aleksandr I Chumakov, A Q R Baron, Rudolf Rüffer, F Parak
  Biophysics Letter. 25:43-46.