TY - JOUR A1 - Könnecke, Rene A1 - Follath, R. A1 - Pontius, N. A1 - Schlappa, J. A1 - Eggenstein, F. A1 - Zeschke, T. A1 - Bischoff, P. A1 - Schmidt, J. -S. A1 - Noll, T. A1 - Trabant, C. A1 - Schreck, S. A1 - Wernet, Ph. A1 - Eisebitt, S. A1 - Senf, F. A1 - Schuessler-Langeheine, Christian A1 - Erko, A. A1 - Föhlisch, Alexander T1 - The confocal plane grating spectrometer at BESSY II JF - Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy N2 - At BESSY II a confocal plane grating spectrometer for resonant inelastic X-ray scattering (RIXS) is currently under commissioning. The new endstation operates with a source size of 4 x 1 mu m(2) provided by its dedicated beamline. The RIXS-spectrometer covers an energy range from 50 eV to 1000 eV, providing a resolving power E/Delta E of 5000-15,000. The beamline allows full polarization control and gives a photon flux of up to 7 x 10(14) photons/s/0.1 A/0.1%bandwidth by offering a resolving power E/Delta E of 4000-12,000. KW - Resonant inelastic X-ray scattering KW - Soft X-ray monochromator KW - High transmission micro focus beamline KW - Plane grating emission spectrometer Y1 - 2013 U6 - https://doi.org/10.1016/j.elspec.2012.11.003 SN - 0368-2048 VL - 188 SP - 133 EP - 139 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Kunnus, Kristjan A1 - Josefsson, I. A1 - Schreck, Simon Frederik A1 - Quevedo, W. A1 - Miedema, P. S. A1 - Techert, S. A1 - de Groot, F. M. F. A1 - Föhlisch, Alexander A1 - Odelius, M. A1 - Wernet, Ph. T1 - Quantifying covalent interactions with resonant inelastic soft X-ray scattering BT - case study of Ni2+ aqua complex JF - Chemical physics letters N2 - We analyze the effects of covalent interactions in Ni 2p3d resonant inelastic X-ray scattering (RIXS) spectra from aqueous Ni2+ ions and find that the relative RIXS intensities of ligand-to-metal charge-transfer final states with respect to the ligand-field final states reflect the covalent mixing between Ni 3d and water orbitals. Specifically, the experimental intensity ratio at the Ni L-3-edge allows to determine that the Ni 3d orbitals have on average 5.5% of water character. We propose that 2p3d RIXS at the Ni L-3-edge can be utilized to quantify covalency in Ni complexes without the use of external references or simulations. KW - Transition-metal ion KW - Aqueous solution KW - Covalent interaction KW - Resonant inelastic X-ray scattering KW - Ligand-field state KW - Charge-transfer state Y1 - 2016 U6 - https://doi.org/10.1016/j.cplett.2016.12.046 SN - 0009-2614 SN - 1873-4448 VL - 669 SP - 196 EP - 201 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Beye, Martin A1 - Wernet, Ph. A1 - Schüßler-Langeheine, Christian A1 - Föhlisch, Alexander T1 - Time resolved resonant inelastic X-ray scattering: a supreme tool to understand dynamics in solids and molecules JF - Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy N2 - Dynamics in materials typically involve different degrees of freedom, like charge, lattice, orbital and spin in a complex interplay. Time-resolved resonant inelastic X-ray scattering (RIXS) as a highly selective tool can provide unique insight and follow the details of dynamical processes while resolving symmetries, chemical and charge states, momenta, spin configurations, etc. In this paper, we review examples where the intrinsic scattering duration time is used to study femtosecond phenomena. Free-electron lasers access timescales starting in the sub-ps range through pump-probe methods and synchrotrons study the time scales longer than tens of ps. In these examples, time-resolved resonant inelastic X-ray scattering is applied to solids as well as molecular systems. KW - Resonant inelastic X-ray scattering KW - Ultrafast spectroscopy KW - Phase transitions KW - Molecular dynamics Y1 - 2013 U6 - https://doi.org/10.1016/j.elspec.2013.04.013 SN - 0368-2048 VL - 188 IS - 3 SP - 172 EP - 182 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Beye, Martin A1 - Föhlisch, Alexander T1 - Soft X-ray probes of ultrafast dynamics for heterogeneous catalysis JF - Chemical physics : a journal devoted to experimental and theoretical research involving problems of both a chemical and physical nature N2 - Soft X-ray spectroscopy is one of the best tools to directly address the electronic structure, the driving force of chemical reactions. It enables selective studies on sample surfaces to single out reaction centers in heterogeneous catalytic reactions. With core-hole clock methods, specific dynamics are related to the femtosecond life time of a core-hole. Typically, this method is used with photoemission spectroscopy, but advancements in soft X-ray emission techniques render more specific studies possible. With the advent of bright femtosecond pulsed soft X-ray sources, highly selective pump-probe X-ray emission studies are enabled with temporal resolutions down to tens of femtoseconds. This finally allows to study dynamics in the electronic structure of adsorbed reaction centers on the whole range of relevant time scales - closing the gap between kinetic soft X-ray studies and the atto- to femtosecond core-hole clock techniques. KW - Core-hole clock KW - Resonant inelastic X-ray scattering KW - Ultrafast surface science KW - Photoelectron spectroscopy Y1 - 2013 U6 - https://doi.org/10.1016/j.chemphys.2012.03.023 SN - 0301-0104 SN - 1873-4421 VL - 414 IS - 5 SP - 130 EP - 138 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Beye, Martin A1 - Föhlisch, Alexander T1 - A soft X-ray approach to electron-phonon interactions beyond the Born-Oppenheimer approximation JF - Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy N2 - With modern soft X-ray methods, the whole field of electron-phonon interactions becomes accessible directly in the ultrafast time domain with ultrashort pulsed X-ray sources, as well as in the energy domain through modern highly resolving spectrometers. The well-known core-hole clock approach plays an intermediate role, resolving energetic and temporal features at the same time. In this perspective paper, we review several experiments to illustrate the modern advances in the selective study of electron-phonon interactions as fundamentally determining ingredients for materials properties. We present the different complementary approaches that can be taken with soft X-ray methods to conquer this field beyond the Born-Oppenheimer approximation. KW - Electron-phonon coupling KW - Resonant inelastic X-ray scattering KW - X-ray emission spectroscopy KW - Near edge X-ray absorption fine structure Y1 - 2011 U6 - https://doi.org/10.1016/j.elspec.2010.12.032 SN - 0368-2048 VL - 184 IS - 3-6 SP - 313 EP - 317 PB - Elsevier CY - Amsterdam ER -