TY  - JOUR
A1  - Beye, Martin
A1  - Öberg, Henrik
A1  - Xin, Hongliang
A1  - Dakovski, Georgi L.
A1  - Föhlisch, Alexander
A1  - Gladh, Jorgen
A1  - Hantschmann, Markus
A1  - Hieke, Florian
A1  - Kaya, Sarp
A1  - Kühn, Danilo
A1  - LaRue, Jerry
A1  - Mercurio, Giuseppe
A1  - Minitti, Michael P.
A1  - Mitra, Ankush
A1  - Moeller, Stefan P.
A1  - Ng, May Ling
A1  - Nilsson, Anders
A1  - Nordlund, Dennis
A1  - Norskov, Jens
A1  - Öström, Henrik
A1  - Ogasawara, Hirohito
A1  - Persson, Mats
A1  - Schlotter, William F.
A1  - Sellberg, Jonas A.
A1  - Wolf, Martin
A1  - Abild-Pedersen, Frank
A1  - Pettersson, Lars G. M.
A1  - Wurth, Wilfried
T1  - Chemical Bond Activation Observed with an X-ray Laser
JF  - The journal of physical chemistry letters
N2  - The concept of bonding and antibonding orbitals is fundamental in chemistry. The population of those orbitals and the energetic difference between the two reflect the strength of the bonding interaction. Weakening the bond is expected to reduce this energetic splitting, but the transient character of bond-activation has so far prohibited direct experimental access. Here we apply time-resolved soft X-ray spectroscopy at a free electron laser to directly observe the decreased bonding antibonding splitting following bond-activation using an ultrashort optical laser pulse.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.jpclett.6b01543
SN  - 1948-7185
VL  - 7
SP  - 3647
EP  - 3651
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Kühn, Danilo
A1  - Giangrisostomi, Erika
A1  - Jay, Raphael Martin
A1  - Sorgenfrei, Florian
A1  - Föhlisch, Alexander
T1  - The influence of x-ray pulse length on space-charge effects in optical pump/x-ray probe photoemission
JF  - New journal of physics : the open-access journal for physics
N2  - Pump-probe photoelectron spectroscopy (PES) is a versatile tool to investigate the dynamics of transient states of excited matter. Vacuum space-charge effects can mask these dynamics and complicate the interpretation of electron spectra. Here we report on space-charge effects in Au 4f photoemission from a polycrystalline gold surface, excited with moderately intense 90 ps (FWHM) soft x-ray probe pulses, under the influence of the Coulomb forces exerted by a pump electron cloud, which was produced by intense 40 fs laser pulses. The experimentally observed kinetic energy shift and spectral broadening of the Au 4f lines, measured with highly-efficient time-of-flight spectroscopy, are in good agreement with simulations utilizing a mean-field model of the electrostatic pump electron potential. This confirms that the line broadening is predominantly caused by variations in the take-off time of the probe electrons without appreciable influence of local scattering events. Our findings might be of general interest for pump-probe PES with picosecond-pulse-length sources.
KW  - space-charge effects
KW  - mean-field model
KW  - x-ray photoemission
KW  - electron spectroscopy
KW  - pump-probe
KW  - ARTOF
Y1  - 2019
U6  - https://doi.org/10.1088/1367-2630/ab2f5c
SN  - 1367-2630
VL  - 21
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  - 
TY  - JOUR
A1  - Kühn, Danilo
A1  - Müller, Moritz
A1  - Sorgenfrei, Florian
A1  - Giangrisostomi, Erika
A1  - Jay, Raphael Martin
A1  - Ovsyannikov, Ruslan
A1  - Martensson, Nils
A1  - Sanchez-Portal, Daniel
A1  - Föhlisch, Alexander
T1  - Directional sub-femtosecond charge transfer dynamics and the dimensionality of 1T-TaS2
JF  - Scientific reports
N2  - For the layered transition metal dichalcogenide 1T-TaS2, we establish through a unique experimental approach and density functional theory, how ultrafast charge transfer in 1T-TaS2 takes on isotropic three-dimensional character or anisotropic two-dimensional character, depending on the commensurability of the charge density wave phases of 1T-TaS2. The X-ray spectroscopic core-hole-clock method prepares selectively in-and out-of-plane polarized sulfur 3p orbital occupation with respect to the 1T-TaS2 planes and monitors sub-femtosecond wave packet delocalization. Despite being a prototypical two-dimensional material, isotropic three-dimensional charge transfer is found in the commensurate charge density wave phase (CCDW), indicating strong coupling between layers. In contrast, anisotropic two-dimensional charge transfer occurs for the nearly commensurate phase (NCDW). In direct comparison, theory shows that interlayer interaction in the CCDW phase - not layer stacking variations - causes isotropic three-dimensional charge transfer. This is presumably a general mechanism for phase transitions and tailored properties of dichalcogenides with charge density waves.
Y1  - 2019
U6  - https://doi.org/10.1038/s41598-018-36637-0
SN  - 2045-2322
VL  - 9
IS  - 488
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Kühn, Danilo
A1  - Sorgenfrei, Florian
A1  - Giangrisostomi, Erika
A1  - Jay, Raphael
A1  - Musazay, Abdurrahman
A1  - Ovsyannikov, Ruslan
A1  - Strahlman, Christian
A1  - Svensson, Svante
A1  - Mårtensson, Nils
A1  - Föhlisch, Alexander
T1  - Capabilities of angle resolved time of flight electron spectroscopy with the 60 degrees wide angle acceptance lens
JF  - Journal of electron spectroscopy and related phenomena : the international journal on theoretical and experimental aspects of electron spectroscopy
N2  - The simultaneous detection of energy, momentum and temporal information in electron spectroscopy is the key aspect to enhance the detection efficiency in order to broaden the range of scientific applications. Employing a novel 60 degrees wide angle acceptance lens system, based on an additional accelerating electron optical element, leads to a significant enhancement in transmission over the previously employed 30 degrees electron lenses. Due to the performance gain, optimized capabilities for time resolved electron spectroscopy and other high transmission applications with pulsed ionizing radiation have been obtained. The energy resolution and transmission have been determined experimentally utilizing BESSY II as a photon source. Four different and complementary lens modes have been characterized. (C) 2017 The Authors. Published by Elsevier B.V.
KW  - Artof
KW  - Electron spectroscopy
KW  - Wide angle
KW  - Time of flight
KW  - Energy resolution
KW  - Synchrotron
Y1  - 2018
U6  - https://doi.org/10.1016/j.elspec.2017.06.008
SN  - 0368-2048
SN  - 1873-2526
VL  - 224
SP  - 45
EP  - 50
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kühn, Florian P.
T1  - Mehr Politik!
JF  - WeltTrends-Papiere
N2  - Inhalt: - Welche Staatlichkeit? - Gewalt folgt einer eigenen Logik - Beispiel Afghanistan - Mehr Sicherheit? Für wen? - Risiko ist keine Bedrohung - Nassauer hat Recht und zugleich Unrecht
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-31761
SN  - 1864-0656
IS  - 5
SP  - 41
EP  - 46
ER  - 
TY  - JOUR
A1  - Rusche, Tim Maxian
A1  - Bielawski, Martina
A1  - Riemann, Silke
A1  - Reimers, Lutz
A1  - Duplouy, Florent
A1  - Kuhn, Florian
A1  - von Oettingen, Anna
T1  - Deutsche Interessen offen diskutieren!
BT  - Plädoyer für eine neue außenpolitische Kultur
JF  - WeltTrends-Papiere
N2  - Inhalt: 1. Werte und Selbstverständnis behutsam erneuern Globalisierung Demografischer Wandel Klimawandel 2. Langfristig ökonomischen Wohlstand sichern Bildung Forschung und Entwicklung Außenwirtschaft 3. Plädoyer für eine neue außenpolitische Kultur : Deutsche Interessen – Ein Anachronismus? Status quo: Interessendefinition im Hinterzimmer Interessen klar definieren und erfolgreich durchsetzen Entscheidungsmatrix für Auslandseinsätze Evaluierung des Nutzens Evaluierung der Kosten Ableiten der Entscheidung Und die Moral? – Aber sicher! Der Tönissteiner Kreis
KW  - Außenpolitik
KW  - Interessen
KW  - Deutschland
KW  - foreign Policy
KW  - national interests
KW  - Germany
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-62734
SN  - 1864-0656
IS  - 20
SP  - 9
EP  - 17
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Rusche, Tim Maxian
A1  - Duplouy, Florent
A1  - Kuhn, Florian
A1  - von Oettingen, Anna
T1  - Deutsche Interessen
BT  - Young Tönissteiner antworten ihren Kritikern
JF  - WeltTrends-Papiere
N2  - Inhalt: Interessen, Werte und Normen bedingen sich wechselseitig! Werte und Normen lassen sich als Interessen definieren! Debattenkultur gegen das Informationsdefizit! Was ist deutsch an deutschen Interessen?
KW  - Außenpolitik
KW  - Interessen
KW  - Deutschland
KW  - foreign Policy
KW  - national interests
KW  - Germany
Y1  - 2011
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-62837
SN  - 1864-0656
IS  - 20
SP  - 56
EP  - 59
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - JOUR
A1  - Schäfer, Marjänn Helena
A1  - Kakularam, Kumar Reddy
A1  - Reisch, Florian
A1  - Rothe, Michael
A1  - Stehling, Sabine
A1  - Heydeck, Dagmar
A1  - Püschel, Gerhard Paul
A1  - Kuhn, Hartmut
T1  - Male Knock-in Mice Expressing an Arachidonic Acid Lipoxygenase 15B (Alox15B) with Humanized Reaction Specificity Are Prematurely Growth Arrested When Aging
JF  - Biomedicines
N2  - Mammalian arachidonic acid lipoxygenases (ALOXs) have been implicated in cell differentiation and in the pathogenesis of inflammation. The mouse genome involves seven functional Alox genes and the encoded enzymes share a high degree of amino acid conservation with their human orthologs. There are, however, functional differences between mouse and human ALOX orthologs. Human ALOX15B oxygenates arachidonic acid exclusively to its 15-hydroperoxy derivative (15S-HpETE), whereas 8S-HpETE is dominantly formed by mouse Alox15b. The structural basis for this functional difference has been explored and in vitro mutagenesis humanized the reaction specificity of the mouse enzyme. To explore whether this mutagenesis strategy may also humanize the reaction specificity of mouse Alox15b in vivo, we created Alox15b knock-in mice expressing the arachidonic acid 15-lipoxygenating Tyr603Asp+His604Val double mutant instead of the 8-lipoxygenating wildtype enzyme. These mice are fertile, display slightly modified plasma oxylipidomes and develop normally up to an age of 24 weeks. At later developmental stages, male Alox15b-KI mice gain significantly less body weight than outbred wildtype controls, but this effect was not observed for female individuals. To explore the possible reasons for the observed gender-specific growth arrest, we determined the basic hematological parameters and found that aged male Alox15b-KI mice exhibited significantly attenuated red blood cell parameters (erythrocyte counts, hematocrit, hemoglobin). Here again, these differences were not observed in female individuals. These data suggest that humanization of the reaction specificity of mouse Alox15b impairs the functionality of the hematopoietic system in males, which is paralleled by a premature growth arrest.
KW  - eicosanoids
KW  - lipid peroxidation
KW  - oxidative stress
KW  - polyenoic fatty acids
KW  - erythropoiesis
Y1  - 2022
U6  - https://doi.org/10.3390/biomedicines10061379
SN  - 2227-9059
VL  - 10
SP  - 1
EP  - 22
PB  - MDPI
CY  - Basel, Schweiz
ET  - 6
ER  - 
TY  - JOUR
A1  - Stede, Manfred
A1  - Kuhn, Florian
T1  - Identifying the content zones of German court decisions
Y1  - 2009
SN  - 978-3-642- 03423-7
ER  -