@article{KubinGuoKrolletal.2018, author = {Kubin, Markus and Guo, Meiyuan and Kroll, Thomas and Loechel, Heike and Kallman, Erik and Baker, Michael L. and Mitzner, Rolf and Gul, Sheraz and Kern, Jan and F{\"o}hlisch, Alexander and Erko, Alexei and Bergmann, Uwe and Yachandra, Vittal and Yano, Junko and Lundberg, Marcus and Wernet, Philippe}, title = {Probing the oxidation state of transition metal complexes}, series = {Chemical science}, volume = {9}, journal = {Chemical science}, number = {33}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {2041-6520}, doi = {10.1039/c8sc00550h}, pages = {6813 -- 6829}, year = {2018}, abstract = {Transition metals in inorganic systems and metalloproteins can occur in different oxidation states, which makes them ideal redox-active catalysts. To gain a mechanistic understanding of the catalytic reactions, knowledge of the oxidation state of the active metals, ideally in operando, is therefore critical. L-edge X-ray absorption spectroscopy (XAS) is a powerful technique that is frequently used to infer the oxidation state via a distinct blue shift of L-edge absorption energies with increasing oxidation state. A unified description accounting for quantum-chemical notions whereupon oxidation does not occur locally on the metal but on the whole molecule and the basic understanding that L-edge XAS probes the electronic structure locally at the metal has been missing to date. Here we quantify how charge and spin densities change at the metal and throughout the molecule for both redox and core-excitation processes. We explain the origin of the L-edge XAS shift between the high-spin complexes Mn-II(acac)(2) and Mn-III(acac)(3) as representative model systems and use ab initio theory to uncouple effects of oxidation-state changes from geometric effects. The shift reflects an increased electron affinity of Mn-III in the core-excited states compared to the ground state due to a contraction of the Mn 3d shell upon core-excitation with accompanied changes in the classical Coulomb interactions. This new picture quantifies how the metal-centered core hole probes changes in formal oxidation state and encloses and substantiates earlier explanations. The approach is broadly applicable to mechanistic studies of redox-catalytic reactions in molecular systems where charge and spin localization/delocalization determine reaction pathways.}, language = {en} } @misc{KubinGuoKrolletal.2018, author = {Kubin, Markus and Guo, Meiyuan and Kroll, Thomas and L{\"o}chel, Heike and K{\"a}llman, Erik and Baker, Michael L. and Mitzner, Rolf and Gul, Sheraz and Kern, Jan and F{\"o}hlisch, Alexander and Erko, Alexei and Bergmann, Uwe and Yachandra, Vittal and Yano, Junko and Lundberg, Marcus and Wernet, Philippe}, title = {Probing the oxidation state of transition metal complexes}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {656}, issn = {1866-8372}, doi = {10.25932/publishup-42505}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425057}, pages = {17}, year = {2018}, abstract = {Transition metals in inorganic systems and metalloproteins can occur in different oxidation states, which makes them ideal redox-active catalysts. To gain a mechanistic understanding of the catalytic reactions, knowledge of the oxidation state of the active metals, ideally in operando, is therefore critical. L-edge X-ray absorption spectroscopy (XAS) is a powerful technique that is frequently used to infer the oxidation state via a distinct blue shift of L-edge absorption energies with increasing oxidation state. A unified description accounting for quantum-chemical notions whereupon oxidation does not occur locally on the metal but on the whole molecule and the basic understanding that L-edge XAS probes the electronic structure locally at the metal has been missing to date. Here we quantify how charge and spin densities change at the metal and throughout the molecule for both redox and core-excitation processes. We explain the origin of the L-edge XAS shift between the high-spin complexes Mn-II(acac)(2) and Mn-III(acac)(3) as representative model systems and use ab initio theory to uncouple effects of oxidation-state changes from geometric effects. The shift reflects an increased electron affinity of Mn-III in the core-excited states compared to the ground state due to a contraction of the Mn 3d shell upon core-excitation with accompanied changes in the classical Coulomb interactions. This new picture quantifies how the metal-centered core hole probes changes in formal oxidation state and encloses and substantiates earlier explanations. The approach is broadly applicable to mechanistic studies of redox-catalytic reactions in molecular systems where charge and spin localization/delocalization determine reaction pathways.}, language = {en} } @article{KubinKernGuletal.2017, author = {Kubin, Markus and Kern, Jan and Gul, Sheraz and Kroll, Thomas and Chatterjee, Ruchira and Loechel, Heike and Fuller, Franklin D. and Sierra, Raymond G. and Quevedo, Wilson and Weniger, Christian and Rehanek, Jens and Firsov, Anatoly and Laksmono, Hartawan and Weninger, Clemens and Alonso-Mori, Roberto and Nordlund, Dennis L. and Lassalle-Kaiser, Benedikt and Glownia, James M. and Krzywinski, Jacek and Moeller, Stefan and Turner, Joshua J. and Minitti, Michael P. and Dakovski, Georgi L. and Koroidov, Sergey and Kawde, Anurag and Kanady, Jacob S. and Tsui, Emily Y. and Suseno, Sandy and Han, Zhiji and Hill, Ethan and Taguchi, Taketo and Borovik, Andrew S. and Agapie, Theodor and Messinger, Johannes and Erko, Alexei and F{\"o}hlisch, Alexander and Bergmann, Uwe and Mitzner, Rolf and Yachandra, Vittal K. and Yano, Junko and Wernet, Philippe}, title = {Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers}, series = {Structural dynamics}, volume = {4}, journal = {Structural dynamics}, publisher = {American Institute of Physics}, address = {Melville}, issn = {2329-7778}, doi = {10.1063/1.4986627}, pages = {16}, year = {2017}, abstract = {X-ray absorption spectroscopy at the L-edge of 3d transition metals provides unique information on the local metal charge and spin states by directly probing 3d-derived molecular orbitals through 2p-3d transitions. However, this soft x-ray technique has been rarely used at synchrotron facilities for mechanistic studies of metalloenzymes due to the difficulties of x-ray-induced sample damage and strong background signals from light elements that can dominate the low metal signal. Here, we combine femtosecond soft x-ray pulses from a free-electron laser with a novel x-ray fluorescence-yield spectrometer to overcome these difficulties. We present L-edge absorption spectra of inorganic high-valent Mn complexes (Mn similar to 6-15 mmol/l) with no visible effects of radiation damage. We also present the first L-edge absorption spectra of the oxygen evolving complex (Mn4CaO5) in Photosystem II (Mn < 1 mmol/l) at room temperature, measured under similar conditions. Our approach opens new ways to study metalloenzymes under functional conditions. (C) 2017 Author(s).}, language = {en} } @article{VogelKroll2016, author = {Vogel, Dominik and Kroll, Alexander}, title = {The stability and change of psm-related values across time}, series = {International public management journal}, volume = {19}, journal = {International public management journal}, publisher = {J. C. B. Mohr}, address = {Abingdon}, issn = {1096-7494}, doi = {10.1080/10967494.2015.1047544}, pages = {53 -- 77}, year = {2016}, abstract = {This article is a response to calls in prior research that we need more longitudinal analyses to better understand the foundations of PSM and related prosocial values. There is wide agreement that it is crucial for theory building but also for tailoring hiring practices and human resource development programs to sort out whether PSM-related values are stable or developable. The article summarizes existent theoretical expectations, which turn out to be partially conflicting, and tests them against multiple waves of data from the German Socio-Economic Panel Study which covers a time period of 16 years. It finds that PSM-related values of public employees are stable rather than dynamic but tend to increase with age and decrease with organizational membership. The article also examines cohort effects, which have been neglected in prior work, and finds moderate evidence that there are differences between those born during the Second World War and later generations.}, language = {en} } @misc{VogelKroll2016, author = {Vogel, Dominik and Kroll, Alexander}, title = {The Stability and Change of PSM-related Values across Time}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-397783}, pages = {29}, year = {2016}, abstract = {This article is a response to calls in prior research that we need more longitudi-nal analyses to better understand the foundations of PSM and related prosocial values. There is wide agreement that it is crucial for theory-building but also for tailoring hiring practices and human resource development programs to sort out whether PSM-related values are stable or developable. The article summarizes existent theoretical expecta-tions, which turn out to be partially conflicting, and tests them against multiple waves of data from the German Socio-Economic Panel Study which covers a time period of sixteen years. It finds that PSM-related values of public employees are stable rather than dynamic but tend to increase with age and decrease with organizational member-ship. The article also examines cohort effects, which have been neglected in prior work, and finds moderate evidence that there are differences between those born during the Second World War and later generations.}, language = {en} } @article{KrollKernKubinetal.2016, author = {Kroll, Thomas and Kern, Jan and Kubin, Markus and Ratner, Daniel and Gul, Sheraz and Fuller, Franklin D. and L{\"o}chel, Heike and Krzywinski, Jacek and Lutman, Alberto and Ding, Yuantao and Dakovski, Georgi L. and Moeller, Stefan and Turner, Joshua J. and Alonso-Mori, Roberto and Nordlund, Dennis L. and Rehanek, Jens and Weniger, Christian and Firsov, Alexander and Brzhezinskaya, Maria and Chatterjee, Ruchira and Lassalle-Kaiser, Benedikt and Sierra, Raymond G. and Laksmono, Hartawan and Hill, Ethan and Borovik, Andrew S. and Erko, Alexei and F{\"o}hlisch, Alexander and Mitzner, Rolf and Yachandra, Vittal K. and Yano, Junko and Wernet, Philippe and Bergmann, Uwe}, title = {X-ray absorption spectroscopy using a self-seeded soft X-ray free-electron laser}, series = {Optics express : the international electronic journal of optics}, volume = {24}, journal = {Optics express : the international electronic journal of optics}, publisher = {Optical Society of America}, address = {Washington}, issn = {1094-4087}, doi = {10.1364/OE.24.022469}, pages = {22469 -- 22480}, year = {2016}, abstract = {X-ray free electron lasers (XFELs) enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L-edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. However, the required x-ray bandwidth is an order of magnitude narrower than that of self-amplified spontaneous emission (SASE), and additional monochromatization is needed. Here we compare L-edge x-ray absorption spectroscopy (XAS) of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source (LCLS) with a new technique based on self-seeding of LCLS. We demonstrate how L-edge XAS can be performed using the self-seeding scheme without the need of an additional beam line monochromator. We show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x-ray spectroscopy measurements. (C) 2016 Optical Society of America}, language = {en} } @article{Kroll2015, author = {Kroll, Alexander}, title = {Explaining the Use of Performance Information by Public Managers: A Planned-Behavior Approach}, series = {The American review of public administration}, volume = {45}, journal = {The American review of public administration}, number = {2}, publisher = {Sage Publ.}, address = {Thousand Oaks}, issn = {0275-0740}, doi = {10.1177/0275074013486180}, pages = {201 -- 215}, year = {2015}, abstract = {This article examines the use of performance information by public managers. It reviews literature on the impact of attitudes and social norm and puts forward a psychological-cognitive model based on the theory of planned behavior. The article finds support for this model emphasizing that performance data use is a goal-directed, reasoned action. Another critical result is that managers who consciously intend to use performance data also make sure that the data in their division are of good quality which, in turn, fosters information use. These findings indicate thatin addition to organizational routinescognitive factors are promising starting points for interventions to foster managers' data use. The article is based on survey data from German cities.}, language = {en} } @misc{Kroll2015, author = {Kroll, Alexander}, title = {Explaining the use of performance information by public managers}, series = {American review of public administration}, journal = {American review of public administration}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-404504}, pages = {15}, year = {2015}, abstract = {This article examines the use of performance information by public managers. It reviews literature on the impact of attitudes and social norm and puts forward a psychological-cognitive model based on the theory of planned behavior. The article finds support for this model emphasizing that performance data use is a goal-directed, reasoned action. Another critical result is that managers who consciously intend to use performance data also make sure that the data in their division are of good quality which, in turn, fosters information use. These findings indicate thatin addition to organizational routinescognitive factors are promising starting points for interventions to foster managers' data use. The article is based on survey data from German cities.}, language = {en} } @article{KrollVogel2014, author = {Kroll, Alexander and Vogel, Dominik}, title = {The PSM-leadership fit: a model of performance information use}, series = {The journal of public administration}, volume = {92}, journal = {The journal of public administration}, number = {4}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0033-3298}, doi = {10.1111/padm.12014}, pages = {974 -- 991}, year = {2014}, abstract = {This article examines the use of performance information by public managers. It conceptualizes purposeful data use as a type of extra-role behaviour which requires additional effort on the part of the managers and which is not extrinsically rewarded. The article sheds light on one potential antecedent of performance information use - the motivation of the users. It argues that we can observe high levels of data use if managers driven by public service motivation (PSM) work under transformational leaders. Using a needs-supply perspective on supervisors and followers, we suggest that there is a PSM-leadership fit which fosters the performance of this extra-role behaviour. The article is based on data from German local government and its findings contribute to the literatures on PSM as well as on performance management.}, language = {en} } @misc{KrollVogel2013, author = {Kroll, Alexander and Vogel, Dominik}, title = {The PSM-leadership fit}, series = {Postprints der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe}, number = {77}, issn = {1867-5808}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-100853}, year = {2013}, abstract = {This article examines the use of performance information by public managers. It conceptualizes purposeful data use as a type of extra-role behaviour which requires additional effort on the part of the managers and which is not extrinsically rewarded. The article sheds light on one potential antecedent of performance information use - the motivation of the users. It argues that we can observe high levels of data use if managers driven by public service motivation (PSM) work under transformational leaders. Using a needs-supply perspective on supervisors and followers we suggest that there is a PSM-leadership fit which fosters the performance of this extra-role behaviour. The article is based on data from German local government and its findings contribute to the literatures on PSM as well as on performance management.}, language = {en} }