Subjektivierungsforschung quo vadis? Auf holprigen Wegen zwischen Kollektiv und Individuum

Tagungsbericht zu: Jenseits der Person. Die Subjektivierung kollektiver Subjekte, 06.-08. April 2016 in Leipzig

First-principles study of the polar O-terminated ZnO surface in thermodynamic equilibrium with oxygen and hydrogen

Using density-functional theory in combination with a thermodynamic formalism we calculate the relative stability of various structural models of the polar O-terminated (000-1)-O surface of ZnO. Model surfaces with different concentrations of oxygen vacancies and hydrogen adatoms are considered. Assuming that the surfaces are in thermodynamic equilibrium with an O2 and H2 gas phase we determine a phase diagram of the lowest-energy surface structures. For a wide range of temperatures and pressures we find that hydrogen will be adsorbed at the surface, preferentially with a coverage of 1/2 monolayer. At high temperatures and low pressures the hydrogen can be removed and a structure with 1/4 of the surface oxygen atoms missing becomes the most stable one. The clean, defect-free surface can only exist in an oxygen-rich environment with a very low hydrogen partial pressure. However, since we find that the dissociative adsorption of molecular hydrogen and water (if also the Zn-terminated surface is present) is energetically very preferable, it is very unlikely that a clean, defect-free (000-1)-O surface can be observed in experiment.Comment: 10 pages, 4 postscript figures. Uses REVTEX and epsf macro

Ins Netz gegangen

Rezension zu: Ganz, Kathrin (2018): Die Netzbewegung: Subjektpositionen im politischen Diskurs der digitalen Gesellschaft. Opladen, Berlin, Toronto: Verlag Barbara Budrich, 310 Seiten. ISBN 978-3-8474-2139-9

Laser‐induced desorption of NO from NiO(100): Ab initio calculations of potential surfaces for intermediate excited states

In order to interpret the experimental results of the state resolved UV‐laser‐induced desorption of NO from NiO(100) (rotational and vibrational populations, velocity distributions of the desorbing NO molecules, etc.), we have performed ab initio complete active space self‐consistent field (CASSCF) and configuration interaction (CI) calculations for the interaction potential between NO and the NiO(100) surface in the electronic ground state and for those excited states which are involved in the desorption process. The NiO(100)–NO distance and the tilt angle between the NO axis and the surface normal have been varied. A cluster model containing a NiO8−5‐cluster embedded in a Madelung potential has been used for representing the NiO(100) surface. The excited states which are important for the desorption process, are charge transfer states of the substrate–adsorbate system, in which one electron is transferred from the surface into the NO‐2π‐orbital. The potential curves of these excited charge transfer states show deep minima (4 eV–5 eV) at surface/NO distances which are smaller than that in the ground state. The angular dependence of these potentials behaves similar as in the ground state. A semiempirical correction to the calculated excitation energies has been added which makes use of the bulk polarization of NiO. With this correction the charge transfer states are considerably stabilized. The lowest excitation energy amounts to about 4 eV which is in reasonable agreement with the onset of the laser desorption observed experimentally at about 3.5 eV. The density of the NO−‐like states is rather high, so that probably several excited states are involved in the desorption process. The potential energy curves for all of these states are quite similar, but the transitions from the ground state into different excited charge transfer states show strongly differing oscillator strengths, which are also strongly dependent on the surface/NO distance. This fact is important for the dynamics of the deexcitation process in the sense of a selection criterion for the states involved. The magnitude of the oscillator strengths is large in comparison with the excitation of NO in the gas phase, which might be an indication for the possibility of optical excitation processes. One dimensional wave packet calculations on two potential energy curves using fixed lifetimes for the excited state in each calculation have been performed and enable us to estimate the mean lifetime of the excited state to be 15 fs≤τ≤25 fs. This implies that the dynamics of the system is dominated by the attractive part of the excited state potential

Protest and the Democratic Order

The introduction of this special issue elaborates a research perspective on the meaning and function of political protest in the context of democratic orders. Starting from the consideration that protest and democratic orders form a close interrelationship, we ask how and to what extent democracy is imagined, negotiated, and problematized within protest, and how democratic orders and politics shape the formation of protest. To this end, we argue for a combination of Democratic Theory and Social Movement Studies. Interweaving these two traditions allows for empirically saturated and theoretically sound interpretations of recent episodes of contention. With this research perspective, we not only gain a deeper understanding of protest dynamics, but also of contemporary social and political transformations within modern democratic societies

Wie Städte sich neu finden

In Städten verdichten sich wie nirgendwo sonst ökonomische, soziale und kulturelle Facetten menschlichen Zusammenlebens. Hier entstehen wirtschaftliche und kulturelle Impulse. 84 Prozent der deutschen Bevölkerung lebt in Städten. Doch sind nicht alle Städte gleichermaßen Orte von Wachstum und Innovation. Mit dem Ende der Industrialisierung und dem Übergang in die Dienstleistungsgesellschaft (vgl. Bell 1999) sind einige Städte aus dem größeren Arbeits-kreislauf der Gesellschaft herausgefallen. Sie haben aufgehört, zentrale Orte des Wirtschaftens zu sein. Ihre Bevölkerungen schrumpfen, Gebäude bleiben ungenutzt und die öffentliche Hand verfügt nur über unzureichende und schwindende Mittel, dem entgegenzuwirken. Es sind strukturschwache Städte. Kommunale Schrumpfungsprozesse sind aus dem 20. Jahrhundert kaum bekannt, obwohl zwei Kriege in Deutschland tobten und unvorstellbare Verwüstungen hinterlassen haben. (...

Relationalität und dialogisches Selbst

Die meisten psychotherapeutischen Verfahren haben nach einer mehr oder weniger individualistisch orientierten Anfangsphase in den letzten Jahrzehnten eine „relationale Wende“ vollzogen und sowohl hinsichtlich ihres Menschenbildes als auch bezüglich ihrer therapeutischen Praxis die Bezogenheit des Menschen auf Andere zunehmend in den Fokus gerückt. Die dabei formulierten Konzepte von Relationalität unterscheiden sich jedoch durchaus; sie liegen, selbst innerhalb eines einzelnen Ansatzes, auf einer Achse zwischen einem „schwachen“ und einem „starken“ Verständnis menschlicher Bezogenheit. In diesem Artikel werden einige Aspekte dieser Konzepte dargestellt und in Bezug auf den Personzentrierten Ansatz diskutiert. Dabei werden die Konsequenzen herausgearbeitet, die das vom Autor vertretene Verständnis einer starken Relationalität für ein Konzept des Selbst mit sich bringen: Es ist nicht nur dialogisch, sondern auch plural konstituiert und von seinem Wesen her prozessual.Relationality and Dialogical Self. After a more or less individualistically oriented initial phase, in the past decades most psychotherapeutic approaches have performed a ‘relational turn’ and have progressively placed the relatedness of humans to others into the focus both of their image of man and of their therapeutic practice. However, the concepts of relationality that have been formulated differ quite a bit; even within a single approach they can be located on an axis between a “weak” and a “strong” understanding of human relatedness. In this paper, some aspects of these concepts are explained and discussed with respect to the personcentred approach. In addition, the consequences are pointed out which the understanding of strong relationality as it is promoted by the author brings about for the way the self is conceived of: It is not only dialogical but also plural and essentially processual

An atomic and molecular database for analysis of submillimetre line observations

Atomic and molecular data for the transitions of a number of astrophysically interesting species are summarized, including energy levels, statistical weights, Einstein A-coefficients and collisional rate coefficients. Available collisional data from quantum chemical calculations and experiments are extrapolated to higher energies. These data, which are made publically available through the WWW at http://www.strw.leidenuniv.nl/~moldata, are essential input for non-LTE line radiative transfer programs. An online version of a computer program for performing statistical equilibrium calculations is also made available as part of the database. Comparisons of calculated emission lines using different sets of collisional rate coefficients are presented. This database should form an important tool in analyzing observations from current and future (sub)millimetre and infrared telescopes.Comment: Accepted for publication in A&A, 14 pages, 5 figure

Theoretical Investigation of Laser Induced Desorption of Small Molecules from Oxide Surfaces: A First Principles Study

State resolved laser induced desorption of NO molecules from a NiO(100) surface is studied theoretically. A full potential energy surface for the excited state was constructed by means of ab initio cluster calculations in addition to the potential energy surface for the ground state. Multidimensional wave packet calculations on these two surfaces allow a detailed simulation of experimental observables, such as velocity distributions and desorption probabilities, on a full ab initio basis