TY  - JOUR
A1  - Xin, Hong
A1  - LaRue, Jerry
A1  - Oberg, Henrik
A1  - Beye, Martin
A1  - Turner, J. J.
A1  - Gladh, Jörgen
A1  - Ng, May L.
A1  - Sellberg, Jonas A.
A1  - Kaya, Sarp
A1  - Mercurio, G.
A1  - Hieke, F.
A1  - Nordlund, Dennis
A1  - Schlotter, William F.
A1  - Dakovski, Georgi L.
A1  - Minitti, Michael P.
A1  - Föhlisch, Alexander
A1  - Wolf, Martin
A1  - Wurth, Wilfried
A1  - Ogasawara, Hirohito
A1  - Norskov, Jens K.
A1  - Ostrom, Henrik
A1  - Pettersson, Lars G. M.
A1  - Nilsson, Anders
A1  - Abild-Pedersen, Frank
T1  - Strong Influence of Coadsorbate Interaction on CO Desorption Dynamics on Ru(0001) Probed by Ultrafast X-Ray Spectroscopy and Ab Initio Simulations
JF  - Physical review letters
N2  - We show that coadsorbed oxygen atoms have a dramatic influence on the CO desorption dynamics from Ru(0001). In contrast to the precursor-mediated desorption mechanism on Ru(0001), the presence of surface oxygen modifies the electronic structure of Ru atoms such that CO desorption occurs predominantly via the direct pathway. This phenomenon is directly observed in an ultrafast pump-probe experiment using a soft x-ray free-electron laser to monitor the dynamic evolution of the valence electronic structure of the surface species. This is supported with the potential of mean force along the CO desorption path obtained from density-functional theory calculations. Charge density distribution and frozen-orbital analysis suggest that the oxygen-induced reduction of the Pauli repulsion, and consequent increase of the dative interaction between the CO 5 sigma and the charged Ru atom, is the electronic origin of the distinct desorption dynamics. Ab initio molecular dynamics simulations of CO desorption from Ru(0001) and oxygen-coadsorbed Ru(0001) provide further insights into the surface bond-breaking process.
Y1  - 2015
U6  - https://doi.org/10.1103/PhysRevLett.114.156101
SN  - 0031-9007
SN  - 1079-7114
VL  - 114
IS  - 15
PB  - American Physical Society
CY  - College Park
ER  - 
TY  - JOUR
A1  - Oberg, H.
A1  - Gladh, Jörgen
A1  - Anniyev, Toyli
A1  - Beye, Martin
A1  - Coffee, Ryan
A1  - Föhlisch, Alexander
A1  - Katayama, T.
A1  - Kaya, Sarp
A1  - LaRue, Jerry
A1  - Mogelhoj, Andreas
A1  - Nordlund, Dennis
A1  - Ogasawara, Hirohito
A1  - Schlotter, William F.
A1  - Sellberg, Jonas A.
A1  - Sorgenfrei, Florian
A1  - Turner, Joshua J.
A1  - Wolf, Martin
A1  - Wurth, W.
A1  - Ostrom, Henrik
A1  - Nilsson, Anders
A1  - Norskov, Jens K.
A1  - Pettersson, Lars G. M.
T1  - Optical laser-induced CO desorption from Ru(0001) monitored with a free-electron X-ray laser: DFT prediction and X-ray confirmation of a precursor state
JF  - Surface science
N2  - We present density functional theory modeling of time-resolved optical pump/X-ray spectroscopic probe data of CO desorption from Ru(0001). The BEEF van der Waals functional predicts a weakly bound state as a precursor to desorption. The optical pump leads to a near-instantaneous (<100 fs) increase of the electronic temperature to nearly 7000 K. The temperature evolution and energy transfer between electrons, substrate phonons and adsorbate is described by the two-temperature model and found to equilibrate on a timescale of a few picoseconds to an elevated local temperature of similar to 2000K. Estimating the free energy based on the computed potential of mean force along the desorption path, we find an entropic barrier to desorption (and by time-reversal also to adsorption). This entropic barrier separates the chemisorbed and precursor states, and becomes significant at the elevated temperature of the experiment (similar to 1.4 eV at 2000 K). Experimental pump-probe X-ray absorption/X-ray emission spectroscopy indicates population of a precursor state to desorption upon laser-excitation of the system (Dell'Angela et al., 2013). Computing spectra along the desorption path confirms the picture of a weakly bound transient state arising from ultrafast heating of the metal substrate. (C) 2015 Elsevier B.V. All rights reserved.
KW  - CO desorption
KW  - Potential of mean force
KW  - Two-temperature model
KW  - Pump-probe
KW  - X-ray spectroscopy
KW  - Density functional theory
Y1  - 2015
U6  - https://doi.org/10.1016/j.susc.2015.03.011
SN  - 0039-6028
SN  - 1879-2758
VL  - 640
SP  - 80
EP  - 88
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Janssen, Annette B. G.
A1  - Arhonditsis, George B.
A1  - Beusen, Arthur
A1  - Bolding, Karsten
A1  - Bruce, Louise
A1  - Bruggeman, Jorn
A1  - Couture, Raoul-Marie
A1  - Downing, Andrea S.
A1  - Elliott, J. Alex
A1  - Frassl, Marieke A.
A1  - Gal, Gideon
A1  - Gerla, Daan J.
A1  - Hipsey, Matthew R.
A1  - Hu, Fenjuan
A1  - Ives, Stephen C.
A1  - Janse, Jan H.
A1  - Jeppesen, Erik
A1  - Joehnk, Klaus D.
A1  - Kneis, David
A1  - Kong, Xiangzhen
A1  - Kuiper, Jan J.
A1  - Lehmann, Moritz K.
A1  - Lemmen, Carsten
A1  - Oezkundakci, Deniz
A1  - Petzoldt, Thomas
A1  - Rinke, Karsten
A1  - Robson, Barbara J.
A1  - Sachse, Rene
A1  - Schep, Sebastiaan A.
A1  - Schmid, Martin
A1  - Scholten, Huub
A1  - Teurlincx, Sven
A1  - Trolle, Dennis
A1  - Troost, Tineke A.
A1  - Van Dam, Anne A.
A1  - Van Gerven, Luuk P. A.
A1  - Weijerman, Mariska
A1  - Wells, Scott A.
A1  - Mooij, Wolf M.
T1  - Exploring, exploiting and evolving diversity of aquatic ecosystem models: a community perspective
JF  - Aquatic ecology : the international forum covering research in freshwater and marine environments
N2  - Here, we present a community perspective on how to explore, exploit and evolve the diversity in aquatic ecosystem models. These models play an important role in understanding the functioning of aquatic ecosystems, filling in observation gaps and developing effective strategies for water quality management. In this spirit, numerous models have been developed since the 1970s. We set off to explore model diversity by making an inventory among 42 aquatic ecosystem modellers, by categorizing the resulting set of models and by analysing them for diversity. We then focus on how to exploit model diversity by comparing and combining different aspects of existing models. Finally, we discuss how model diversity came about in the past and could evolve in the future. Throughout our study, we use analogies from biodiversity research to analyse and interpret model diversity. We recommend to make models publicly available through open-source policies, to standardize documentation and technical implementation of models, and to compare models through ensemble modelling and interdisciplinary approaches. We end with our perspective on how the field of aquatic ecosystem modelling might develop in the next 5-10 years. To strive for clarity and to improve readability for non-modellers, we include a glossary.
KW  - Water quality
KW  - Ecology
KW  - Geochemistry
KW  - Hydrology
KW  - Hydraulics
KW  - Hydrodynamics
KW  - Physical environment
KW  - Socio-economics
KW  - Model availability
KW  - Standardization
KW  - Linking
Y1  - 2015
U6  - https://doi.org/10.1007/s10452-015-9544-1
SN  - 1386-2588
SN  - 1573-5125
VL  - 49
IS  - 4
SP  - 513
EP  - 548
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Dell'Angela, Martina
A1  - Anniyev, Toyli
A1  - Beye, Martin
A1  - Coffee, Ryan
A1  - Föhlisch, Alexander
A1  - Gladh, Jörgen
A1  - Kaya, Sarp
A1  - Katayama, Tetsuo
A1  - Krupin, Oleg
A1  - Nilsson, Anders
A1  - Nordlund, Dennis
A1  - Schlotter, William F.
A1  - Sellberg, Jonas A.
A1  - Sorgenfrei, Florian
A1  - Turner, Joshua J.
A1  - ÖstrÖm, Henrik
A1  - Ogasawara, Hirohito
A1  - Wolf, Martin
A1  - Wurth, Wilfried
T1  - Vacuum space charge effects in sub-picosecond soft X-ray photoemission on a molecular adsorbate layer
JF  - Structural dynamics
N2  - Vacuum space charge induced kinetic energy shifts of O 1s and Ru 3d core levels in femtosecond soft X-ray photoemission spectra (PES) have been studied at a free electron laser (FEL) for an oxygen layer on Ru(0001). We fully reproduced the measurements by simulating the in-vacuum expansion of the photoelectrons and demonstrate the space charge contribution of the high-order harmonics in the FEL beam. Employing the same analysis for 400 nm pump-X-ray probe PES, we can disentangle the delay dependent Ru 3d energy shifts into effects induced by space charge and by lattice heating from the femtosecond pump pulse. (C) 2015 Author(s).
Y1  - 2015
U6  - https://doi.org/10.1063/1.4914892
SN  - 2329-7778
VL  - 2
IS  - 2
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Holz, Nathalie E.
A1  - Boecker-Schlier, Regina
A1  - Hohm, Erika
A1  - Zohsel, Katrin
A1  - Buchmann, Arlette F.
A1  - Blomeyer, Dorothea
A1  - Jennen-Steinmetz, Christine
A1  - Baumeister, Sarah
A1  - Hohmann, Sarah
A1  - Wolf, Isabella
A1  - Plichta, Michael M.
A1  - Esser, Günter
A1  - Schmidt, Martin
A1  - Meyer-Lindenberg, Andreas
A1  - Banaschewski, Tobias
A1  - Brandeis, Daniel
A1  - Laucht, Manfred
T1  - The Long-Term Impact of Early Life Poverty on Orbitofrontal Cortex Volume in Adulthood: Results from a Prospective Study Over 25 Years
JF  - Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
N2  - Converging evidence has highlighted the association between poverty and conduct disorder (CD) without specifying neurobiological pathways. Neuroimaging research has emphasized structural and functional alterations in the orbitofrontal cortex (OFC) as one key mechanism underlying this disorder. The present study aimed to clarify the long-term influence of early poverty on OFC volume and its association with CD symptoms in healthy participants of an epidemiological cohort study followed since birth. At age 25 years, voxel-based morphometry was applied to study brain volume differences. Poverty (0 = non-exposed (N = 134), I = exposed (N = 33)) and smoking during pregnancy were determined using a standardized parent interview, and information on maternal responsiveness was derived from videotaped mother infant interactions at the age of 3 months. CD symptoms were assessed by diagnostic interview from 8 to 19 years of age. Information on life stress was acquired at each assessment and childhood maltreatment was measured using retrospective self-report at the age of 23 years. Analyses were adjusted for sex, parental psychopathology and delinquency, obstetric adversity, parental education, and current poverty. Individuals exposed to early life poverty exhibited a lower OFC volume. Moreover, we replicated previous findings of increased CD symptoms as a consequence of childhood poverty. This effect proved statistically mediated by OFC volume and exposure to life stress and smoking during pregnancy, but not by childhood maltreatment and maternal responsiveness. These findings underline the importance of studying the impact of early life adversity on brain alterations and highlight the need for programs to decrease income-related disparities.
Y1  - 2015
U6  - https://doi.org/10.1038/npp.2014.277
SN  - 0893-133X
SN  - 1740-634X
VL  - 40
IS  - 4
SP  - 996
EP  - 1004
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Aarts, Alexander A.
A1  - Anderson, Joanna E.
A1  - Anderson, Christopher J.
A1  - Attridge, Peter R.
A1  - Attwood, Angela
A1  - Axt, Jordan
A1  - Babel, Molly
A1  - Bahnik, Stepan
A1  - Baranski, Erica
A1  - Barnett-Cowan, Michael
A1  - Bartmess, Elizabeth
A1  - Beer, Jennifer
A1  - Bell, Raoul
A1  - Bentley, Heather
A1  - Beyan, Leah
A1  - Binion, Grace
A1  - Borsboom, Denny
A1  - Bosch, Annick
A1  - Bosco, Frank A.
A1  - Bowman, Sara D.
A1  - Brandt, Mark J.
A1  - Braswell, Erin
A1  - Brohmer, Hilmar
A1  - Brown, Benjamin T.
A1  - Brown, Kristina
A1  - Bruening, Jovita
A1  - Calhoun-Sauls, Ann
A1  - Callahan, Shannon P.
A1  - Chagnon, Elizabeth
A1  - Chandler, Jesse
A1  - Chartier, Christopher R.
A1  - Cheung, Felix
A1  - Christopherson, Cody D.
A1  - Cillessen, Linda
A1  - Clay, Russ
A1  - Cleary, Hayley
A1  - Cloud, Mark D.
A1  - Cohn, Michael
A1  - Cohoon, Johanna
A1  - Columbus, Simon
A1  - Cordes, Andreas
A1  - Costantini, Giulio
A1  - Alvarez, Leslie D. Cramblet
A1  - Cremata, Ed
A1  - Crusius, Jan
A1  - DeCoster, Jamie
A1  - DeGaetano, Michelle A.
A1  - Della Penna, Nicolas
A1  - den Bezemer, Bobby
A1  - Deserno, Marie K.
A1  - Devitt, Olivia
A1  - Dewitte, Laura
A1  - Dobolyi, David G.
A1  - Dodson, Geneva T.
A1  - Donnellan, M. Brent
A1  - Donohue, Ryan
A1  - Dore, Rebecca A.
A1  - Dorrough, Angela
A1  - Dreber, Anna
A1  - Dugas, Michelle
A1  - Dunn, Elizabeth W.
A1  - Easey, Kayleigh
A1  - Eboigbe, Sylvia
A1  - Eggleston, Casey
A1  - Embley, Jo
A1  - Epskamp, Sacha
A1  - Errington, Timothy M.
A1  - Estel, Vivien
A1  - Farach, Frank J.
A1  - Feather, Jenelle
A1  - Fedor, Anna
A1  - Fernandez-Castilla, Belen
A1  - Fiedler, Susann
A1  - Field, James G.
A1  - Fitneva, Stanka A.
A1  - Flagan, Taru
A1  - Forest, Amanda L.
A1  - Forsell, Eskil
A1  - Foster, Joshua D.
A1  - Frank, Michael C.
A1  - Frazier, Rebecca S.
A1  - Fuchs, Heather
A1  - Gable, Philip
A1  - Galak, Jeff
A1  - Galliani, Elisa Maria
A1  - Gampa, Anup
A1  - Garcia, Sara
A1  - Gazarian, Douglas
A1  - Gilbert, Elizabeth
A1  - Giner-Sorolla, Roger
A1  - Glöckner, Andreas
A1  - Göllner, Lars
A1  - Goh, Jin X.
A1  - Goldberg, Rebecca
A1  - Goodbourn, Patrick T.
A1  - Gordon-McKeon, Shauna
A1  - Gorges, Bryan
A1  - Gorges, Jessie
A1  - Goss, Justin
A1  - Graham, Jesse
A1  - Grange, James A.
A1  - Gray, Jeremy
A1  - Hartgerink, Chris
A1  - Hartshorne, Joshua
A1  - Hasselman, Fred
A1  - Hayes, Timothy
A1  - Heikensten, Emma
A1  - Henninger, Felix
A1  - Hodsoll, John
A1  - Holubar, Taylor
A1  - Hoogendoorn, Gea
A1  - Humphries, Denise J.
A1  - Hung, Cathy O. -Y.
A1  - Immelman, Nathali
A1  - Irsik, Vanessa C.
A1  - Jahn, Georg
A1  - Jaekel, Frank
A1  - Jekel, Marc
A1  - Johannesson, Magnus
A1  - Johnson, Larissa G.
A1  - Johnson, David J.
A1  - Johnson, Kate M.
A1  - Johnston, William J.
A1  - Jonas, Kai
A1  - Joy-Gaba, Jennifer A.
A1  - Kappes, Heather Barry
A1  - Kelso, Kim
A1  - Kidwell, Mallory C.
A1  - Kim, Seung Kyung
A1  - Kirkhart, Matthew
A1  - Kleinberg, Bennett
A1  - Knezevic, Goran
A1  - Kolorz, Franziska Maria
A1  - Kossakowski, Jolanda J.
A1  - Krause, Robert Wilhelm
A1  - Krijnen, Job
A1  - Kuhlmann, Tim
A1  - Kunkels, Yoram K.
A1  - Kyc, Megan M.
A1  - Lai, Calvin K.
A1  - Laique, Aamir
A1  - Lakens, Daniel
A1  - Lane, Kristin A.
A1  - Lassetter, Bethany
A1  - Lazarevic, Ljiljana B.
A1  - LeBel, Etienne P.
A1  - Lee, Key Jung
A1  - Lee, Minha
A1  - Lemm, Kristi
A1  - Levitan, Carmel A.
A1  - Lewis, Melissa
A1  - Lin, Lin
A1  - Lin, Stephanie
A1  - Lippold, Matthias
A1  - Loureiro, Darren
A1  - Luteijn, Ilse
A1  - Mackinnon, Sean
A1  - Mainard, Heather N.
A1  - Marigold, Denise C.
A1  - Martin, Daniel P.
A1  - Martinez, Tylar
A1  - Masicampo, E. J.
A1  - Matacotta, Josh
A1  - Mathur, Maya
A1  - May, Michael
A1  - Mechin, Nicole
A1  - Mehta, Pranjal
A1  - Meixner, Johannes
A1  - Melinger, Alissa
A1  - Miller, Jeremy K.
A1  - Miller, Mallorie
A1  - Moore, Katherine
A1  - Möschl, Marcus
A1  - Motyl, Matt
A1  - Müller, Stephanie M.
A1  - Munafo, Marcus
A1  - Neijenhuijs, Koen I.
A1  - Nervi, Taylor
A1  - Nicolas, Gandalf
A1  - Nilsonne, Gustav
A1  - Nosek, Brian A.
A1  - Nuijten, Michele B.
A1  - Olsson, Catherine
A1  - Osborne, Colleen
A1  - Ostkamp, Lutz
A1  - Pavel, Misha
A1  - Penton-Voak, Ian S.
A1  - Perna, Olivia
A1  - Pernet, Cyril
A1  - Perugini, Marco
A1  - Pipitone, R. Nathan
A1  - Pitts, Michael
A1  - Plessow, Franziska
A1  - Prenoveau, Jason M.
A1  - Rahal, Rima-Maria
A1  - Ratliff, Kate A.
A1  - Reinhard, David
A1  - Renkewitz, Frank
A1  - Ricker, Ashley A.
A1  - Rigney, Anastasia
A1  - Rivers, Andrew M.
A1  - Roebke, Mark
A1  - Rutchick, Abraham M.
A1  - Ryan, Robert S.
A1  - Sahin, Onur
A1  - Saide, Anondah
A1  - Sandstrom, Gillian M.
A1  - Santos, David
A1  - Saxe, Rebecca
A1  - Schlegelmilch, Rene
A1  - Schmidt, Kathleen
A1  - Scholz, Sabine
A1  - Seibel, Larissa
A1  - Selterman, Dylan Faulkner
A1  - Shaki, Samuel
A1  - Simpson, William B.
A1  - Sinclair, H. Colleen
A1  - Skorinko, Jeanine L. M.
A1  - Slowik, Agnieszka
A1  - Snyder, Joel S.
A1  - Soderberg, Courtney
A1  - Sonnleitner, Carina
A1  - Spencer, Nick
A1  - Spies, Jeffrey R.
A1  - Steegen, Sara
A1  - Stieger, Stefan
A1  - Strohminger, Nina
A1  - Sullivan, Gavin B.
A1  - Talhelm, Thomas
A1  - Tapia, Megan
A1  - te Dorsthorst, Anniek
A1  - Thomae, Manuela
A1  - Thomas, Sarah L.
A1  - Tio, Pia
A1  - Traets, Frits
A1  - Tsang, Steve
A1  - Tuerlinckx, Francis
A1  - Turchan, Paul
A1  - Valasek, Milan
A1  - Van Aert, Robbie
A1  - van Assen, Marcel
A1  - van Bork, Riet
A1  - van de Ven, Mathijs
A1  - van den Bergh, Don
A1  - van der Hulst, Marije
A1  - van Dooren, Roel
A1  - van Doorn, Johnny
A1  - van Renswoude, Daan R.
A1  - van Rijn, Hedderik
A1  - Vanpaemel, Wolf
A1  - Echeverria, Alejandro Vasquez
A1  - Vazquez, Melissa
A1  - Velez, Natalia
A1  - Vermue, Marieke
A1  - Verschoor, Mark
A1  - Vianello, Michelangelo
A1  - Voracek, Martin
A1  - Vuu, Gina
A1  - Wagenmakers, Eric-Jan
A1  - Weerdmeester, Joanneke
A1  - Welsh, Ashlee
A1  - Westgate, Erin C.
A1  - Wissink, Joeri
A1  - Wood, Michael
A1  - Woods, Andy
A1  - Wright, Emily
A1  - Wu, Sining
A1  - Zeelenberg, Marcel
A1  - Zuni, Kellylynn
T1  - Estimating the reproducibility of psychological science
JF  - Science
N2  - Reproducibility is a defining feature of science, but the extent to which it characterizes current research is unknown. We conducted replications of 100 experimental and correlational studies published in three psychology journals using high-powered designs and original materials when available. Replication effects were half the magnitude of original effects, representing a substantial decline. Ninety-seven percent of original studies had statistically significant results. Thirty-six percent of replications had statistically significant results; 47% of original effect sizes were in the 95% confidence interval of the replication effect size; 39% of effects were subjectively rated to have replicated the original result; and if no bias in original results is assumed, combining original and replication results left 68% with statistically significant effects. Correlational tests suggest that replication success was better predicted by the strength of original evidence than by characteristics of the original and replication teams.
Y1  - 2015
U6  - https://doi.org/10.1126/science.aac4716
SN  - 1095-9203
SN  - 0036-8075
VL  - 349
IS  - 6251
PB  - American Assoc. for the Advancement of Science
CY  - Washington
ER  - 
TY  - JOUR
A1  - Ostrom, H.
A1  - Oberg, H.
A1  - Xin, H.
A1  - Larue, J.
A1  - Beye, Martin
A1  - Gladh, J.
A1  - Ng, M. L.
A1  - Sellberg, J. A.
A1  - Kaya, S.
A1  - Mercurio, G.
A1  - Nordlund, D.
A1  - Hantschmann, Markus
A1  - Hieke, F.
A1  - Kuehn, D.
A1  - Schlotter, W. F.
A1  - Dakovski, G. L.
A1  - Turner, J. J.
A1  - Minitti, M. P.
A1  - Mitra, A.
A1  - Moeller, S. P.
A1  - Föhlisch, Alexander
A1  - Wolf, M.
A1  - Wurth, W.
A1  - Persson, Mats
A1  - Norskov, J. K.
A1  - Abild-Pedersen, Frank
A1  - Ogasawara, Hirohito
A1  - Pettersson, Lars G. M.
A1  - Nilsson, A.
T1  - Probing the transition state region in catalytic CO oxidation on Ru
JF  - Science
N2  - Femtosecond x-ray laser pulses are used to probe the carbon monoxide (CO) oxidation reaction on ruthenium (Ru) initiated by an optical laser pulse. On a time scale of a few hundred femtoseconds, the optical laser pulse excites motions of CO and oxygen (O) on the surface, allowing the reactants to collide, and, with a transient close to a picosecond (ps), new electronic states appear in the OK-edge x-ray absorption spectrum. Density functional theory calculations indicate that these result from changes in the adsorption site and bond formation between CO and O with a distribution of OC-O bond lengths close to the transition state (TS). After 1 ps, 10% of the CO populate the TS region, which is consistent with predictions based on a quantum oscillator model.
Y1  - 2015
U6  - https://doi.org/10.1126/science.1261747
SN  - 0036-8075
SN  - 1095-9203
VL  - 347
IS  - 6225
SP  - 978
EP  - 982
PB  - American Assoc. for the Advancement of Science
CY  - Washington
ER  - 
TY  - JOUR
A1  - Tong, Yujin
A1  - Wirth, Jonas
A1  - Kirsch, Harald
A1  - Wolf, Martin
A1  - Saalfrank, Peter
A1  - Campen, Richard Kramer
T1  - Optically probing Al-O and O-H vibrations to characterize water adsorption and surface reconstruction on alpha-alumina: An experimental and theoretical study
JF  - The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr
N2  - Oxide/water interfaces are ubiquitous in a wide variety of applications and the environment. Despite this ubiquity, and attendant decades of study, gaining molecular level insight into water/oxide interaction has proven challenging. In part, this challenge springs from a lack of tools to concurrently characterize changes in surface structure (i.e., water/oxide interaction from the perspective of the solid) and O-H population and local environment (i.e., water/oxide interaction from the water perspective). Here, we demonstrate the application of surface specific vibrational spectroscopy to the characterization of the interaction of the paradigmatic alpha-Al2O3(0001) surface and water. By probing both the interfacial Al-O (surface phonon) and O-H spectral response, we characterize this interaction from both perspectives. Through electronic structure calculation, we assign the interfacial Al-O response and rationalize its changes on surface dehydroxylation and reconstruction. Because our technique is all-optical and interface specific, it is equally applicable to oxide surfaces in vacuum, ambient atmospheres and at the solid/liquid interface. Application of this approach to additional alumina surfaces and other oxides thus seems likely to significantly expand our understanding of how water meets oxide surfaces and thus the wide variety of phenomena this interaction controls. (C) 2015 AIP Publishing LLC.
Y1  - 2015
U6  - https://doi.org/10.1063/1.4906346
SN  - 0021-9606
SN  - 1089-7690
VL  - 142
IS  - 5
PB  - American Institute of Physics
CY  - Melville
ER  - 
TY  - JOUR
A1  - Toala, Jesús Alberto
A1  - Guerrero, Martín A.
A1  - Todt, Helge Tobias
A1  - Hamann, Wolf-Rainer
A1  - Chu, Y.-H.
A1  - Gruendl, R. A.
A1  - Schönberner, Detlef
A1  - Oskinova, Lida
A1  - Marquez-Lugo, R. A.
A1  - Fang, X.
A1  - Ramos-Larios, Gerardo
T1  - The born-again Planetary nebula A78: an X-RAY twin of A30
JF  - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2  - We present the XMM-Newton discovery of X-ray emission from the planetary nebula (PN) A78, the second born-again PN detected in X-rays apart from A30. These two PNe share similar spectral and morphological characteristics: they harbor diffuse soft X-ray emission associated with the interaction between the H-poor ejecta and the current fast stellar wind and a point-like source at the position of the central star (CSPN). We present the spectral analysis of the CSPN, using for the first time an NLTE code for expanding atmospheres that takes line blanketing into account for the UV and optical spectra. The wind abundances are used for the X-ray spectral analysis of the CSPN and the diffuse emission. The X-ray emission from the CSPN in A78 can be modeled by a single C VI emission line, while the X-ray emission from its diffuse component is better described by an optically thin plasma emission model with a temperature of kT = 0.088 keV (T approximate to 1.0 x 10(6) K). We estimate X-ray luminosities in the 0.2-2.0 keV energy band of L-X,L-CSPN =(1.2 +/- 0.3) x 10(31) erg s(-1) and L-X,L-DIFF =(9.2 +/- 2.3) x 10(30) erg s(-1) for the CSPN and diffuse components, respectively.
KW  - planetary nebulae: general
KW  - planetary nebulae: individual (A78)
KW  - stars: winds, outflows
KW  - X-rays: ISM
Y1  - 2015
U6  - https://doi.org/10.1088/0004-637X/799/1/67
SN  - 0004-637X
SN  - 1538-4357
VL  - 799
IS  - 1
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -