TY - JOUR A1 - Wolf, Thomas J. A. A1 - Sanchez, David M. A1 - Yang, J. A1 - Parrish, R. M. A1 - Nunes, J. P. F. A1 - Centurion, M. A1 - Coffee, R. A1 - Cryan, J. P. A1 - Gühr, Markus A1 - Hegazy, Kareem A1 - Kirrander, Adam A1 - Li, R. K. A1 - Ruddock, J. A1 - Shen, Xiaozhe A1 - Vecchione, T. A1 - Weathersby, S. P. A1 - Weber, Peter M. A1 - Wilkin, K. A1 - Yong, Haiwang A1 - Zheng, Q. A1 - Wang, X. J. A1 - Minitti, Michael P. A1 - Martinez, Todd J. T1 - The photochemical ring-opening of 1,3-cyclohexadiene imaged by ultrafast electron diffraction JF - Nature chemistry N2 - The ultrafast photoinduced ring-opening of 1,3-cyclohexadiene constitutes a textbook example of electrocyclic reactions in organic chemistry and a model for photobiological reactions in vitamin D synthesis. Although the relaxation from the photoexcited electronic state during the ring-opening has been investigated in numerous studies, the accompanying changes in atomic distance have not been resolved. Here we present a direct and unambiguous observation of the ring-opening reaction path on the femtosecond timescale and subangstrom length scale using megaelectronvolt ultrafast electron diffraction. We followed the carbon-carbon bond dissociation and the structural opening of the 1,3-cyclohexadiene ring by the direct measurement of time-dependent changes in the distribution of interatomic distances. We observed a substantial acceleration of the ring-opening motion after internal conversion to the ground state due to a steepening of the electronic potential gradient towards the product minima. The ring-opening motion transforms into rotation of the terminal ethylene groups in the photoproduct 1,3,5-hexatriene on the subpicosecond timescale. KW - Organic chemistry KW - Photochemistry KW - Physical chemistry KW - Theoretical chemistry Y1 - 2019 U6 - https://doi.org/10.1038/s41557-019-0252-7 SN - 1755-4330 SN - 1755-4349 VL - 11 IS - 6 SP - 504 EP - 509 PB - Nature Publ. Group CY - London ER - TY - JOUR A1 - Obermann, Wolfgang A1 - Gautel, Mathias A1 - Steiner, F. A1 - VanDerVen, Peter F. M. A1 - Weber, Klaus A1 - Fürst, Dieter Oswald T1 - The structure of the sarcomeric M band : localization of defined domains of myomesin, M-protein, and the 250-kD carboxy-terminal region of titin by immunoelectron microscopy Y1 - 1996 ER - TY - JOUR A1 - Malic, E. A1 - Weber, C. A1 - Richter, M. A1 - Atalla, V. A1 - Klamroth, Tillmann A1 - Saalfrank, Peter A1 - Reich, Sebastian A1 - Knorr, A. T1 - Microscopic model of the optical absorption of carbon nanotubes functionalized with molecular spiropyran photoswitches JF - Physical review letters N2 - The adsorption of molecules to the surface of carbon nanostructures opens a new field of hybrid systems with distinct and controllable properties. We present a microscopic study of the optical absorption in carbon nanotubes functionalized with molecular spiropyran photoswitches. The switching process induces a change in the dipole moment leading to a significant coupling to the charge carriers in the nanotube. As a result, the absorption spectra of functionalized tubes reveal a considerable redshift of transition energies depending on the switching state of the spiropyran molecule. Our results suggest that carbon nanotubes are excellent substrates for the optical readout of spiropyran-based molecular switches. The gained insights can be applied to other noncovalently functionalized one-dimensional nanostructures in an externally induced dipole field. Y1 - 2011 U6 - https://doi.org/10.1103/PhysRevLett.106.097401 SN - 0031-9007 VL - 106 IS - 9 PB - American Physical Society CY - College Park ER - TY - JOUR A1 - Levermann, Anders A1 - Bamber, Jonathan L. A1 - Drijfhout, Sybren A1 - Ganopolski, Andrey A1 - Haeberli, Winfried A1 - Harris, Neil R. P. A1 - Huss, Matthias A1 - Krueger, Kirstin A1 - Lenton, Timothy M. A1 - Lindsay, Ronald W. A1 - Notz, Dirk A1 - Wadhams, Peter A1 - Weber, Susanne T1 - Potential climatic transitions with profound impact on Europe Review of the current state of six 'tipping elements of the climate system' JF - Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change N2 - We discuss potential transitions of six climatic subsystems with large-scale impact on Europe, sometimes denoted as tipping elements. These are the ice sheets on Greenland and West Antarctica, the Atlantic thermohaline circulation, Arctic sea ice, Alpine glaciers and northern hemisphere stratospheric ozone. Each system is represented by co-authors actively publishing in the corresponding field. For each subsystem we summarize the mechanism of a potential transition in a warmer climate along with its impact on Europe and assess the likelihood for such a transition based on published scientific literature. As a summary, the 'tipping' potential for each system is provided as a function of global mean temperature increase which required some subjective interpretation of scientific facts by the authors and should be considered as a snapshot of our current understanding. Y1 - 2012 U6 - https://doi.org/10.1007/s10584-011-0126-5 SN - 0165-0009 SN - 1573-1480 VL - 110 IS - 3-4 SP - 845 EP - 878 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - VanDerVen, Peter F. M A1 - Obermann, Wolfgang A1 - Weber, Klaus A1 - Fürst, Dieter Oswald T1 - Myomesin, M-protein and the structure of the sarcomeric M-band Y1 - 1996 ER - TY - JOUR A1 - Obermann, Wolfgang A1 - VanDerVen, Peter F. M A1 - Steiner, F. A1 - Weber, Klaus A1 - Fürst, Dieter Oswald T1 - Mapping of a myosin binding domain and a regulatory phosphorylation site in M-protein, a structural protein of the sarcomeric M-band Y1 - 1998 ER - TY - JOUR A1 - VanDerVen, Peter F. M A1 - Obermann, Wolfgang A1 - Lemke, Britt A1 - Gautel, Mathias A1 - Weber, Klaus A1 - Fürst, Dieter Oswald T1 - The characterization of muscle filamin isoforms suggests a possible role of ABP-L/gamma-filamin in sarcomeric Z- disc formation Y1 - 2000 ER -