@article{MaassUtechtStremlauetal.2017,
  author    = {Maass, Friedrich and Utecht, Manuel Martin and Stremlau, Stephan and Gille, Marie and Schwarz, Jutta and Hecht, Stefan and Klamroth, Tillmann and Tegeder, Petra},
  title     = {Electronic structure changes during the on-surface synthesis of nitrogen-doped chevron-shaped graphene nanoribbons},
  series = {Physical review : B, Condensed matter and materials physics},
  volume    = {96},
  journal   = {Physical review : B, Condensed matter and materials physics},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {2469-9950},
  doi       = {10.1103/PhysRevB.96.045434},
  pages     = {7},
  year      = {2017},
  abstract  = {Utilizing suitable precursor molecules, a thermally activated and surface-assisted synthesis results in the formation of defect-free graphene nanoribbons (GNRs), which exhibit electronic properties that are not present in extended graphene. Most importantly, they have a band gap in the order of a few electron volts, depending on the nanoribbon width. In this study, we investigate the electronic structure changes during the formation of GNRs, nitrogen-doped (singly and doubly N-doped) as well as non-N-doped chevron-shaped CGNRs on Au(111). Thus we determine the optical gaps of the precursor molecules, the intermediate nonaromatic polymers, and finally the aromatic GNRs, using high-resolution electron energy loss spectroscopy and density functional theory calculations. As expected, we find no influence of N-doping on the size of the optical gaps. The gap of the precursor molecules is around 4.5 eV. Polymerization leads to a reduction of the gap to a value of 3.2 eV due to elongation and thus enhanced delocalization. The CGNRs exhibit a band gap of 2.8 eV, thus the gap is further reduced in the nanoribbons, since they exhibit an extended delocalized pi-electron system.},
  language  = {en}
}
@article{GouletHanssensUtechtMutrucetal.2017,
  author    = {Goulet-Hanssens, Alexis and Utecht, Manuel and Mutruc, Dragos and Titov, Evgenii and Schwarz, Jutta and Grubert, Lutz and Bleger, David and Saalfrank, Peter and Hecht, Stefan},
  title     = {Electrocatalytic Z -> E Isomerization of Azobenzenes},
  series = {Journal of the American Chemical Society},
  volume    = {139},
  journal   = {Journal of the American Chemical Society},
  number    = {1},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {0002-7863},
  doi       = {10.1021/jacs.6b10822},
  pages     = {335 -- 341},
  year      = {2017},
  abstract  = {A variety of azobenzenes were synthesized to study the behavior of their E and Z isomers upon electrochemical reduction. Our results show that the radical anion of the Z isomer is able to rapidly isomerize to the corresponding E configured counterpart with a dramatically enhanced rate as compared to the neutral species. Due to a subsequent electron transfer from the formed E radical anion to the neutral Z starting material the overall transformation is catalytic in electrons; i.e., a substoichiometric amount of reduced species can isomerize the entire mixture. This pathway greatly increases the efficiency of (photo)switching while also allowing one to reach photostationary state compositions that are not restricted to the spectral separation of the individual azobenzene isomers and their quantum yields. In addition, activating this radical isomerization pathway with photoelectron transfer agents allows us to override the intrinsic properties of an azobenzene species by triggering the reverse isomerization direction (Z -> E) by the same wavelength of light, which normally triggers E -> Z isomerization. The behavior we report appears to be general, implying that the metastable isomer of a photoswitch can be isomerized to the more stable one catalytically upon reduction, permitting the optimization of azobenzene switching in new as well as indirect ways.},
  language  = {en}
}
@article{DokicGotheWirthetal.2009,
  author    = {Dokic, Jadranka and Gothe, Marcel and Wirth, Jonas and Peters, Maike V. and Schwarz, Jutta and Hecht, Stefan and Saalfrank, Peter},
  title     = {Quantum chemical investigation of thermal cis-to-trans isomerization of azobenzene derivatives : substituent effects, solvent effects, and comparison to experimental data},
  issn      = {1089-5639},
  doi       = {10.1021/jp9021344},
  year      = {2009},
  abstract  = {Quantum chemical calculations of various azobenzene (AB) derivatives have been carried out with the goal to describe the energetics and kinetics of their thermal cis -> trans isomerization. The effects of substituents, in particular their type, number, and positioning, on activation energies have been systematically studied with the ultimate goal to tailor the switching process. Trends observed for mono- and disubstituted species are discussed. A polarizable continuum model is used to study, in an approximate fashion, the cis -> trans isomerization of azobenzenes in solution. The nature of the transition state(s) and its dependence on substituents and the environment is discussed. In particular for push-pull azobenzenes, the reaction mechanism is found to change from inversion in nonpolar solvents to rotation in polar solvents. Concerning kinetics, calculations based on the Eyring transition state theory give usually reliable activation energies and enthalpies when compared to experimentally determined values. Also, trends in the resulting rate constants are correct. Other computed properties such as activation entropies and thus preexponential rate factors are in only moderate agreement with experiment.},
  language  = {en}
}
@misc{SchwarzEtteBredekampetal.2015,
  author    = {Schwarz, Ingo and Ette, Ottmar and Bredekamp, Horst and Bispinck-Roßbacher, Julia and Kraft, Tobias and Erdmann, Dominik and Weber, Jutta and Lenz, Markus Alexander and Blankenstein, David and Savoy, B{\´e}n{\´e}dicte and Faak, Margot},
  title     = {HiN : Alexander von Humboldt im Netz = Amerikanische Reisetageb{\"u}cher},
  series = {HIN : Alexander von Humboldt im Netz ; international review for Humboldtian studies},
  volume    = {XVI},
  journal   = {HIN : Alexander von Humboldt im Netz ; international review for Humboldtian studies},
  number    = {31},
  editor    = {Ette, Ottmar and Knobloch, Eberhard},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1617-5239},
  doi       = {10.18443/hinvol16iss312015},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-89032},
  pages     = {121},
  year      = {2015},
  abstract  = {Ingo Schwarz: „etwas hervorzubringen, was meines K{\"o}nigs und meines Vaterlandes werth sein kann" - Briefe von Alexander von Humboldt an Friedrich Wilhelm III., 1805 Ottmar Ette: Tras la huella de la vida. El proyecto de larga duraci{\´o}n „Centro Alejandro de Humboldt. Ciencia en movimiento" edita los apuntes transdisciplinarios de Humboldt Horst Bredekamp: Die Amerikanischen Reisetageb{\"u}cher: ein erster Zugang Julia Bispinck-Roßbacher: „Zwischen den Zeilen …" Zur kodikologischen Untersuchung der Amerikanischen Reisetageb{\"u}cher von Alexander von Humboldt Tobias Kraft: Humboldts Hefte. Geschichte und Gegenwart von Tagebuch-Forschung und -Rezeption Dominik Erdmann, Jutta Weber: Nachlassgeschichten - Bemerkungen zu Humboldts nachgelassenen Papieren in der Berliner Staatsbibliothek und der Biblioteka Jagiellońska Krakau Bewegte Systematik. Alexander von Humboldts „Amerikanische Reisetageb{\"u}cher" als Problemfelder der Literaturgeschichte und historischen Epistemologie Markus Alexander Lenz: Bewegte Systematik. Alexander von Humboldts „Amerikanische Reisetageb{\"u}cher" als Problemfelder der Literaturgeschichte und historischen Epistemologie David Blankenstein, B{\´e}n{\´e}dicte Savoy: Frontale Pr{\"a}senz - Zu einem unbekannten Portr{\"a}t Alexander von Humboldts im Besitz des franz{\"o}sischen Conseil d'{\´E}tat Margot Faak: Alexander von Humboldts Amerikareise},
  language  = {mul}
}