@article{UtechtPanKlamrothetal.2014,
  author    = {Utecht, Manuel Martin and Pan, Tianluo and Klamroth, Tillmann and Palmer, Richard E.},
  title     = {Quantum chemical cluster models for chemi- and physisorption of chlorobenzene on Si(111)-7x7},
  series = {The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment \& general theory},
  volume    = {118},
  journal   = {The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment \& general theory},
  number    = {33},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1089-5639},
  doi       = {10.1021/jp504208d},
  pages     = {6699 -- 6704},
  year      = {2014},
  abstract  = {Motivated by recent atomic manipulation experiments, we report quantum chemical calculations for chemi- and physisorption minima of chlorobenzene on the Si(111)-7x7 surface. A density functional theory cluster approach is applied, using the B3LYP hybrid functional alongside Grimme's empirical dispersion corrections (D3). We were able to identify chemisorption sites of binding energies of 1.6 eV and physisorption energies of 0.6 eV, both in encouraging agreement with the trend of experimental data. The cluster approach opens up the possibility of a first-principles based dynamical description of STM manipulation experiments on this system, the interpretation of which involves both the chemi- and physisorbed states. However, we found that special care has to be taken regarding the choice of clusters, basis sets, and the evaluation of the dispersion corrections.},
  language  = {en}
}
@article{BronnerUtechtHaaseetal.2014,
  author    = {Bronner, Christopher and Utecht, Manuel Martin and Haase, Anton and Saalfrank, Peter and Klamroth, Tillmann and Tegeder, Petra},
  title     = {Electronic structure changes during the surface-assisted formation of a graphene nanoribbon},
  series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  volume    = {140},
  journal   = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  number    = {2},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-9606},
  doi       = {10.1063/1.4858855},
  pages     = {7},
  year      = {2014},
  abstract  = {High conductivity and a tunability of the band gap make quasi-one-dimensional graphene nanoribbons (GNRs) highly interesting materials for the use in field effect transistors. Especially bottom-up fabricated GNRs possess well-defined edges which is important for the electronic structure and accordingly the band gap. In this study we investigate the formation of a sub-nanometer wide armchair GNR generated on a Au(111) surface. The on-surface synthesis is thermally activated and involves an intermediate non-aromatic polymer in which the molecular precursor forms polyanthrylene chains. Employing angle-resolved two-photon photoemission in combination with density functional theory calculations we find that the polymer exhibits two dispersing states which we attribute to the valence and the conduction band, respectively. While the band gap of the non-aromatic polymer obtained in this way is relatively large, namely 5.25 +/- 0.06 eV, the gap of the corresponding aromatic GNR is strongly reduced which we attribute to the different degree of electron delocalization in the two systems.},
  language  = {en}
}
@article{KnieUtechtZhaoetal.2014,
  author    = {Knie, Christopher and Utecht, Manuel Martin and Zhao, Fangli and Kulla, Hannes and Kovalenko, Sergey and Brouwer, Albert M. and Saalfrank, Peter and Hecht, Stefan and Bleger, David},
  title     = {ortho-Fluoroazobenzenes: visible light switches with very long-lived Z isomers},
  series = {Chemistry - a European journal},
  volume    = {20},
  journal   = {Chemistry - a European journal},
  number    = {50},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.201404649},
  pages     = {16492 -- 16501},
  year      = {2014},
  abstract  = {Improving the photochemical properties of molecular photoswitches is crucial for the development of light-responsive systems in materials and life sciences. ortho-Fluoroazobenzenes are a new class of rationally designed photochromic azo compounds with optimized properties, such as the ability to isomerize with visible light only, high photoconversions, and unprecedented robust bistable character. Introducing sigma-electron-withdrawing F atoms ortho to the N=N unit leads to both an effective separation of the n -> pi* bands of the E and Z isomers, thus offering the possibility of using these two transitions for selectively inducing E/Z iso-merizations, and greatly enhanced thermal stability of the Z isomers. Additional para-electron-withdrawing groups (EWGs) work in concert with ortho-F atoms, giving rise to enhanced separation of the n -> pi* transitions. A comprehensive study of the effect of substitution on the key photochemical properties of ortho-fluoroazobenzenes is reported herein. In particular, the position, number, and nature of the EWGs have been varied, and the visible light photoconversions, quantum yields of isomerization, and thermal stabilities have been measured and rationalized by DFT calculations.},
  language  = {en}
}