@article{NacciFoelschZenichowskietal.2009,
  author    = {Nacci, Christophe and Foelsch, Stefan and Zenichowski, Karl and Dokic, Jadranka and Klamroth, Tillmann and Saalfrank, Peter},
  title     = {Current versus temperature-induced switching in a single-molecule tunnel junction : 1,5 cyclooctadiene on Si(001)},
  issn      = {1530-6984},
  doi       = {10.1021/Nl901419g},
  year      = {2009},
  abstract  = {The biconformational switching of single cyclooctadiene molecules chemisorbed on a Si(001) surface was explored by quantum chemical and quantum dynamical calculations and low-temperature scanning tunneling microscopy experiments. The calculations rationalize the experimentally observed switching driven by inelastic electron tunneling (IET) at 5 K. At higher temperatures, they predict a controllable crossover behavior between IET-driven and thermally activated switching, which is fully confirmed by experiment.},
  language  = {en}
}
@article{ZenichowskiDokicKlamrothetal.2012,
  author    = {Zenichowski, Karl and Dokic, Jadranka and Klamroth, Tillmann and Saalfrank, Peter},
  title     = {Current versus temperature-induced switching of a single molecule - open-system density matrix theory for 1,5-cyclooctadiene on Si(100)},
  series = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  volume    = {136},
  journal   = {The journal of chemical physics : bridges a gap between journals of physics and journals of chemistr},
  number    = {9},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {0021-9606},
  doi       = {10.1063/1.3692229},
  pages     = {13},
  year      = {2012},
  abstract  = {The switching of single cyclooctadiene molecules chemisorbed on a Si(100) surface between two stable conformations, can be achieved with a scanning tunneling microscope [Nacci , Phys. Rev. B 77, 121405(R) (2008)]. Recently, it was shown by quantum chemical and quantum dynamical simulations that major experimental facts can be explained by a single-mode model with switching enforced by inelastic electron tunneling (IET) excitations and perturbed by vibrational relaxation [Nacci , Nano Lett. 9, 2997 (2009)]. In the present paper, we extend the previous theoretical work in several respects: (1) The model is generalized to a two-mode description in which two C2H4 units of COD can move independently; (2) contributions of dipole and, in addition, (cation and anion) resonance-IET rates are considered; (3) the harmonic-linear vibrational relaxation model used previously is generalized to anharmonic vibrations. While the present models highlight generic aspects of IET-switching between two potential minima, they also rationalize specific experimental findings for COD/Si(100): (1) A single-electron excitation mechanism with a linear dependence of the switching rate on tunneling current I, (2) the capability to switch both at negative and positive sample biases, and (3) a crossover temperature around similar to 60 K from an IET-driven, T-independent atom tunneling regime, to classical over-the-barrier isomerization with exponential T-dependence at higher temperatures for a bias voltage of +1.5 V and an average tunneling current of 0.73 nA.},
  language  = {en}
}
@article{FuechselKlamrothDokicetal.2006,
  author    = {F{\"u}chsel, Gernot and Klamroth, Tillmann and Dokic, Jadranka and Saalfrank, Peter},
  title     = {On the electronic structure of neutral and ionic azobenzenes and their possible role as surface mounted molecular switches},
  series = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  volume    = {110},
  journal   = {The journal of physical chemistry : B, Condensed matter, materials, surfaces, interfaces \& biophysical chemistry},
  number    = {33},
  publisher = {Soc.},
  address   = {Washington},
  issn      = {1520-6106},
  doi       = {10.1021/jp060969v},
  pages     = {16337 -- 16345},
  year      = {2006},
  abstract  = {We report quantum chemical calculations, mostly based on density functional theory, on azobenzene and substituted azobenzenes as neutral molecules or ions, in ground and excited states. Both the cis and trans configurations are computed as well as the activation energies to transform one isomer into the other and the possible reaction paths and reaction surfaces along the torsion and inversion modes. All calculations are done for the isolated species, but results are discussed in light of recent experiments aiming at the switching of surface mounted azobenzenes by scanning tunneling microscopes.},
  language  = {en}
}
@article{ZenichowskiNacciFoelschetal.2012,
  author    = {Zenichowski, Karl and Nacci, Ch and F{\"o}lsch, S. and Dokic, Jadranka and Klamroth, Tillmann and Saalfrank, Peter},
  title     = {STM-switching of organic molecules on semiconductor surfaces: an above threshold density matrix model for 1,5 cyclooctadiene on Si(100)},
  series = {Journal of physics : Condensed matter},
  volume    = {24},
  journal   = {Journal of physics : Condensed matter},
  number    = {39},
  publisher = {IOP Publ. Ltd.},
  address   = {Bristol},
  issn      = {0953-8984},
  doi       = {10.1088/0953-8984/24/39/394009},
  pages     = {11},
  year      = {2012},
  abstract  = {The scanning tunnelling microscope (STM)-induced switching of a single cyclooctadiene molecule between two stable conformations chemisorbed on a Si(100) surface is investigated using an above threshold model including a neutral ground state and an ionic excited state potential. Switching was recently achieved experimentally with an STM operated at cryogenic temperatures (Nacci et al 2008 Phys. Rev. B 77 121405(R)) and rationalized by a below threshold model using just a single potential energy surface (Nacci et al 2009 Nano Lett. 9 2997). In the present paper, we show that experimental key findings on the inelastic electron tunnelling (IET) switching can also be rationalized using an above threshold density matrix model, which includes, in addition to the neutral ground state potential, an anionic or cationic excited potential. We use one and two-dimensional potential energy surfaces. Furthermore, the influence of two key parameters of the density matrix description, namely the electronic lifetime of the ionic resonance and the vibrational lifetimes, on the ground state potential are discussed.},
  language  = {en}
}