Role of the trigonal warping on the minimal conductivity of bilayer graphene

Using a reformulated Kubo formula we calculate the zero-energy minimal conductivity of bilayer graphene taking into account the small but finite trigonal warping. We find that the conductivity is independent of the strength of the trigonal warping and it is three times as large as that without trigonal warping, and six times larger than that in single layer graphene. Although the trigonal warping of the dispersion relation around the valleys in the Brillouin zone is effective only for low energy excitations, our result shows that its role cannot be neglected in the zero-energy minimal conductivity.Comment: 4 pages, 1 figur

Validation of the CoGEF Method as a Predictive Tool for Polymer Mechanochemistry

The development of force-responsive molecules called mechanophores is a central component of the field of polymer mechanochemistry. Mechanophores enable the design and fabrication of polymers for a variety of applications ranging from sensing to molecular release and self-healing materials. Nevertheless, an insufficient understanding of structure–activity relationships limits experimental development, and thus computation is necessary to guide the structural design of mechanophores. The constrained geometries simulate external force (CoGEF) method is a highly accessible and straightforward computational technique that simulates the effect of mechanical force on a molecule and enables the prediction of mechanochemical reactivity. Here, we use the CoGEF method to systematically evaluate every covalent mechanophore reported to date and compare the predicted mechanochemical reactivity to experimental results. Molecules that are mechanochemically inactive are also studied as negative controls. In general, mechanochemical reactions predicted with the CoGEF method at the common B3LYP/6-31G* level of density functional theory are in excellent agreement with reactivity determined experimentally. Moreover, bond rupture forces obtained from CoGEF calculations are compared to experimentally measured forces and demonstrated to be reliable indicators of mechanochemical activity. This investigation validates the CoGEF method as a powerful tool for predicting mechanochemical reactivity, enabling its widespread adoption to support the developing field of polymer mechanochemistry. Secondarily, this study provides a contemporary catalog of over 100 mechanophores developed to date

Validation of the CoGEF Method as a Predictive Tool for Polymer Mechanochemistry

The development of force-responsive molecules called mechanophores is a central component of the field of polymer mechanochemistry. Mechanophores enable the design and fabrication of polymers for a variety of applications ranging from sensing to molecular release and self-healing materials. Nevertheless, an insufficient understanding of structure–activity relationships limits experimental development, and thus computation is necessary to guide the structural design of mechanophores. The constrained geometries simulate external force (CoGEF) method is a highly accessible and straightforward computational technique that simulates the effect of mechanical force on a molecule and enables the prediction of mechanochemical reactivity. Here, we use the CoGEF method to systematically evaluate every covalent mechanophore reported to date and compare the predicted mechanochemical reactivity to experimental results. Molecules that are mechanochemically inactive are also studied as negative controls. In general, mechanochemical reactions predicted with the CoGEF method at the common B3LYP/6-31G* level of density functional theory are in excellent agreement with reactivity determined experimentally. Moreover, bond rupture forces obtained from CoGEF calculations are compared to experimentally measured forces and demonstrated to be reliable indicators of mechanochemical activity. This investigation validates the CoGEF method as a powerful tool for predicting mechanochemical reactivity, enabling its widespread adoption to support the developing field of polymer mechanochemistry. Secondarily, this study provides a contemporary catalog of over 100 mechanophores developed to date

The migration and attrition behaviour among Hungarian radiographers

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Thermoelectric Performance of various Benzo-difuran Wires

Using a first principles approach to electron transport, we calculate the electrical and thermoelectrical transport properties of a series of molecular wires containing benzo-difuran subunits. We demonstrate that the side groups introduce Fano resonances, the energy of which is changing with the electronegativity of selected atoms in it. We also study the relative effect of single, double or triple bonds along the molecular backbone and find that single bonds yield the highest thermopower, approximately 22$\mu$V/K at room temperature, which is comparable with the highest measured values for single-molecule thermopower reported to date.Comment: 7 pages, 8 figure