Molecular origin of the two-step mechanism of gellan aggregation.

Among hydrocolloids, gellan is one of the most studied polysaccharides due to its ability to form mechanically stable gels. Despite its long-standing use, the gellan aggregation mechanism is still not understood because of the lack of atomistic information. Here, we fill this gap by developing a new gellan force field.

Nanoscale morphology and electronic coupling at the interface between indium tin oxide and organic molecular materials.

The correlation between nanoscale morphology and charge injection rates at the interface between an organic semiconductor layer and a transparent metal oxide electrode was investigated by integrating molecular dynamics simulations with electronic structure calculations. The simulation approach proposed has been applied to the analysis of the hole injection mechanism at the interface between an amorphous layer of tris[(3-phenyl-1H-benzimidazol-1-yl-2(3H)-ylidene)-1,2-phenylene]Ir (DPBIC), a hole transport and emitter molecule, and the surface of indium tin oxide (ITO), a material commonly used as anode in OLEDs. The link between interface morphology and charge injection was investigated by implementing a two-step, top-down simulation approach.

Validity of Weyl fermion picture for transition metals monopnictides TaAs, TaP, NbAs, and NbP from ab initio studies.

We investigate electronic and optical properties of the topological Weyl semimetals TaAs, TaP, NbAs and NbP crystallizing in bct geometry by means of the ab initio density functional theory with spin-orbit interaction within the independent-particle approximation. The small energetical overlap of Ta5d or Nb4d derived conduction and valence bands leads to electron and/or hole pockets near the Fermi energy at the 24 Weyl nodes. The nodes give rise to two-(three-)dimensional Dirac cones for the W (W) Weyl type.

Electronic and optical properties of topological semimetal CdAs.

Using ab initio density functional theory the band structure and the dielectric function of a bct CdAs crystal are calculated. We find a Dirac semimetal with two Dirac nodes k near the Γ point on the tetragonal axis. The bands near the Fermi level exhibit a linear behavior.

Many-Body Perturbation Theory Extended to the Quantum Mechanics/Molecular Mechanics Approach: Application to Indole in Water Solution.

Optical properties of aromatic chromophores are used to probe complex biological processes, yet how the environment tunes their optical properties is far from being fully understood. Here we present a method to calculate such properties on large-scale systems, like biologically relevant molecules in aqueous solution. Our approach is based on many-body perturbation theory combined with a quantum mechanics/molecular mechanics (QM/MM) approach.

Electronic structure of surface-supported bis(phthalocyaninato) terbium(III) single molecular magnets.

The electronic structure of isolated bis(phthalocyaninato) terbium(III) molecules, a novel single-molecular-magnet (SMM), supported on the Cu(111) surface has been characterized by density functional theory and scanning tunneling spectroscopy. These studies reveal that the interaction with the metal surface preserves both the molecular structure and the large spin magnetic moment of the metal center. The 4f electron states are not perturbed by the adsorption while a strong molecular/metal interaction can induce the suppression of the minor spin contribution delocalized over the molecular ligands.