Using first principles density functional theory (DFT), the electronic and magnetic properties as well as the Li-ion migration in LiCoO2 have been studied with a gradient corrected functional. The magnetic properties were also investigated in addition using a gradient corrected functional in combination with an on-site repulsion U and a hybrid functional. We find LiCoO2 to be non-magnetic under ambient conditions. A magnetic ground state can be obtained by a volume expansion corresponding to a negative pressure of -8 GPa due to a competition between Hund's rules favoring magnetism on the Co(3+) ions and the crystal field splitting, which suppresses magnetism at zero pressure. The barrier for lithium transport is determined to be 0.44 eV from nudged elastic band (NEB) calculations on the Li0.917CoO2 system.

We have performed a density functional calculation for the centrosymmetric neodymium gallate using a full-potential linear augmented plane wave method with the LDA and LDA+U exchange correlation. In particular, we explored the influence of U on the band dispersion and optical transitions. Our calculations show that U = 0.55 Ry gives the best agreement with our ellipsometry data taken in the VUV spectral range with a synchrotron source. Our LDA+U (U = 0.55) calculation shows that the valence band maximum (VBM) is located at T and the conduction band minimum (CBM) is located at the center of the Brillouin zone, resulting in a wide indirect energy band gap of about 3.8 eV in excellent agreement with our experiment. The partial density of states show that the upper valence band originates predominantly from Nd-f and O-p states, with a small admixture of Nd-s/p and Ga-p B-p states, while the lower conduction band prevailingly originates from the Nd-f and Nd-d terms with a small contribution of O-p-Ga-s/p states. The Nd-f states in the upper valence band and lower conduction band have a significant influence on the energy band gap dispersion which is illustrated by our calculations. The calculated frequency dependent optical properties show a small positive uniaxial anisotropy.

An ab initio density functional theory-based study of the electronic band structure, the elastic, electric, elastoelectric, and linear and nonlinear optical properties of the new ion conductor LiB 6 O 9 F, has been performed. The computed band structure reveals a wide direct band gap. The coefficients of the second order nonlinear susceptibility χ (2) were found to be comparable to those of KH 2 PO 4 . Corresponding experimental investigations of second harmonic generation comply with the respective ab initio calculations.

Saccharides are ubiquitous biomolecules, but little is known about their interaction with, and assembly at, surfaces. By combining preparative mass spectrometry with scanning tunneling microscopy, we have been able to address the conformation and self‐assembly of the disaccharide sucrose on a Cu(100) surface with subunit‐level imaging. By employing a multistage modeling approach in combination with the experimental data, we can rationalize the conformation on the surface as well as the interactions between the sucrose molecules, thereby yielding models of the observed self‐assembled patterns on the surface.

Süße Oberfläche Durch Elektrospray‐Ionenstrahlabscheidung kann nichtflüchtige Sucrose auf sauberen Oberflächen abgelagert werden. S. Abb et al. präsentieren in ihrer Zuschrift auf S. 8424 ff. eine kristalline 2D‐Anordnung von Sucrose auf einer Cu(100)‐Oberfläche. Mit einer Kombination aus Rastertunnelmikroskopie und mehrstufiger Modellierung werden die Konformation und das Assemblierungsmuster der Sucrose sichtbar.

No abstract

We rationalize the experimentally observed variety of trehalose assemblies on Cu(100) by modeling based on STM images and global optimization.

No abstract