Low-energy configurations of PtCu clusters and their physical-chemical characterization: a high-accuracy DFT study.

Based on a combination of many-body potentials, an analysis of the inertia tensors and a Density Functional Theory framework, we use a method to harvest the lowest energy states of any set of cluster systems. Then, this methodology is applied to the PtCu cluster case and the structural, chemical, electronic, anisotropy, magnetic and vibrational properties of the lowest energy isomers are studied. Unexpectedly, some tens of isomers with much lower energy than the precedent believed ground state [, (4):044701] are found, which indicates the goodness of this methodology.

Encapsulation effect of π-conjugated quaterthiophene on the radial breathing and tangential modes of semiconducting and metallic single-walled carbon nanotubes.

We developed a hybrid approach, combining the density functional theory, molecular mechanics, bond polarizability model and the spectral moment's method to compute the nonresonant Raman spectra of a single quaterthiophene (4T) molecule encapsulated into a single-walled carbon nanotube (metallic or semiconducting). We reported the optimal tube diameter allowing the 4T encapsulation. The influence of the encapsulation on the Raman modes of the 4T molecule and those of the nanotube (radial breathing modes and tangential modes) are analyzed.

(Cu)(CrSn)SSe Spinels: Crystal Structure, Density Functional Theory Calculations, and Magnetic Behavior.

A new series of (Cu)[CrSn]SSe compounds was prepared by solid-state reaction at high temperature. Determination of the crystal structures by single-crystal X-ray diffraction revealed that CuCrSnSSe, CuCrSnSSe, CuCrSnSSe, and CuCrSnSSe crystallize in a normal spinel-type structure (cubic 3 space group). The powder X-ray diffraction patterns and Rietveld refinements of nominal CuCrSnSSe ( = 0.

A charge optimized many-body potential for iron/iron-fluoride systems.

A classical interatomic potential for iron/iron-fluoride systems is developed in the framework of the charge optimized many-body (COMB) potential. This interatomic potential takes into consideration the effects of charge transfer and many-body interactions depending on the chemical environment. The potential is fitted to a training set composed of both experimental and ab initio results of the cohesive energies of several Fe and FeF2 crystal phases, the two fluorine molecules F2 and the F2-1 dissociation energy curve, the Fe and FeF2 lattice parameters of the ground state crystalline phase, and the elastic constants of the body centered cubic Fe structure.