A mixed radial, angular, three-body distribution function as a tool for local structure characterization: Application to single-component structures.

A mixed radial, angular three-body distribution function g(r, θ) is introduced, which allows the local atomic order to be more easily characterized in a single graph than with conventional correlation functions. It can be defined to be proportional to the probability of finding an atom C at a distance r from atom B while making an angle θ with atoms A and B, under the condition that atom A is the nearest neighbor of B. As such, our correlation function contains, for example, the likelihood of angles formed between the nearest and the next-nearest-neighbor bonds.

Determination of accurate, mean bond lengths from radial distribution functions.

The mean bond length d between a central atom and its nearest neighbors can be estimated from the position of the first peak in the radial distribution function g(r). However, as we demonstrate here, this estimate does not allow one to deduce temperature-induced changes in d. Instead, skewness has to be included into the analysis, which can be achieved, for example, via the skew normal distribution (SND).

Constraints on phase stability, defect energies, and elastic constants of metals described by EAM-type potentials.

We demonstrate that the embedded-atom method and related potentials predict many dimensionless properties of simple metals to depend predominantly on a single coefficient μ, which typically lies between 0.3 and 0.45.

Charge-transfer potentials for ionic crystals: Cauchy violation, LO-TO splitting, and the necessity of an ionic reference state.

In this work, we study how including charge transfer into force fields affects the predicted elastic and vibrational Γ-point properties of ionic crystals, in particular those of rock salt. In both analytical and numerical calculations, we find that charge transfer generally leads to a negative contribution to the Cauchy pressure, P(C) ≡ C12 - C66, where C12 and C66 are elements of the elastic tensor. This contribution increases in magnitude with pressure for different charge-transfer approaches in agreement with results obtained with density functional theory (DFT).

Structure-dependent interatomic dispersion coefficients in oxides with maximally localized Wannier functions.

The interatomic C(6) dispersion coefficients in crystalline and amorphous SiO(2) and ZrO(2) structures were obtained with the approach proposed by Silvestrelli (2008 Phys. Rev. Lett.