An improved error bound for a finite element approximation of a model for phase separation of a multi-component alloy

Using the approach of Rulla (1996 SIAM J. Numer. Anal. 33, 68-87)for analysing the time discretization error and assuming moreregularity on the initial data, we improve on the error boundderived by Barrett and Blowey (1996 IMA J. Numer. Anal. 16,257-287) for a fully practical piecewise linear finite elementapproximation with a backward Euler time discretization of amodel for phase separation of a multi-component alloy.     

Finite element approximation of a model for phase separation of a multi-component alloy with a concentration-dependent mobility matrix

We consider a model for phase separation of a multi-componentalloy with a concentration-dependent mobility matrix and logarithmicfree energy. In particular we prove that there exists a uniquesolution for sufficiently smooth initial data. Further, we provean error bound for a fully practical piecewise linear finiteelement approximation in one and two space dimensions. Finallynumerical experiments with three components in one space dimensionare presented.     

Electrostatic lattice energies of some ABX3 polytypes with close-packed AX3 layers

Electrostatic lattice energies (Madelung and polarization energies) for five ideal ABX₃, structure types with close-packed AX₃ layers (X = F, Cl, Br, I, O, S) are calculated. Stability regions for the ideal structure types are indicated as function of the anion radius and the anion polarizability. The effect on the electrostatic lattice energy due to trigonal deformations of the AX₃ layers in the 2L and 3L stacked structures is discussed for the anions F and Cl.