The exchange charge model of crystal field theory has been used to analyze the ground and excited state absorption of tetrahedrally coordinated Cr ion in lithium aluminum oxide LiAlO2 (γ-phase) and lithium dioxogallate LiGaO2. The parameters of the crystal field acting on the Cr ion are calculated from the crystal structure data, taking into account the crystal lattice ions located at distances...

The influence of a time-dependent oscillatory external field on the melting transition of a polydisperse colloidal crystal is examined by theory and computer simulation. In a monodisperse crystal the field just induces an overall dynamical mode which does not affect the melting line. For a polydisperse sample, on the other hand, the field shifts the melting line towards smaller temperatures. Co...

Density functional theory provides an ideal microscopic theory to address freezing and crystallization problems. We review the application of static density functional theory for the calculation of equilibrium phase diagrams. We also describe the dynamical extension of density functional theory for systems governed by overdamped Brownian dynamics. Applications of density functional theory to cr...

A two-dimensional crystal of repulsive dipolar particles is studied in the vicinity of its melting transition by using Brownian dynamics computer simulation, dynamical density-functional theory, and phase-field-crystal modeling. A vacancy is created by taking out a particle from an equilibrated crystal, and the relaxation dynamics of the vacancy is followed by monitoring the time-dependent one-...

We derive a set of rotationally covariant amplitude equations for use in multiscale simulation of the two-dimensional phase-field crystal model by a variety of renormalization-group (RG) methods. We show that the presence of a conservation law introduces an ambiguity in operator ordering in the RG procedure, which we show how to resolve. We compare our analysis with standard multiple-scale tech...