MOLECULAR-DYNAMICS STUDY OF LATTICE-VIBRATIONS IN THE MIXED-CRYSTAL K0.5RB0.5CL

We have performed molecular-dynamics simulations on a system of 512 ions arranged on a sodium chloride lattice, consisting of 256 chlorine ions, and a random mixture of 128 potassium ions and 128 rubidium ions, interacting through Coulombic and short-range rigid-ion potentials. Results are presented for the scattering function S(Q,omega) for a range of wave vectors, and for the Fourier-transformed velocity-velocity autocorrelation function. Peaks in the scattering function for the mixture are broader than those of pure KCl and are in some cases split.