Dynamics of the rutile structure. II. Lattice dynamics of magnesium fluoride

Abstract

See also abstr. A11887 of 1970. The lattice dynamics of magnesium fluoride has been studied using a rigid ion model with short-range central axially symmetric forces and long-range Coulomb forces. In order to get the symmetry required by the elastic constants of the crystal it was found necessary to minimize the potential function against every structural parameter of the crystal. The elastic constants and the dispersion relations for the phonons propagating along ( zeta 00), (00 zeta ) and ( zeta zeta 0) are computed and compared with the experimental values. The wave vector dependence of the dipolar modes is discussed.