Dynamics of Disordered Harmonic Lattices. I. Normal-Mode Frequency Spectra for Randomly Disordered Isotopic Binary Lattices

Abstract

Results of computer calculations of normal-mode frequency spectra of certain binary isotopically disordered harmonic lattices are presented. Linear chains, and square, triangular, simple-cubic, and body-centered cubic lattices are discussed. Interesting features of the results include dramatic changes in the nature of the spectra as the mass ratio of the two components or their relative concentration is varied. Discussions are given of the physical interpretation of the special frequencies of the linear chain and of a possible extension to higher dimensions.