Inhomogeneity of the spatial distribution of vibrational modes in a computer model of amorphous argon

Abstract

The dynamic behavior of atoms in the more regular and more disordered regions in a molecular dynamics model of glassy argon is investigated. Partial velocity autocorrelation functions and their Fourier transforms are calculated for both types of regions. It is found that the more disordered regions are responsible for an excess density of low-frequency motions. The relation of this low-frequency excess to the so-called boson peak in the vibrational spectra of glasses is discussed.