Physical Review B vol:6313 issue:13 pages:2203,NIL-2203,NIL
The direct, proportionality relation between the boson peak maximum in glasses omega (b) and the Ioffe-Regel crossover frequency for phonons omega (d) is established. For several investigated materials omega (b) = (1.5 +/- 0.1)omega (d). At frequency omega (d) the mean free path of the phonons l becomes equal to their wavelength because of strong resonant scattering on quasilocal harmonic oscillators. We prove that the established correlation between omega (b) and omega (d) holds in the general case and is a direct consequence of bilinear coupling of quasilocal oscillators with the strain field.