Inelastic neutron scattering from amorphous solids. I. Calculation of the scattering law for model structures

Abstract

We present a method for calculating the one- and two-phonon law $S(Q,\ensuremath{\omega})$ for models of amorphous solids. The calculation is considerably simplified by explicitly performing the necessary orientation averages. We illustrate use of the method by calculating the one-phonon scattering from long-wavelength acoustic waves in an amorphous solid. In the small-$Q$ region a Brillouin scattering is predicted.