Computer Experiments on Propagation and Elastic Scattering of Beams of Down-converting Phonons

We present the program MCAnScat which simulates propagation of beams of down-converting phonons in anisotropic cubic and isotropic media containing point mass defects. It is assumed that the excitation the phonon subsystem is low-level. The program produces time-of-flight spectrograms and phonon energy and quasi-momentum focusing patterns for samples having the form of a rectangular parallelepiped, as well as for cylindric and spherical specimens. Wave vectors of beam phonons belong to body angles ranging from 4B to zero. The axes of corresponding cones are arbitrarily oriented. When down-conversion processes are excluded the outcomes of experiments on initial spatially homogeneous states and on diffusive propagation of phonons are compared with exact results obtained for isotropic and cubic media. As an example of application of MCAnScat we study ballistic and diffusive propagation of beams of phonons in GaAs. The obtained results are in excellent agreement with theoretical and experimental findings. PACS numbers: 05.10.Ln. 63.20.-e, 66.70.+f