 This work investigates the scattering behavior of a ballistic phonon wave incident on a dopant spherical nanoparticle embedded within a pure crystal through molecular dynamic simulations, and also conducts conjugate simulations of ballistic phonon scattering on a dopant thin slab to compare and contrast scattering by non-planar heterogeneous interfaces, nanoparticle, and planar heterogeneous interfaces, thin slab. The analysis reveals that the specific states of mode conversion in the nanoparticle scattering system are due to an unreported phonon lensing effect where the phonon wave propagation is altered by refraction and reflection through the non-planar interfaces of the nanoparticle. The lensing phenomenon is absent in the phonon scattering by the thin slab, resulting in differences in the scattering behaviors between the planar and non-planar interfaces. This article was authored by Theodore Marinette and Yang Wang.