Wave packet dynamics for atomic projectile in solid film

The physics of phenomena extended during the passage of a swift atomic projectile through solid has a long history. A considerable amount of works was performed and a wide class of the so-called orientation phenomena was revealed. The theory of such phenomena usually based on assumption on a strength spatial localization of massive accelerated particles (nucleons, nuclei) having a sufficiently great velocity in a solid. The other point of view was proposed by Kagan {\&} Kononetz, when it was stated a particle moving in a crystal should be described with the help of one Bloch wave and obviously should be delocalized. It was shown the channeling phenomena could be well described also with this theory. The width of a particle's wave packet is important in some physical effects, e.g., in diffraction. With the help of density matrix calculation we show a presence of a spatial localization for a projectile. We estimate the time behavior of a packet width and show the specific effects of memory and stabilization, which follow from a wave nature of a micro-world. We show also the sophistic nature of a free wave packet notion which can not be realized in reality.