A possible spectrum of positron states in porous silicon

A kinetic scheme of transformations and annihilation decays of positron and positronium states is considered in the bulk of a crystal in the crystal skeleton, and on the surface and in the bulk of pores of porous silicon. Formulas relating the intensities of temporal components of annihilation decay to the rates of decays and transformations of positron and positronium states in the pore volume are derived. The rate of interaction with the pore surface, accompanied by the formation of the surface state of a positronium atom, is estimated at 10⁷–10⁸ s^?1, while the estimated value for the pore radius is ≈2 nm.