Matsokin D. Spectral densities of resonant states in crystals with plane defects

The thesis is devoted to investigation of bulk vibration changes caused by presence of plane defects and it is devoted to connection between peculiarities of states densities and effects of total transition and total reflection. It is shown the effects of total transition and total reflection of quasiparticles from thin passive defect can occur in systems where the dispersion law of elementary perturbation has several branches. In this case density of quasilocalized states has a peak described by a Lorenz function. The peak maximum is close to frequency of total transotion. The dispersion curves corresponding to total transition effect are continued outside the bulk spectrum by dispersion curves of localized waves.