Abstract
The quasiclassical theory of the Landau-Zener resonance arising because of the atomic motion in the field of a strong standing light wave is developed. A resonance atom in a spatially inhomogeneous field as two effective potentials and two trajectories of motion. The Landau-Zener (LZ) transitions from one trajectory to the other take place in the regions of quasi-intersection of the terms (standing-wave nodes). This effect leads to the appearance of strong quantum fluctuations which break the potential character of the atomic motion and result in the interference of the translational motion states. Therefore a number of the features of the atomic dispersion in the standing-wave field arise (anomalous widths of the forbidden gaps and allowed bands in the under-barrier energetic region and oscillations of the density of states in the over-barrier energetic region). The manifestation of LZ resonance in non-linear spectroscopy and for bipotential scattering of atoms by light is considered.