Role of magnitude sublevels in anomalous standing-wave diffraction of atoms

The influence of the initial state preparation by an interaction with resonant traveling waves on the anomalous standing wave scattering of a two-level system with magnetic sublevels for arbitrary coherency (1) between the atomic sublevels and (2) between the polarizations of counterpropagating waves is discussed. The potential of the magnetic sublevels and light polarization in the formation of specific types of split initial momentum distributions is pointed out. It is found a new effect of narrowing of the interference fringes of the diffraction pattern taking place at particular case of the initial wave packet splitting involving two translation states, whose momenta differ by two photon momenta, corresponding to the same energy level. It is shown that this narrowing can be combined with the known asymmetric scattering.