Localization and kinetics of an atom in the spectral filtration of its resonance fluorescence

It is shown that spectral filtration of a significant fraction of radiation of a resonantly fluorescing atom changes its kinetics. The effect of a spectral observation event on the behavior of an atom is demonstrated by two examples: localization of an atom at its flight through a region occupied by a standing light wave and translatory dynamics of an atom at its motion along a standing light wave. In the first case, localization probabilities are calculated in the absence of spontaneous emission events and for one photoemission event. The arising distribution over the atomic momentum, which is sensitive to spectral filtration, is also calculated for one photoemission event. In the second example, it is shown that spectral filtration of spontaneous emission leads to the occurrence of an anomalous additive to the force acting on an atom in the standing-wave field.