Abstract
A new approach treats spin-orbit and electric-dipole interactions simultaneously and proves that the notion of quantum "interference" is a misinterpretation based on inappropriate assumptions. Instead, fine-structure (fs-) quantum beats result from the conservation of the spin in spontaneous E1 transitions between in-phase precession states with different nutation frequencies as imposed by the spin-orbit interaction. The theory also adds new aspects regarding the origin of sensitized fluorescence by showing that mixed states and not fs-eigenstates are the most probable ones. Moreover, it predicts orientationally dependent lifetimes in spin-orbit interacting sublevels, dynamically reduced transition probabilities, and Fano-type lineshapes.