Reflection-free propagation of wave packets

We analyze the problem of suppression of reflections within the numerical p ropagation of wave packets using finite atomiclike pseudostate expansions. Artificial reflections at effective "walls" and reentering of probability f lux into the interaction region represents a major limitation for the study of long-time evolution of atomic ionization processes. We propose two meth ods, the repetitive projection method (RPM) and Siegert pseudostate (SPS) p ropagation, and study their efficiency in Suppressing reflections. It is sh own that the quantum Zeno effect sets a limit on the efficiency of the RPM as well as of masking functions. For the exactly solvable propagation of a radial-free wave packet, we show that both the SPS and the RPM provide almo st complete suppression of reflections without appreciable distortion in th e physically relevant region of coordinate space. [S1050-2947(99)03908-6].