SPONTANEOUS PHOTON-EMISSION IN ISOLATED-CORE EXCITED RYDBERG SYSTEMS AND DYNAMICS OF ELECTRONIC WAVE-PACKETS

In isolated-core excited Rydberg systems the destruction of quantum co herence by spontaneous emission of photons is investigated. For this p urpose a theoretical description is developed which is based on a deco mposition of the atomic density operator into N-photon contributions. Using methods from multichannel quantum defect theory, the relevant at omic transition amplitudes are represented in the form of semiclassica l path representations which are associated with repeated returns of t he Rydberg electron to the ionic core. Apart from numerical advantages , this approach also yields a clear physical picture of the intricate interplay between the incoherent photon emission process, the coherent laser-modified electron correlation effects, and the semiclassical as pects of the dynamics of the Rydberg electron. Various examples of thi s interplay are analyzed within the framework of the developed theoret ical tools.