Latest documents http://publikationen.ub.uni-frankfurt.de/index/index/ Tue, 07 Nov 2006 10:17:27 +0200 Tue, 07 Nov 2006 10:17:27 +0200 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2423 Ionization, pair creation, and electron excitations in relativistic heavy-ion collisions are investigated in the framework of the coupled-channel formalism. Collisions between heavy projectiles and Pb82+ are considered for various bombarding energies in the region E=500 up to 2000 MeV/u. Useful symmetry relations for the matrix elements are derived and the influence of gauge transformations onto the coupled-channel equations is explored. Klaus Rumrich; Gerhard Soff; Walter Greiner article http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2423 Tue, 11 Jul 2006 10:17:27 +0200 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2669 Using relativistic Green’s-function techniques we examined single-electron excitations from the occupied Dirac sea in the presence of strong external fields. The energies of these excited states are determined taking into account the electron-electron interaction. We also evaluate relativistic transition strengths incorporating retardation, which represents a direct measure of correlation effects. The shifts in excitation energies are computed to be lower than 0.5%, while the correlated transition strengths never deviate by more than 10% from their bare values. A major conclusion is that we found no evidence for collectivity in the electron-positron field around heavy and superheavy nuclei. D. C. Ionescu; Walter Greiner; Berndt Müller; Gerhard Soff article http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/2669 Tue, 11 Jul 2006 10:10:05 +0200