10.18453/rosdok_id00002338 Wang, Huihui Huihui Wang http://d-nb.info/gnd/1172227802 Universität Rostock 2018 530 Physics 2018 en http://purl.uni-rostock.de/rosdok/id00002338 urn:nbn:de:gbv:28-diss2018-0166-0 Recent advances in attosecond spectroscopy open the door to the understanding correlated motion of valence and core electrons in molecular systems. In this thesis, the density matrix-based TD-RASCI method is used to study the electron and spin-flip dynamics. The dephasing effect of nuclear vibrations is incorporated implicitly making use of an electronic system/vibrational bath partitioning. We theoretically addressed the ultrafast spin-flip dynamics in a transition metal complex which is triggered by isolated sub-fs soft-X-ray pulses as well as X-ray pulse trains.