Ultrafast collective electron dynamics in open-shell ions

We use the time-dependent R-matrix approach to investigate an ultra-short pump-probe scheme to observe collective electron dynamics in C+. The ionization probability of a coherent superposition of the 2s2p2 2D and 2S states shows rapid oscillations due to collective dynamics of the two equivalent 2p electrons, with the frequency of the oscillations linked to the electron-electron interaction. We find that deeper insight into this collective dynamics is gained by transforming the atomic structure from LS symmetry to the uncoupled basis. We discuss how such dynamics may be important in high-harmonic generation using open-shell atoms and ions.